CONTENTS

1. GENERAL PROVISIONS. 5

1.1. Scope. 5

1.2. Subjects of application. 5

1.3. References. 5

1.4. Definitions. 6

1.5. Symbols 8

1.6. Abbreviations 9

2. TECHNICAL SPECIFICATIONS. 10

2.1. Environmental conditions 10

2.2. General provisions 10

2.3. Requirements for the transmitter 11

2.3.1. Operating frequency range. 11

2.3.2. Mean power 11

2.3.3. Peak power 12

2.3.4. Unwanted emissions in the out-of-band domain. 12

2.3.5. Unwanted emissions in the pseudo-domain. 14

2.4. Requirements for the receiver 14

2.4.1. Receiver spurious emissions 14

2.4.2. Receiver in-band, out-of-band and remote control signals. 15

3. MEASUREMENT METHODS. 16

3.1. Test for transmitter 16

3.1.1. Operating frequency range. 16

3.1.2. Mean power 16

3.1.3. Peak power 17

3.1.4. Unwanted emissions in the out-of-band domain. 18

3.1.5. Unwanted emissions in the pseudo-domain. 20

3.2. Test for the receiver 20

3.2.1. Receiver spurious emissions 20

3.2.2. Receiver in-band, out-of-band, and remote control signals. 21

4. MANAGEMENT PROVISIONS. 22

5. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS. 22

6. IMPLEMENTATION ORGANIZATION.. 22

Appendix A  (Normative)  General conditions 23

Appendix B  (Normative)  Measurement setup and measurement procedure. 30

Appendix C  (Normative)  Test areas and general arrangements for measurements involving the use of radiated fields. 34

Appendix D  (Normative)  Standard test method. 42

Appendix E  (Normative)  Rx path calculation. 44

Appendix F  (Normative)  Measuring receiver 48

Appendix G  (Normative)  HS code of radar equipment operating in the frequency range 76 GHz to 77 GHz for ground based vehicle. 51

Bibliography of references. 52

Introduction

QCVN 124:2021/BTTTT was compiled by the Department of Telecommunications, submitted by the Department of Science and Technology, reviewed by the Ministry of Science and Technology, and issued by the Minister of Information and Communications together with the Circular No. 09/2021/TT-BTTTT dated October 20, 2021.

NATIONAL TECHNICAL REGULATION ON RADAR EQUIPMENT OPERATING IN THE FREQUENCY RANGE 76 GHZ TO 77 GHZ FOR GROUND BASED VEHICLE
 

1. GENERAL PROVISIONS

1.1. Scope

This Regulation details the specifications and test methods for radar equipment using an integrated antenna operating in the frequency range 76 GHz to 77 GHz for ground based vehicle. This Regulation applies to transmitters and integrated transceivers.

This Regulation also specifies requirements for short-range radio equipment for groundbased vehicle, e.g. active cruise control system, collision warning system, blind spot detection system, parking assist, backup assist and other future applications.

This Regulation does not cover all the features that may be required by the user, nor does it fully represent the optimum performance that the equipment can achieve.

In the event of a discrepancy (e.g. concerning special conditions, definitions, abbreviations) between this regulation and another, the provisions of this regulation shall prevail.

These types of radar equipment are capable of operating in all or part of the frequency range given in Table 1.

Table 1 - Operating frequency range of the device

The HS code of radar equipment operating in the frequency range 76 GHz to 77 GHz for ground based vehiclecomplies with Appendix G.

1.2. Subjects of application

This Regulation applies to Vietnamese and foreign agencies, organizations and individuals engaged in the production and business of devices covered by this Regulation in the Vietnamese territory.

1.3. References

CEPT/ERC Recommendation 70-03: "Relating to the use of Short Range Devices (SRD)"

EC Decision 2013/752/EU: "Commission implementing Decision of 11 December 2013 amending Decision 2006/771/EC on harmonisation of the radio spectrum for use by short-range devices and repealing Decision 2005/928/EC".

CEPT/ERC/REC 74-01: "Unwanted emissions in the spurious domain".

CISPR 16-1-1 (2006), CISPR 16-1-4 (2010) and CISPR 16-1-5 (2014): "Specification for radio disturbance and immunity measuring apparatus and methods; Part 1: Radio disturbance and immunity measuring apparatus".

ETSI TR 100 028 (V1.4.1) (all parts): "Electromagnetic compatibility and Radio Spectrum Matters (ERM); Uncertainties in the measurement of mobile radio equipment characteristics".

ETSI TR 102 273 (V1.2.1) (all parts): "Electromagnetic compatibility and Radio Spectrum Matters (ERM); Improvement on Radiated Methods of Measurement (using test site) and evaluation of the corresponding measurement uncertainties".

Recommendation ITU-R SM.329-12 (2012): "Unwanted emissions in the spurious domain".

Recommendation ITU-R SM.328-11 (2006): "Spectra and Bandwidth of Emissions".

1.4. Definitions

1.4.1. Antenna cycle

Antenna cycle is one complete scan of the beam in a given space of a mechanical or electrical scanning antenna.

1.4.2. Antenna scan duty factor

Antenna scan duty factor is the ratio of the fixed angle of the antenna beam (measured at the 3 dB point) to the total fixed angle scanned by the antenna.

1.4.3. Averaging time

Averaging time is the preset interval for the average measurement.

1.4.4. Boresight

Boresightis the direction in which the maximum gain of a directional antenna is achieved.

NOTE: The EUT may have different axial orientations for the transmitting and receiving antennas.

1.4.5. Co-located receiver

Co-located receiver is a receiver that is housed in the same equipment box as the transmitter.

1.4.6. Cycle time

Cycle time is the length of time between the system's periodic transmission patterns.

NOTE: In the case of a random pattern, the default value is 1 min.

1.4.7. Duty cycle

Duty cycle is calculated by the following formula: Σ(T_on)/t_o. Where: T_on is the ON time of one transmission and t_o is the observation time. T_on is measured in one observation bandwidth (BW_o).

1.4.8. Equipment Under Test (EUT)

Equipment under test is a multi-sensor radar equipment which consists of an integrated antenna together with any external antenna elements that affect its performance.

1.4.9. Equivalent isotropically radiated power (e.i.r.p.)

Equivalent isotropically radiated power is the component of the power delivered to the antenna and the gain of the antenna in a given direction relative to an isotropic (independent or isotropic) antenna.

NOTE: e.i.r.p. may be used for peak or mean power and peak power or mean power spectral densities. Unless otherwise noted, e.i.r.p. refers to the mean power.

1.4.10. Far field measurement

Farfield measurement is a measurement at a distance from the antenna sufficient to ensure that the electric magnetic field approximates that of a plane wave.

1.4.11. Illumination time

Illumination time (for equipment with a scanning antenna) is the time that a given point in the far field is within the main beam range of the antenna.

1.4.12. Maximum power

Maximum power is the maximum average power relative to the azimuth and elevation angle (usually measured in the axial direction of the antenna).

1.4.13. Mean power

Mean power is the power over a sufficiently long period of time relative to the lowest frequency within the modulation envelope.

NOTE: For pulse systems, mean power is equal to the peak envelope power (see ITU Radio Regulations [i.2], RR 1.157) multiplied by the load factor. For a CW system without a break time, mean power is equal to the transmitted power without modulation.

1.4.14. Operating frequency (operating centre frequency)

Operating frequency is the nominal operating frequency of the device.

NOTE:Device can operate at one or more different frequencies.

1.4.15. Operating frequency range

Operating frequency range is the range over which the device can be tuned through switching or reprogramming or oscillator tuning.

NOTE 1: For pulsed or phase-shifted systems without an additional tuning carrier, the operating frequency range is fixed on a single transmission line.

NOTE 2:For discrete or analog frequency modulation systems (FSK, FMCW), the operating frequency range includes the range from the lowest frequency to the highest frequency tuned over all carrier frequencies of the device.

1.4.16. Peak power

Peak power is the maximum instantaneous power of the EUT.

1.4.17. Permitted frequency range

Permitted frequency rangeare the frequency ranges in which the device is permitted to operate.

1.4.18. Power envelope

Power envelope is the power delivered to the transmitter antenna during transmission, taken at the top of the modulation envelope under normal operating conditions.

1.4.19. Power spectral density

Power spectral density is the ratio of the power to the bandwidth used by the radio measurement.

1.4.20. Pulse radar

Pulse radar is a radar that determines the distance (range) based on the transmission time of short pulse radars and they are not frequency modulated.

1.4.21. Radar Cross Section (RCS)

Radar crosssection is the cross-sectional area of ​​a reflecting sphere that will produce the reflected intensity to the projected object.

1.4.22. Scanning (steerable) antenna

Scanning antenna is a directional antenna that can move its beam along a predetermined spatial path.

NOTE: Scanning can be performed by mechanical, electronic means or a combination of both. The antenna band width may be constant or vary with steering angle, depending on the steering method.

1.4.23. Second (2nd) harmonic

2nd harmonic is a harmonic whose corresponding frequency is twice the fundamental frequency (e.g. 48 GHz for a 24 GHz device).

1.4.24. Ground based vehicle

Ground based vehicle includes, but is not limited to, passenger cars, buses, trucks, railway vehicles, trams, boats, construction vehicles, and aircraft in transit.

1.4.25. Occupied bandwidth

Occupied bandwidth is the width of the frequency band over which the mean power is radiated at frequencies lower than the lower bound and above the upper bound of that band which are equal to a given percentage /2 of the total mean power of that emission.

Unless otherwise specified, the β/2 value is chosen to be 0.5 %.

1.4.26. Integral antenna

Integral antenna is an antenna designed to be connected to device without a standard connector and which is considered part of the device.

1.5. Symbols

λ                            Wavelength

B                            Bandwidth (pulse)

d                            Maximum diameter of antenna aperture

dB                          Decibel

d_FF                         Far field distance

D                            Scanning antenna load factor

E                            Electric field strength

f_c                            Carrier frequency

f_H                           Highest frequency

f_L                                              Lowest frequency

F                            Permitted frequency bandwidth

F₁                           Low margin between OOB domain and pseudo-domain

F₂                           High margin between OOB domain and pseudo-domain

BW_o                    Observation bandwidth

P_CORR                     Corrected measured power relative to RBW

P_MEASURED               Measured power

RBW                      Resolution Bandwidth

RBW_REF                 Reference Resolution Bandwidth

RBW_MEASURED        Resolution bandwidth used for measurements

t_o                         Observation time

1.6. Abbreviations

AC                         Alternating Current

BW                        Bandwidth

CEPT                     European Conference of Postal and Telecommunications administrations

CISPR                   Comité International Spécial des Perturbations Radioélectriques

CW                        Continuous Wave

DC                         Direct Current

e.i.r.p.                    equivalent isotropically radiated power

e.r.p.                      equivalent radiated power

EC                         European Commission

ECC                       Electronic Communications Committee

EMC                      Electro Magnetic Compatibility

ERC                       European RadiocommunicationCommittee

EUT                       Equipment UnderTest

FFT                       Fast Fourier Transform

FMCW                  Frequency Modulation Continuous Wave

FSK                       Frequency Shift Keying

IF                           Intermediate Frequency

LNA                      Low Noise Amplifier

OBW                     Occupied Bandwidth

OOB                      Out-Of-Band

PSD                       Power Spectral Density

RBW                     Resolution Bandwidth

RCS                       Radar Cross Section

RE-D                     Radio Equipment Directive

RF                         Radio Frequency

RMS                      Root Mean Square

RR                         ITU-R Radio Regulations

Rx                          Receiver (Receive)

SNR                       Signal to Noise Ratio

SRD                       Short Range Device

Tx                          Transmitter

VBW                     Video Bandwidth

VSWR                   Voltage Standing Wave Ratio

2. TECHNICAL SPECIFICATIONS

2.1. Environmental conditions

The technical requirements in this regulation apply to the operation of the device under the environmental conditions declared by the manufacturer.

The device shall comply with all specifications of this regulation for the duration of its operation within the amplitude limits of the stated environmental conditions.

The normal and severe test conditions are defined in A.4.3 and A.4.4 of Appendix A.

2.2. General provisions

2.2.1. General information

In this section, general considerations for radar testing for ground based vehicle applications in the frequency range 76 GHz - 77 GHz are given.

Measurements include measurements for transmitters and integrated transceivers.

All operating bands of the device (see 2.3.1) shall be declared by its manufacturer.

When the device has multiple operating bandwidths, a sufficient number of operating bandwidths shall be selected for the test, including lower and upper limits of operating frequency, minimum and maximum bandwidth.

An EUT with a scanning/steerable antenna is an EUT with an electrically or mechanically adjustable transmit antenna directional scheme.

2.2.2. Desired performance criteria

The desired performance criterion is when the properties of the EUT are shown with a given target at a certain distance. The EUT type considered here is often tailored for specific applications so no individual desired performance criteria can be defined here.

Therefore:

• The relevant attributes (e.g. presence, range, relative speed, azimuth) shall be declared by the manufacturer;

• Target type and RCS and distance shall be declared by the manufacturer.

2.2.3. Fixed antenna and scanning antenna

Provisionsin A.3.5 of Appendix A shall apply.

2.3. Requirements for the transmitter

The requirements below apply to all EUTs.

2.3.1. Operating frequency range

2.3.1.1. Definition

It is the transmitter frequency range of the device. Operating frequency range of the device is determined by the lowest frequency (f_L) and the highest frequency (f_H) when it is enclosed by the power envelope.

2.3.1.2. Limit

The upper and lower limits of the operating frequency range shall meet the following conditions:

• f_H77GHZ.

• f_L 76 GHz.

2.3.1.3. Test method

The measurement method is specified in 3.1.1.

2.3.2. Mean power

2.3.2.1. Definition

Meane.i.r.p. of EUT, at a particular frequency is the result of the mean power delivered to the antenna multiplied by the gain of the antenna in a given direction relative to an isotropic antenna, measured under specific conditions.

Maximum meane.i.r.p. is the mean radiated power at maximum (usually in the direction of maximum gain of the antenna) under specific measurement conditions.

This power shall be measured in the operating frequency ranges (see 2.3.1). The value is in dBm.

2.3.2.2. Limit

Mean power shall not exceed the limit given in Table 2.

Table 2 - Mean power

For fixed-direction scanning antennas to be measured with limited scan (A.3.5 of Appendix A), the mean power is calculated from the P_MEASURED measurement results as shown in Table 3 below.

Table 3 - Mean power calculation (fixed-direction scanning antenna)

2.3.2.3. Test method

The measurement method is specified in 3.1.2.

2.3.3. Peak power

2.3.3.1. Definition

Peak e.i.r.p. is the highest instantaneous radiated power of the device. It is measured within the permitted operating frequency range.

2.3.3.2. Limit

Peak power of the EUT with fixed beam or scanning antenna shall not be more than 55 dBm.

2.3.3.3. Test method

The measurement method is specified in 3.1.3

2.3.4. Unwanted emissions in the out-of-band domain

2.3.4.1. Definition

Out-of-band emissions are those on one or more frequencies outside the required bandwidth that result from modulation, but do not include spurious emissions.

The measurement results of f_H and f_L (see 3.1.1) are used to determine the operating bandwidth of the device.

The operating bandwidth (f_H - f_L) values are used to determine the out-of-band emission domain and spurious emission domain.

Spurious emissions are those on one or more frequencies outside the required bandwidth and the value of which can be reduced without affecting the transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation components and frequency conversion components, but do not include out-of-band emissions.

According to CEPT/ERC 74-01 recommendation and ITU-R SM.329-12recommendation, the boundary between the out-of-band emission domain and the spurious emission domain is ± 250 % of the required bandwidth from the central emission frequency. Out-of-band emissions and spurious emissions are determined based on a measurement of the mean power spectral density under normal operating conditions.

Figure 1 - Overview of OOB/spurious emission dependence on OBW

The boundary limit is determined as follows:

fc= (f_L+f_H)/2

F1 = fc - (2.5*(f_H - f_L))

F2 = fc + (2.5*(f_H-f_L))

This calculation indicates the determination of the out-of-band and spurious emission domain boundaries, which will be greater than/less than the maximum value in the permitted operating frequency range.

2.3.4.2. Limit

The calculated RMS radiated power spectral density in the out-of-band domain (between F₁ to f_L and f_H to F₂) shall not be greater than the values given in Table 4.

Table 4 - Radiation limits in the out-of-band domain

- The f_L and f_H values are the results of the operating c range measured in 2.3.1.3.

- Values F₁ and F₂ are calculated results in 2.3.4.1.

2.3.4.3. Test method

The measurement method is specified in 3.1.4

2.3.5. Unwanted emissions in the pseudo-domain

This provision applies to all EUTs.

2.3.5.1. Definition

According to the definition in 2.3.4.1.

2.3.5.2. Limit

The effective radiated power of any spurious emissions shall not exceed the values given in Table 5.

Table 5 - Radiated spurious emission values

2.3.5.3. Test method

The measurement method is specified in 3.1.5.

2.4. Requirements for the receiver

2.4.1. Receiver spurious emissions

The receiver spurious emission test provisions apply to all modes except transmission.

NOTE:On the other hand, the receiver spurious emissions are measured as part of the transmitter spurious emissions, see 2.3.5.

2.4.1.1. Definition

Receiver spurious emissions are those on any frequency when the device is in receive mode. Therefore, the test for receiver spurious emissions is applicable only when the device can operate in receive-only mode or as a receive-only device.

2.4.1.2. Limit

The effective radiated power of any narrowband receiver spurious emissions shall not exceed the values given in Table 6.

Table 6 - Narrowband receiver spurious emission limits

Broadband receiver spurious emissions shall not exceed the values given in Table 7.

Table 7 - Broadband receiver spurious emission limits

2.4.1.3. Test method

The measurement method is specified in 3.2.1.

2.4.2. Receiver in-band, out-of-band and remote control signals

This provision applies to all EUTs.

2.4.2.1. Definition

The ability of the receiver to operate as intended when in-band, out-of-band and remote-band unwanted signals are occurring.

2.4.2.2. Limit

In the presence of the unwanted signals defined in Table 8, the EUT will achieve the desired performance criteria (see 2.2.2).

The transmitter unwanted signal may transmit a continuous wave signal at specific frequencies, as given in Table 8.

Table 8 - Unwanted signals for sensors in the frequency range 76-77 GHz

2.4.2.3. Test method

The measurement method is specified in 3.2.2.

3. MEASUREMENT METHODS

3.1. Test for transmitter

3.1.1. Operating frequency range

This measurement is made under normal and extreme test conditions. The spectrum analyzer is set to receive and measure mode as follows (see Appendix B).

a) Start frequency: The frequency that is lower than the lower boundary of the permitted frequency range.

b) Stop frequency: The frequency that is higher than the upper boundary of the permitted frequency range.

c) Resolution bandwidth: 1 MHz.

c) Video bandwidth:  3 MHz.

d) Detector mode: RMS (see ITU-R SM.328-11recommendation).

e) Display mode: Max hold.

f) Averaging time: ≥  1ms per sweep point.

Approximately 99% of the OBW is used to determine the operating frequency range.

• f_H: the frequency of the upper marker from OBW.

• f_L: the frequency of the lower marker from OBW.

• Center frequency f_c: f_c= (f_H +f_L)/2.

In addition, the results recorded from the mean power measurement described in 3.1.2 may be used.

3.1.2. Mean power

This measurement is made under normal and extreme test conditions.

There are three measurement methods used to measure mean power. Each method is applicable to all EUTs.

3.1.2.1. Measurement methodusing spectrum analyzer

The spectrum analyzer is set to receive and measure mode as follows (measurement setup is described in Appendix B):

a) Start frequency: The frequency that is lower than the lower boundary of the permitted frequency range.

b) Stop frequency: The frequency that is higher than the upper boundary of the permitted frequency range.

c) Resolution bandwidth: 1 MHz.

c) Video bandwidth: VBW  RBW.

d) Detector mode: RMS.

e) Display mode: Clear write.

f) Averaging time: Greater than one cycle time of the EUT.

g) Sweep time: (Averaging time) X (Number of sweep points).

The channel power is used to calculate the mean power. Boundaries for the calculation need to be defined. This boundary is usually the operating frequency range.

3.1.2.2. Measurement method using mean power meter

The power meter shall be connected to the measuring antenna. The frequency correction factor shall be included in the calculation. The power meter shall be a true RMS power meter (see F.2 of Appendix F). The measurement time shall be equal to or longer than the cycle time of the EUT.

3.1.2.3. Measurement method using peak power meter

The power meter shall be connected to the measuring antenna. The frequency correction factor shall be included in the calculation. The power meter shall be a true peak power meter (see F.2 of Appendix F). The measurement time shall be sufficiently long compared with the cycle time of the EUT.

The mean power is obtained by multiplying the peak power measured by the meter by the power duty cycle.

Mean power = (Measured peak power) X (Power duty cycle)

Where: Power duty cycle is the percentage of the EUT in the On state over the total cycle time of the EUT.

3.1.3. Peak power

This measurement is made under normal and extreme test conditions.

There are three methods used to measure peak power. Clause 3.1.3.1 (measurement method using spectrum analyzer): The settings depend on the EUT frequency sweep rate. Clauses 3.1.3.2 and 3.1.3.3 (measurement method using power meter) are independent of the EUT frequency sweep rate.

3.1.3.1. Measurement method using spectrum analyzer

The spectrum analyzer is set to receive and measure mode as follows (see Appendix B):

a) Start frequency: The frequency that is lower than the lower boundary of the permitted frequency range.

b) Stop frequency: The frequency that is higher than the upper boundary of the permitted frequency range.

c) Resolution bandwidth: 1 MHz with a scan frequency less than 1,000 MHz/ms.

NOTE: For EUTs with higher frequency sweep rates, the RBW shall be increased until a stable peak power index is obtained.

c) Video bandwidth: VBW ≥ RBW.

d) Detector mode: Peak or auto peak detector.

e) Display mode: Max hold.

f) Averaging time: Greater than one cycle time of the EUT.

g) Sweep time: (Measured averaging time) X (Number of sweep points).

The peak power to be sought is the maximum value and is recorded in the test results.

3.1.3.2. Measurement method using mean power meter

The power meter shall be connected to the measuring antenna. The frequency correction factor shall be included in the calculation. The power meter shall be a true RMS power meter (see F.2 of Appendix F).

The measurement time shall be sufficiently long compared with the cycle time of the EUT.

The peak power is obtained by dividing the mean power measured by the meter by the power duty cycle.

Peak power = (Measured mean power)/(Power duty cycle)

Where: Power duty cycle is the percentage of the EUT in the On state over the total cycle time of the EUT.

3.1.3.3. Measurement method using peak power meter

The power meter shall be connected to the measuring antenna. The frequency correction factor shall be included in the calculation. The power meter shall be a true peak power meter (see F.2 of Appendix F).

3.1.4. Unwanted emissions in the out-of-band domain

This measurement is made under normal test conditions.

A spectrum analyzer is used as a measuring receiver. The bandwidth of the measuring receiver shall be in accordance with CISPR 16. In order to obtain the required sensitivity, a narrower resolution bandwidth may be required, this shall be stated in the test results and the results shall be narrowed down as specified in A.5 of Appendix A.

In the case of an EUT with multiple modes of operation, only the highest mode of the peak e.i.r.p. (see 3.1.3) should be measured.

Measurements shall be made over the frequency ranges of the OOB and the pseudo-domains specified in 2.3.4.

a) Start frequency: See 2.3.4.2

b) Stop frequency: See 2.3.4.2

c) Resolution bandwidth:

- From 30 MHz to 1 GHz: 100 kHz.

-Above 1 GHz: 1 MHz.

c) Video bandwidth: ≥ 3 MHz.

d) Detector mode:

- From 30 MHz to 1 GHz: Quasi-peak;

-Above 1 GHz: RMS.

e) Display mode: Clear write.

f) Averaging time: Greater than one cycle time of the EUT.

g) Sweep time: (Averaging time) X (Number of sweep points).

NOTE: The number of sweep points should be higher than the span of the spectrum analyzer divided by the RBW.

The spectral curve measured at the spectrum analyzer is recorded over an amplitude range of approximately 35 dB. No measurement is required when the mean power spectral density is below -40 dBm/MHz (e.i.r.p.) in the frequency range above 1 GHz.

Mean power spectral density measurements below -40 dBm/MHz (e.i.r.p.) are not required for a range above 1 GHz.

The test site, described in Appendix B, fully meets the requirements of the particular frequency range used in the measurement. The bandwidth of the measuring receiver shall be set to an appropriate value for accurate measurement of unwanted emissions. This bandwidth shall be recorded in the test results. For frequencies above 40 GHz, a frequency reducer as described in Figure 2 shall be used. An internal oscillator shall be used to reduce the received signal frequency with phase noise better than -80 dBc/Hz at 100 kHz offset. The frequency of the internal oscillator shall beselected so that the signal received after the frequency reduction is within the operating frequency range of the spectrum analyzer, while maintaining adequate IF response bandwidth to capture the full spectrum of the signal.

For spurious emission measurements, a LNA (low noise amplifier) ​​should be used prior to connection to a spectrum analyzer to achieve the required sensitivity.

Figure 2 - Test setup diagram of out-of-band radiation and spurious emissions

3.1.5. Unwanted emissions in the pseudo-domain

See provisions in 3.1.4 (where: Start frequency and Stop frequency shall comply with 2.3.5.2 when the spectrum analyzer is set up to test this criterion).

3.2. Test for the receiver

3.2.1. Receiver spurious emissions

This measurement is made under normal test conditions.

3.2.1.1. General provisions

Separate spurious emission measurements need not be made for the EUT where the receiver is co-located and operating simultaneously with the transmitter. In this case, the provisions of 3.1.4 shall apply to spurious and out-of-band emissions.

In all other cases, the following shall apply:

a) The test site, as described in Appendix B, meets the requirements of the specific frequency range used in the measurement. The test antenna shall be initially oriented for vertical polarization and connected to the measuring receiver. The measuring receiver shall be a spectrum analyzer with the setting as specified in 3.1.4.

The measuring receiver shall be placed on the support in its reference position.

b) The frequency of the measuring receiver shall be tuned within the frequency range defined in the relevant harmonized standard. The frequency of each component of the spurious emissionshall be noted. If the test site is disturbed by radiation coming from outside, a search for this qualitative value can be performed in a shielded room with a reduced distance between the transmitter and the test antenna.

c) At each frequency at which a component has been detected, the measuring receiver shall be tuned and the test antenna raised or lowered over the specified range of heights until the maximum signal level is detected on the measuring receiver.

d) The receiver shall be rotated up to 360° in the vertical axis, for maximum signal reception.

e) The test antennas shall be raised or lowered again within the specified range of heights until the maximum level is obtained. This level shall be recorded.

f) The replacement antenna shall replace the receiving antenna in the same position and in the vertical polarization. It shall be connected to the signal generator.

g) At each frequency at which a component is detected, the signal generator, replacement antenna and measuring receiver shall be tuned. The test antenna shall be raised or lowered within the specified range of heights until the maximum signal level is obtained on the measuring receiver. The value of the signal generator gives the same value of signal on the measuring receiver as in step e). After tuning the gain of the replacementantenna and the loss due to cable, this value is the spurious emission component at this frequency.

h) The frequency and value of each measured spurious emission and the bandwidth of the measuring receiver shall be recorded in the test results.

i) The measurements in b) to h) shall be repeated with the test antenna oriented towards horizontal polarization.

3.2.1.2. Test

To measure spurious emissions, the spectrum analyzer is set to receive and measure mode as follows:

a) Resolution bandwidth: 100 kHz.

c) Video bandwidth: 100 kHz.

d) Detector mode: Positive peak.

e) Averaging value: Off.

f) Span: 100 MHz.

g) Sweep time: 1 s.

h) Amplitude: Tune in the middle of the amplitude region.

To measure emissions that exceed 6 dB below the specified limit, the resolution bandwidth shall be switched to 30 kHz and the width tuned accordingly. If the level change is no more than 2 dB, it is narrowband emission; the observed value shall be recorded in the test results. If the level change is greater than 2 dB, it is a broadband emission and the observed value shall be recorded in the test results.

If a broadband emission measurement method is used, this shall be recorded in the test results.

NOTE: The main spectrum of the equipment under test can saturate the input circuits of the spectrum analyzer and thereby cause a "spurious emission" specter signal. The "spurious emission" specter can be distinguished from the real signal by increasing the input loss by 10 dB. If the spurious signal disappears, it is a "spurious emission" specter and should be ignored.

3.2.2. Receiver in-band, out-of-band, and remote control signals

This measurement is made under normal test conditions.

3.2.2.1. Introduction

This section presents a measurement method to check the EUT's ability to handle unwanted signals during normal operation.

3.2.2.2. Measurement setting

The target type (RCS), position and distance relative to the EUT are defined in the relevant harmonized standard. The source of the unwanted signal is located within 3 dB at the center operating frequency of the RX. See 3.2.2.4 for the unwanted signal specification.

The desired performance criteria are given in the relevant harmonized standard.

3.2.2.3. Test procedure

• The target and source of the unwanted signal shall be specified as defined in 3.2.2.2.

• The EUT shall be ON. The fulfillment of the relevant desired performance criteria shall be verified.

• The unwanted signal generator shall be ON at less than 20 dB below the level of the unwanted signal specified in 3.2.2.4.

• To simulate real use cases, the level of the unwanted signal shall be increased in 5 dB increments until the desired performance criterion is not met or the level of the unwanted signal specified in 3.2.2.4 is achieved. The unwanted signal shall be held at each source step for at least 5 s. The measurement procedure shall be repeated for each unwanted signal generator frequency mode, as defined in 3.2.2.4.

3.2.2.4. Unwanted signal specification

The unwanted signal generator may transmit signals at specific frequencies, as described in the relevant harmonized standards.

4. MANAGEMENT PROVISIONS

4.1. Radar equipment operating in the frequency range 76 GHz to 77 GHz within the scope of regulation in clause 1.1 shall comply with the provisions of this regulation.

4.2. The test of specifications of this regulation in order to make announcement of regulation conformity shall comply with current provisions. Organizations and individuals are allowed to use measurement/test results of designated domestic testing laboratories, or recognized foreign testing laboratories, or domestic and foreign testing laboratories accredited in accordance with ISO/IEC 17025, or manufacturer's test/test results.

5. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

The relevant organizations and individuals are responsible for declaring the conformity of equipment within the scope of this regulation and subject to inspection by state management agencies in accordance with current provisions.

6. IMPLEMENTATION ORGANIZATION

6.1. The Department of Telecommunications, the Department of Radio Frequency and the Departments of Information and Communications are responsible for organizing the implementation, guidance and management of equipment under the scope of this regulation.

6.2. In case the provisions mentioned in this regulation are changed, supplemented or replaced, the provisions of the new document shall apply.

6.3. In the process of implementing this regulation, if any problem arises, relevant organizations and individuals should report it in writing to the Ministry of Information and Communications (Department of Science and Technology) for guidance and settlement./.

Appendix A
(Normative)
General conditions
 

A.1. Overview

In this section, all general provisions for the measurement of short range radar equipment are given. These provisions and requirements relate to the arrangement of the equipment under test (see A.2), requirements for the EUT (see A.3), general test conditions (see A.4), reference bandwidth for measurements (see A.5), interpretation of test results (see A.6) and test results (see A.7).

A.2. Equipment information

The following equipment information may be required to make measurements and shall be provided by the manufacturer, such as:

• Environmental conditions and relevant harmonized standards;

• Rated voltage supplied to stand-alone radio equipment or rated voltage supplied to main or combined equipment in the case of attached radio equipment;

• Type of technology/modulation used for the equipment (e.g. pulse, pulse Doppler, FMCW, etc.);

• For all modulation schemes, modulation parameters should be provided: e.g. modulation time, pulse sweep time, modulation bandwidth;

• High and low power modes;

• Equipment power cycle;

• Operating frequency range of the equipment (see 3.1.1);

• Normal installation direction of the EUT;

• Antenna polarization for both transmitting and receiving antennas;

• Antenna emission direction, as well as antenna width, horizontal and vertical 3 dB points for both transmitting and receiving antennas;

• Details of any antenna switchingor electrical or mechanical sweep. Where such features are available, information on whether they can be disabled for test purposes should also be clarified;

• Desired temperature range, including the required start-up time of the EUT (see A.4.4.1.2.);

• Information of equipment functionality to establish desired performance criteria (see 3 2.2).

A.3. Requirements for EUT

A.3.1. EUT version and configuration

The test can be performed on equipment in production or on equivalent versions of equipment.

NOTE: It is the responsibility of the manufacturer to ensure that the equipment put into service meets the relevant requirements of applicable legislation, including RE-D.

If an equipment has optional features that are deemed not to directly affect RF parameters, measurements need only be made on the equipment configured with the worst case combination of features and declared by the manufacturer.

A.3.2. Presentation

The manufacturer shall provide all facilities necessary to operate the EUT during the test.

A.3.3. Multiple operating bandwidths

All equipment operating bandwidths shall be declared by the equipment manufacturer (see A.2).

When equipment has multiple operating bandwidths, a sufficient number of operating bandwidths shall be selected for the test, including lower and upper limits of operating frequency, minimum and maximum bandwidth.

A.3.4. Modulation requirements during test

Modulation of the EUT during test shall be sufficient for the normal use of the equipment. The manufacturer shall use the method of equipment operation for the highest performance of the transmitter, in accordance with the requirements for measuring the highest power transmission that will be in service, and shall ensure that:

• The transmission line is continuous throughout the measurement;

• The transmission sequence can be exactly repeated. For transmitters with multiple combined multi-modulation schemes, it is necessary to check each scheme.

A.3.5. Requirements in case the EUT uses a scanning antenna

A.3.5.1. Classification

For the purposes of this regulation, EUTs are divided into three classes according to the type of transmitting antenna:

• Fixed beam: In this class of EUT, the antenna radiation pattern is constant and the direction of transmission is fixed relative to the EUT's housing.

• Constant pattern: In this class of EUT, the antenna radiation pattern is constant and the direction of emission varies with time. Scanning emission direction changes the fixed angular speed.

• Variable model: This class of EUT includes all classes that are not fixed model or constant model. The antenna radiation pattern varies with time and/or direction or scanning at a variable rate. For the purposes of the above classification, when it is fixed and constant within 1 degree or 1 %, it is considerednormal operation.

NOTE 1: The classification depends only on the type of the transmitting antenna.

NOTE 2: In general, the mechanical scanning antenna shall be the constant model and the electrical scanning antenna shall be the variable model.

NOTE 3: Although the terms beam and model are used sparingly, the same considerations and classification apply to EUTs with multiple beams.

A.3.5.2. Measurement of EUT fixed beam

No special considerations apply. Measurements shall be made in the direction of maximum antenna gain, unless otherwise specified.

A.3.5.3. Measurement of EUTconstant model

Scanning may be obstructed and measurements made on the emitted beam unless otherwise specified. The parameters of the EUT operating in normal mode can be calculated based on knowledge of the antenna. The manufacturer shall declare the relevant parameters of the antenna.

A.3.5.4. Measurement of EUT variable model

Measurements shall be made with the scanning antenna. It may be necessary to perform a set of measurements on the whole sphere or the half sphere. For radiated energy measurements (e.g. peak power, mean power, duty cycle), the direction chosen is the one that gives the maximum value.

A.4. Test conditions

A.4.1. Introduction

Measurements shall be made under normal test conditions. For certain requirements it may be necessary to carry out the measurement under extreme conditions.

The test conditions and procedures shall comply with provisions in A.4.2. toA.4.4.

A.4.2. Power supply

During the test, the equipment power supply shall be replaced by a test power capable of producing the normal test voltage as specified in A.4.3.2 and the extreme test voltage as specified in A.4.4.2. The internal impedance of the test power shall be low enough that its influence on the test results is negligible. For test purposes, the voltage of the power supply shall be measured at the inputs of the equipment.

For battery operated equipment, the battery may be removed and the test power source applied as close to the battery terminals as possible.

During the measurements, the supply voltage shall be maintained within ±1 % of the voltage at the beginning of each test. The value of this tolerance is important for power measurements; using smaller tolerances shall provide better measurement uncertainty values.

A.4.3. Normal test conditions

A.4.3.1. Normal temperature and humidity

The normal temperature and humidity conditions for the test shall be a suitable combination of temperature and humidity within the following ranges:

Temperature:+15 °C to +35 °C;

Relative humidity: 20 % to 75 %.

When measurements cannot be made under these conditions, the ambient temperature and relative humidity should be stated in the measurements and this shall be recorded in the test results.

Actual values ​​in the measurements shall be recorded in the test results.

A.4.3.2. Normal power supply

A.4.3.2.1. Supply voltage

The supply voltage connected to the measuring equipment under test shall be the rated voltage. Within the scope of this regulation, rated voltage is the voltage at which the equipment is designed to operate.

The test voltage source frequency corresponding to the AC voltage shall be between 49 Hz and 51 Hz.

A.4.3.2.2. Lead-acid battery power source used in vehicle

When radio equipment is intended for normal operation from the lead-acid battery power source used in the vehicle, the normal test voltage shall be 1.1 times the rated voltage of the battery (6 V, 12 V, etc.).

A.4.3.2.3. Other power sources

Where the equipment under test uses other power sources or batteries (primary or secondary), the rated test supply voltage shall be declared by the manufacturer. This shall be recorded in the test results.

A.4.4. Extreme test conditions

A.4.4.1. Extreme temperatures

A.4.4.1.1. Test procedure at extreme temperatures

Before measurements are made, the equipment shall reach thermal equilibrium in the test chamber. The equipment shall not be switched off during the temperature stabilization.

If the thermal equilibrium is not checked by measurements, the temperature stabilization time is at least one hour, or such time period as may be determined by an accredited measuringlaboratory. The sequence of measurements shall be chosen, and the humidity in the test chamber shall be controlled so that excessive condensation does not occur.

A.4.4.1.2. Extreme temperature range

For extreme temperature measurements, they shall be made according to the procedures specified in Appendix B, at temperatures above and below one of the following ranges as declared by the manufacturer:

Class I temperature: -10 °C to +55 °C.

Class II temperature: -20 °C to +60 °C.

Class III temperature: -40°C to +70°C.

The manufacturer may specify a wider temperature range than the minimum above. The test results shall state the temperature range used.

A.4.4.2. Extreme test supply voltage

A.4.4.2.1. Main voltage

Extreme test voltages for equipment connected to AC mains shall be the rated voltage with a tolerance of ± 10 %.

A.4.4.2.2. Other power sources

For equipment using other power sources, or capable of operating from a variety of power sources, the extreme test voltage shall be that declared by the manufacturer. They shall be recorded in the test results.

A.5. Reference bandwidth of the measuring receiver

In general, the resolution bandwidth of the measuring receiver (RBW) shall be equal to the reference bandwidth (RBW_REF) given in Table A.1.

Table A.1 - Reference bandwidth of measuring receiver

To improve measurement accuracy, sensitivity and efficiency, RBW may differ from RBW_REF. When RBVH_measuredis < RBW_REF, the result will be integrated on RBW_REF for example by formula (1)

Where:

- P (i) are the samples measured with RBW_MEASURED;

- n is the number of samples in RBW_REF;

- P_CORR is the corresponding value at RBW_REF.

When RBW_measuredis > RBW_REF, the result for broadband emission will be normalized to the bandwidth ratio according to formula (2).

P_CORP = P_MEASURED +10 log (RBW_ref/RBW_MEASURED) (2)

Where:

- P_MEASURED is the measured value at a wider measurement bandwidth than RBW_MEASURED;

- P_CORR is the corresponding value at RBW_REF.

For discrete emissions, determined at a narrow peak with at least 6 dB above average within the measurement bandwidth, the overhead correction is applied while the integration on the RBW_REF is still used.

A.6. Interpretation of test results and measurement uncertainties

A.6.1. Overview

The interpretation of results for the measurements described in this regulation is as follows:

1) The measured value relative to the corresponding limit shall be used to decide whether the equipment meets the requirements of this regulation;

2) The measurement uncertainty value for measurements of each parameter shall be recorded in the test results;

3) The measurement uncertainty value shall be recorded at any position, for each measurement, equal to or below the data in Table A.2, and the procedure specified in A.6.3 shall be used.

For test methods according to this regulation, the measurement uncertainty data shall be calculated according to the instructions given in ETSI TR 100 028 and shall correspond to the expansion factor (coverage factor) k = 1.96 or k = 2 (providing 95 % and 95.45 % confidence levels, respectively, in the case where the characteristic distribution for measurement uncertainty is normal (Gaussian distribution)).

Table A.2 is based on such expansion factors.

Table A.2 - Maximum permissible measurement uncertainty

A.6.2. Maximum permissible measurement uncertainty

In the event that the measurement uncertainty exceeds the limits in Table A.2, the provisions of A.6.4 shall apply.

A.6.3. Measurement uncertainty equal to or less than the maximum permissible uncertainty

The interpretation of results when comparing measured values ​​with specification limits shall be as follows:

a) When the measured value does not exceed the limit value, the equipment under test meets the requirements of the relevant harmonized standard.

b) When the measured value exceeds the limit value, the equipment under test does not meet the requirements of the relevant harmonized standard.

c) The measurement uncertainty is calculated by the test technician who performs the measurement and shall be recorded in the test results.

d) The measurement uncertainty calculated by the test technician may be the maximum value within a range of measured values, or it may be the measurement uncertainty for a particular measurement that has not been made. The method used shall be recorded in the test results.

A.6.4. Measurement uncertainty greater than the maximum permissible uncertainty

The interpretation of results when comparing measured values ​​with specification limits shall be as follows:

a) When the measured value plus the difference between the measurement uncertainty calculated by the test technician and the maximum permissiblemeasurement uncertainty does not exceed the limit value, the equipment under test meets the requirements of the relevant harmonized standard.

b) When the measured value plus the difference between the measurement uncertainty calculated by the test technician and the maximum permissible measurement uncertainty exceeds the limit value, the equipment under test does not meet the requirements of the relevant harmonized standard.

c) The measurement uncertainty is calculated by the test technician who performs the measurement and shall be recorded in the test results.

d) The measurement uncertainty calculated by the test technician may be the maximum value within a range of measured values, or it may be the measurement uncertainty for a particular measurement that has not been made. The method used shall be recorded in the test results.

A.7. Test results

The test results shall contain all necessary and relevant information to assess compliance with the essential requirements listed in Appendix A of the relevant harmonized standard (see ETSI EN 301 091-1, ETSI EN 301 091-2, ETSI EN 301 091-3, ETSI EN 302 264 and ETSI EN 302 858).

Appendix B
(Normative)
Measurement setup and measurement procedure
 

B.1. Introduction

In general, there is a difference between making conductivity and RF radiation measurements. However, for EUTs covered by this regulation, it should be noted that no RF conductivity measurements are made.

The following sections describe general test environment settings for short range radar radiation measurements.

B.2. Initial measurement steps

The measurement procedure shall be planned using the information provided by the manufacturer (see A.2 of Appendix A).

The measuring receiver settings shall be selected based on the signal description provided, in order to ensure that the maximum values ​​of peak power and mean PSD are obtained. This is especially important for receivers that measure scan frequencies (spectrum analyzers) and signals that have changes in time and/or frequency and/or direction. It is recommended that the initial signal be observed with both peak and mean measurement modes across its bandwidth, in order to confirm the description and establish where the maximum values ​​are present. This will allow further measurements to be made with a narrower RF. In case there is any doubt about the effect of the frequency scan, a measurement at an RF (zero span) will provide validation of this.

B.3. Radiation measurement

B.3.1. Overview

The test area, test antenna and replacement antenna used for radiation measurements shall be described as in Appendix C. For instructions for use of the radiometric positions, see B.3.2. For instructions for use of the standard measuring positionsused for radiation measurements, see Appendix D.

All efforts should be made to clearly demonstrate that the emissions from the EUT transmitter do not exceed the specified levels, with the transmitter in the far field. To the extent practicable, the radio equipment under test shall be measured at the distance specified in B.3.2.4 and with the specified measurement bandwidth. However, in order to obtain an appropriate signal-to-noise ratio in the measuring system, the radiation measurements may have to be made at distances smaller than those specified in B.3.2.4 and/or reduced measurement bandwidths. The modified measurement configuration shall be indicated in the test results, together with a note why the signal levels are relevant to the measurement at the distance used or with the measurement bandwidth used for correct detection by measuring equipment and calculation of compliance proof.

In cases where it is not possible to further reduce the measurement bandwidth (due to common test equipment limitations or difficulty in converting readings used by a measurement bandwidth into bandwidths used by the limits given in the relevant harmonized standard, the required measuring distance will be so short that the radio equipment is not clearly located in the far field), the measurement results will show this fact, the measuring distance and bandwidth, near-field/far-field distances for measurement setup, measured radio equipment emissions, achievable background noise, and associated frequency ranges shall be used.

B.3.2. Instructions for use of the radiation test area

B.3.2.1. Introduction

This section details the procedures, test equipment arrangements and verification to be performed before any radiation test is performed.

B.3.2.2. Inspection of the measurement area

Tests should not be performed on an area that does not have a valid certificate of authenticity. The verification procedures for the different types of measurement areas described in Appendix C (i.e. anechoic chamber and ground plane anechoic chamber) are given in the relevant sections of ETSI TR 102 273 or equivalent.

B.3.2.3. Hanger

Where necessary, a hanger of minimum dimensions shall be provided for mounting the EUT on the turntable. This hanger shall be constructed from a low conductivity, relatively low dielectric constant (i.e. less than 1.5) material such as expanded polystyrene, softwood, etc.

B.3.2.4. Length range

The length range for all types of test media shall be sufficient to permit measurement in the far field of the EUT, i.e. it shall be equal to or greater than:

Where:

- d₁ is the maximum size of the EUT/dipole after replacement (m);

-d₂ is the maximum size of the test antenna (m);

- λ is the wavelength of the test frequency (m).

This formula keeps the error due to near-field effects greater than 0.25 dB on the antenna orientation, which may be required to accurately measure the antenna radiation pattern. However, such high accuracy is not required for compliance purposes.

In addition, for mm-waves, the resulting distance can be so large that the measured power is close to the detector sensitivity level and/or the measurement in the test chamber becomes impractical. Therefore, the following reduced far-field distances are considered.

Table B.1 - Far-field measuring distances

It should be noted in the test results that these conditions are met so that any additional measurement uncertainty can be included in the results.

NOTE 1:For a completely anechoic chamber, no part of the EUT shall, at any angle of rotation of the turntable, be outside the "quiet zone" of the test chamber at the rated frequency of the test.

NOTE 2: "Quiet zone" is a volume in an anechoic (without ground plane) chamber in which the specified performance has been demonstrated by testing, or is guaranteed by the designer/ manufacturer. The specified performance is usually the reflectivity of the absorption plates or a directly related parameter (e.g. signal uniformity in amplitude and phase). However, it should be noted that the defined levels of the quiet zone tend to vary.

B.3.2.5. Preparation of test site

Cables for both ends of the measuring area shall be oriented horizontally from the measuring area for a minimum of 2 m and then allowed to drop vertically and outward through the ground plane or screen (if appropriate) to the test equipment. Precautions should be taken to minimize absorption on these conductors (e.g. coating with ferrite beads or other loads). The directional cables and their sheath should be identical to the tested setup.

Calibration data for all items of instrumentation shall be available and valid. For test, replacement and test antennas, the data shall include the isotropic radiation gain (or antenna factor) for the test frequency. In addition, the VSWR of the replacement and test antennas shall be known.

Calibration data on all cables and attenuators shall include attenuation and VSWR over the entire frequency range of the tests. All attenuation and VSWR data shall be recorded in the result log for the specific test.

When coefficients/correction tables are required, they should be available immediately. For all items of test equipment, the maximum measurement uncertainties they present shall be known together with the distribution of the measurement uncertainty.

At the beginning of the measurement, it is advisable to test the system on items of equipment used on the measuring area.

B.3.3. Standard test method

Two methods - calibration and replacement - for determining the radiated power of radio equipment are described in D.1 and D.2 of Appendix D, respectively.

The standard calibration method is also described in Appendix E.

B.4. Inspection of equipment connected to the host

For radar equipment that needs to be connected or integrated with a host to provide radar equipment functionality, a variety of replacement test methods shall be permitted.

When there is more than one such combination, the measurement shall not be repeated for the combination of radar equipment and many essentially similar hosts.

When there is more than one such combination and the combinations are not identical, each combination shall be tested for all requirements in this regulation and all different individual combinations shall be tested for radiated spurious emissions only (see 3.4).

NOTE: For more relevant information on the above, see ETSI TR 102 070-2.

Appendix C
(Normative)
Test areas and general arrangements for measurements involving the use of radiated fields
 

C.1. Introduction

This section introduces the test area that can be used for radiation measurements. The test area is often referred to as the free-field test area. Both absolute and relative measurements can be taken in these areas. The test chamber shall be pre-verified at the place where absolute measurements are taken. The detailed test procedure is described in ETSI TS 102 321.

C.2. Anechoic chamber

An anechoic chamber is a test site commonly used for radiation testing in accordance with this regulation with frequencies above 1 GHz. However, the ground plane anechoic chamber as described in C.2 may be used with frequencies above 1 GHz provided that suitable anechoic material is placed on the test chamber floor to suppress any reflected signals. An anechoic chamber is an enclosed and normally shielded test chamberin which the interior of walls, ceilings and floors is covered with a layer of radio-absorbing material, which is usually a pyramidal urethane foam. Typically, the chamber consists of an antenna support at one end and a turntable at the other. A typical anechoic chamber is depicted in Figure C.1

Figure C.1 - Typical anechoic chamber

The shielding of the test chamber combined with the use of radio-absorbing material creates a controllable environment during the test. This type of test chamber tries to best simulate conditions in free space. The shielding creates a test space that reduces interference from surrounding signals and other external effects, while the radio-absorbing material minimizes unwanted reflections from walls, floors and ceilings, which can affect measurements.

In fact, it can be easily shielded to eliminate high-level ambient noise (80 dB to 140 dB). Usually, it makes the ambient noise effect negligible.

A turntable is capable of rotating around 360° in the horizontal plane and it is used to support the EUT at a suitable height (e.g. 1 m) above the ground plane. The test chamber shall be large enough to carry out measurements in the far field of the EUT. Further information on the far-field measurement requirements is given in B.3.2.4 of Appendix B.

In general, an anechoic chamber has many advantages over other test chambers. It is less affected by ambient noise, less reflected from walls, ceilings and floors and is not weather dependent. However, it also has some disadvantages such as limited measuring distance and limited use at low frequencies due to the size of the pyramidal absorbing materials. To improve performance at low frequencies, a combination of ferrite brick structure and urethane foam absorber is often used.

All emission measurements can be performed in an anechoic chamber without any restrictions.

C.3. Conductive plane anechoic chamber

A conductive plane anechoic chamber shall be used to test the radiations covered by this regulation at frequencies below 1 GHz. An anechoic chamber is an enclosed and normally shielded test chamber in which the interior of walls and ceilings is covered with a layer of radio-absorbing material, which is usually a pyramidal urethane foam. The test chamber floor is made of bare metal (uncoated) and has the form of a flat surface.

Typically, the test chamber consists of an antenna mast at one end and a turntable at the other. A typical conductive plane anechoic chamberis shown in Figure C.2.

Figure C.2 - Typical conductive plane anechoic chamber

This type of test chamber attempts to simulate an outdoor test site whose main feature is to have an unlimitedly extended ideal platform.

The supply antenna mast has a variable height (from 1 m to 4 m) so that the test antenna can be optimally positioned between the signal and the antenna or between the EUT and the test antenna.

A turntable is capable of rotating around 360° in the horizontal plane and it is used to support the EUT at a specified height, usually 1.5 m above the ground plane. The test chamber shall be large enough to allow measurements in the far field of the EUT. Further information on the far-field measurement requirements is given in B.3.2.4 of Appendix B.

Firstly, the emission of the "peaking" electromagnetic field from the EUT is tested by raising and lowering the receiving antenna on the mast (to obtain maximum interference of the direct and reflected signals from the EUT), and then the turntable is rotated to reach the "peak" in the azimuth plane. At this height of the test antenna mast, the amplitude of the received signal shall be recorded.

Secondly, the EUT is replaced by a replacement antenna (placed at the EUT's phase center or volume center), which is connected to a signal generator. The signal again "peaks" and the signal generator output is tuned until the value reaches the value recorded in the first stage, and is measured again on the radio receiver.

Ground plane receiver sensitivity testing also involves "peaking" of the electromagnetic field by raising and lowering the receiving antenna on the mastto obtain maximum interference of the direct and reflected signals from the EUT, this time the center of the antenna used for measurement is placed at the EUT’s phase center or volume center during the test. A coefficient of variation is provided. The test antenna remains at the same height as in the second stage, where the test antenna is replaced by the EUT. The amplitude of the transmitted signal is reduced to determine the field strength level with a specific response obtained from the EUT.

C.4. Extreme test conditions

C.4.1. Transparent temperature test chamber with radio waves

A temperature chamber equipped with a transparent door or wall with radio waves can be used to make radiation measurements. The measurement procedure in this case shall be the same as that under normal conditions.

The EUT shallbe placed on a transparent support with radio waves. The distance between the test antenna and the EUT shall comply with the requirements in B.3.2.4 of Appendix B. Figure C.3 shows the measurement setup.

Figure C.3 - Setting up of extreme test conditions

C.4.2. Use of test fixture

C.4.2.1. General

A test fixture can be used to facilitate measurements under extreme conditions.

C.4.2.2. Characteristics

The fixture is a radio equipment for coupling the EUT's integrated antenna to the RF 50 Ω terminal at the frequency at which the measurements are required.

The test fixtures shall be fully described.

In addition, the test fixture shall provide:

1. Connection to an external power supply;
2. A method for providing input or output from the equipment. This may include coupling to or from the antenna. The test fixture may also provide suitable means of coupling, e.g. for data or video output.

The test fixtures are usually provided by the manufacturer.

The performance characteristics of the test fixture shall be approved by the test chamber and shall be in accordance with the following basic parameters:

1. The coupling loss shall not be more than 30 dB;
2. Appropriate bandwidth characteristics;
3. The variation of the coupling loss over the frequency range used for the measurement shall not exceed 2 dB;
4. Circuits associated with RF coupling contain non-active or non-linear devices;
5. VSWR at the 50 Ω terminal shall not be more than 1.5 over the frequency range of the measurements;
6. The coupling loss shall be independent of the position of the test fixture and not affected by the proximity of surrounding objects or people. The coupling loss shall be regenerated when the equipment is removed and replaced. Normally, the test fixture is in a fixed position and provides a fixed position for the EUT;
7. The coupling loss remains constant as the environmental conditions change.

The coupling loss of the test fixture which can have a maximum disturbance level from the test instrument is +10 dB. If the loss is too high, a linear LNA can be used outside of the test fixture.

Figure C.4 - Test fixture

The field probe (or small antenna) should be properly terminated.

The characteristics and validation shall be stated in the test results.

C.4.2.3. Validation of test fixture in temperature chamber

The test fixture is introduced into the temperature chamber (needed only if the test fixture measurements are made under extreme temperature conditions).

Step 1

A transmitting antenna connected to a signal generator shall be located from the test fixture at a far-field distance of not less than one λ at that frequency. The test fixture consists of a mechanical support for the EUT, an antenna or field probe and a 50 Ω attenuator to terminate the field probe. The test fixture shall be connected to the spectrum analyzer via a 50 Ωterminal. A signal generator shall be set to the rated frequency of the EUT (see Figure C.5). The output power of the unmodulated signal from the signal generator shall be set to a value that is high enough to be observable with a spectrum analyzer. This reference value shall be recorded in the test results. The signal generator is then set to the upper and lower band limits of the EUT's assigned frequency range. The measured values ​​shall not deviate more than 1 dB from the value at rated frequency.

Figure C.5 - Validation of test fixture without EUT

Step 2

During validation and testing, the EUT shall be attached to the test fixture in the off mode, see Figure C.6. The measurements in Step 1 shall be repeated, this time with the EUT in place. The measured values are compared with those in Step 1 and should not vary by more than 2 dB. This is so that the EUT does not cause a significant loss of radiated power.

Figure C.6 - Validation of test fixture with EUT in place

C.4.2.4. Using the test fixture for testing in the temperature chamber

Here, the signal generator and transmitting antenna are removed. The EUT is supplied with DC power via an external power supply (see figure C.7). In the case of EUToperated by battery, powered by a transient power supply as well as a transient control signal line, a coupling filter shall be added directly at the EUT to avoid parasites, electromagnetic radiation.

At the 50 Ω port of the test fixture, a measuring receiver is connected to record the parameters of interest.

Figure C.7 - Measurement of EUT taken in a temperature chamber

C.5. Test antenna

C.5.1. General

A test antenna is always used in radiation test methods. In emission measurements (i.e. effective radiated power, spurious emissions) the test antenna is used to detect the field from the EUT in one stage of measurement and from the replacement antenna in the other. When the test area is used to measure the receiver characteristics (i.e. sensitivity and different immunity parameters) the antenna is used as the radio transmitter.

The test antenna shall be mounted on a support capable of allowing the antenna to be used in either horizontal or vertical polarization, ground plane locations (i.e.ground plane anechoic chambers) should allow the addition of its height from the center of the ground to be varied within the specified range (usually 1 m to 4 m).

In the frequency range 30 MHz to 1,000 MHz, a dipole antenna (manufactured according to ANSI C63.5) is generally recommended. For frequencies 80 MHz and above, the dipole surfaces shall have a radiant surface length to resonate at the test frequency. For frequencies below 80 MHz, it is recommended to shorten the radiant surface length. However, for spurious emission measurements, a combination of symmetric antennas and periodic dipole array antennas (often referred to as "logicic") can be used to cover the entire frequency range 30 MHz to 1,000 MHz.Above1,000 MHz, loudspeaker waveguides are recommended, gain, and log periodic antennas can be used.

NOTE: The gain of a loudspeaker antenna is often described in relation to an isotropic radiator.

C.5.2. Replacement antenna

The replacement antenna is used to replace the EUT for the transmission parameters (i.e. frequency error, effective radiated power, spurious emissions and adjacent channel power) being measured. For measurements in the frequency range 30 MHz to 1,000 MHz, thereplacement antenna shall be a dipole one (manufactured according to ANSI C63.5). For frequencies 80 MHz and above, the dipole surfaces shall have a radiant surface length to resonate at the test frequency. For frequencies below 80 MHz, it is recommended to shorten the radiant surface length. For measurements above 1,000 MHz, a standard gain loudspeaker waveguide is recommended.

C.5.3 Measurement antenna

The measurement antenna is used in the tests on the EUT for the reception parameters (i.e. sensitivity and different immunity measurements) being measured. The purpose is to measure the electric field strength in the vicinity of the EUT.

For measurements in the frequency range 30 MHz to 1,000 MHz, the measurement antenna shall be a dipole one (manufacturedaccording to ANSI C63.5). For frequencies 80 MHz and above, the dipole surfaces shall have a radiant surface length to resonate at the test frequency. For frequencies below 80 MHz, it is recommended to shorten the radiant surface length. For measurements above 1,000 MHz, a standard gain loudspeaker waveguide is recommended. The center of this antenna should coincide with the phase or volume center (as specified in the test method) of the EUT.

Appendix D
(Normative)
Standard test method
 

D.1. Radiation test setup calibrated using Rx path calculation

The measuring receiver, test antenna and all associated equipment (e.g. cables, filters, amplifiers, etc.) shall be calibrated to known standards at all frequencies at which equipment measurements are made. A suggested calibration method is given in Appendix E.

If an anechoic chamber with a conductive plane is used, the floor shall be covered with absorbing material in the area of ​​ground reflection directly from the EUT to the test antenna.

The equipment shall be placed in an anechoic chamber (see Appendix C), allowing the spherical equipment to be assessed. The EUT shall be located closest to the normal operating direction.

The test antenna shall be oriented from the tip for vertical polarization and shall be selected to match the frequency of the transmitter.

The output of the test antenna shall be connected to a spectrum analyzer through any (full featured) equipment required to display a measurable signal (e.g. amplifier).

The EUT shall be switched on in unmodulated mode (if possible), and the spectrum analyzer shall be tuned to the frequency of the transmitter under test.

The test antenna shall be raised and lowered within the specified range of heights until a maximum signal level appears on the spectrum analyzer. Another way is to tilt the EUT within a suitable range.

The EUT shall then be rotated 360° in the horizontal plane, until a maximum signal level appears on the spectrum analyzer. Another way is to rotate the test antenna around the EUT.

The test antenna shall be raised and lowered again within the specified range of heights until a maximum signal level appears on the spectrum analyzer. Another way is to tilt the EUT within a suitable range.

The measurement shall be repeated with the test antenna oriented for horizontal polarization.

The maximum signal level detected by the spectrum analyzer shall be recorded and converted to radiated power by applying predefined calibration factors to the equipment configuration used.

D.2. Radiation test setup calibrated using replacement method

On the test area specified in Appendix C, the equipment shall be placed at the specified height on the support as specified in Appendix C and in the position closest to normal use as declared by the manufacturer.

The test antenna shall be initially oriented for vertical polarization and shall be selected to correspond to the frequency of the transmitter.

The output of the test antenna shall be connected to a spectrum analyzer.

The EUT shall be switched on in unmodulated mode (if possible), and the spectrum analyzer shall be tuned to the frequency of the transmitter under test.

The test antenna shall be raised and lowered within the specified range of heights until a maximum signal level appears on the spectrum analyzer. Another way is to tilt the EUT within a suitable range.

The EUT shall then be rotated 360° in the horizontal plane, until a maximum signal level appears on the spectrum analyzer. Another way is to rotate the test antenna around the EUT.

The test antenna shall be raised and lowered again within the specified range of heights until the maximum signal level appears to the spectrum analyzer. Another way is to tilt the EUT within a suitable range.

The maximum signal level received by the spectrum analyzer shall be recorded.

The EUT shall be replaced with a replacement antenna as defined in Appendix C.

The replacement antenna shall be oriented for longitudinal polarization and the length of the replacement antenna shall be adjusted to correspond to the frequency of the transmitter.

The replacement antenna shall be connected to a calibrated signal generator.

If necessary, the input attenuation system of the spectrum analyzer shall be tuned to increase the sensitivity of the spectrum analyzer.

The test antenna shall be raised and lowered within the specified range of heights to ensure maximum signal reception. Another way is to tilt the replacement antenna through a suitable range. When a test area as specified in C.2 is used, the height of the antenna shall not be changed.

The input signal to the replacement antenna shall be tuned to a level that produces a level detected by the spectrum analyzer, equal to the transmitter radiated power level that has been measured, tunedto change the input attenuation setting of the spectrum analyzer.

The input value of the replacement antenna shall be recorded as the power level, correction factor for any variation in the input attenuation system of the spectrum analyzer.

The measurement shall be repeated with the test antenna and the replacement antenna oriented for horizontal polarization.

The radiated power of the radio equipment measured is the greater of the two levels received at the input of the replacement antenna and the correction factor for the gain of the replacement antenna.

Appendix E
(Normative)
Rx path calculation
 

This appendix describes in detail the calibration procedure to facilitate measurements as described in D.1 of Appendix D.

The calibration sets up measurements that establish the relationship between the received output and the transmit power (sampled at the location of the transmitting antenna) from the EUT at the test site. This can be achieved (at higher frequencies)using a calibrated antenna with a given gain, supplied from an external signal source, instead of the EUT to determine variations in received power with respect to frequency. The calibrations are set up as described in Figure E.1.

Figure E.1 - Calibration setup configuration

For higher frequencies, typically above 40 GHz, a converter/mixer can be used between the receiving antenna and the measuring receiver, as shown in Figure E.2.

Figure E.2 - Calibration setup configuration including mixer

Calibration of the setting for the measurement shall be performed by the manufacturer or the testing laboratory. The results shall be approved by the test chamber.

It is the responsibility of the person who performs the test to obtain correct results of the measurement. Here is an example of a proven correct calibration method:

a) Calibrate all instruments using the usual calibration procedures.

b) Remove the EUT from the test fixture and replace the EUT with a calibrated antenna. Carefully orient the calibrated antenna in the EUT with respect to the test arrangement antenna. The reference plane of the calibrated antenna shall coincide with the EUT reference plane. The distance between the calibrated antenna and the test arrangement antenna shall be based on the results according to B.3.2.4 of Appendix B.

c) Connect the signal generator to the calibrated antenna.

d) Connect a 10 dB attenuator to the test arrangement antenna to improve VSWR. If the SNR of the test antenna is low, the attenuator can be omitted.

e) Connect the power meter to the test arrangement antenna, including a 10 dB attenuator, if necessary, set the signal generator to a frequency and power level similar to the expected value of EUT output.

f) The gain from both the calibrated and test arrangement antennas, the loss from the attenuator and all cables in use, the LNA gain and the converter/mixer gain, shall be taken into account, if necessary.

g) Record the absolute power meter reading.

h) Replace the power meter with a spectrum analyzer.

i) Tune the frequency and power level of the signal generator to the same values ​​as the EUT output. Apply this signal to the calibrated antenna.

j) Take into account the gain from both the calibrated and test arrangement antennas, the loss from the attenuator and all cables in use, the LNA gain and the converter gain/ mixer, if necessary. Instead of an external attenuator, a spectrum analyzer's built-in attenuator can be used.

k) Set the spectrum analyzer in RMS mode with RBW and VBW at least equal to the signal generator’s output signal bandwidth with the appropriate spectrum analyzer sweep rate. Record the absolute reading of the spectrum analyzer input signal.

l) The absolute power read from the power meter and spectrum analyzer shall not differ by more than the specified uncertainty of the measuring instruments used.

m) Calculate the total loss from the EUT reference plane to the spectrum analyzer as follows:

P_reading       =        absolute power level (e.g. dBm) recorded from the power meter/spectrum analyzer.

G_Tx = antenna gain (in dB) of the calibrated antenna in the EUT

G_Rx = antenna gain (in dB) of the test arrangement antenna.

G_ATT =        10 dB attenuator (0 dB, if no attenuator is used).

G_cable =        the total loss (in dB) of all cables used in the test.

G_LNA =        low noise amplifier gain (0 dB, if no LNA is used).

G_Mix  =        mixer gain (0 dB, if no mixer is used)

NOTE: Typically, the mixer has a conversion loss but may include an LNA to compensate for some of the output gain.

G_fs_loss       =        free space loss (in dB) between the calibrated antenna (Tx) in the EUT and the test arrangement antenna (Rx).

C_ATT =        calculated loss (in dB) of all losses referenced to the EUT position.

C_ATT =        G_fs_loss - G_Rx + G_cable2 – G_LNA + G_cable1 + G_ATT.

P_e.i.r.p.         =        absolute power level (e.g. dBm) of the EUT (e.i.r.p.).

P_e.i.r.p.         =        P_reading - C_ATT.

Calibration shall be performed at a minimum of three frequencies within the operating frequency range.

Or if a mixer is used:

​​G_cable1 and G_cable2 values are negative. Depending on the mixer selected, it may be the same as G_Mix.

A test area as described in Appendix C, which meets the requirements of the specified frequency range and the specified lowest undisturbed emission levels of this measurement, shall be used.

Appendix F
(Normative)
Measuring receiver
 

F.1. General comments

A measuring receiver includes power meters, spectrum analyzers, signal analyzers and comparators. If a suitable measuring receiver is not available to handle the EUT transmission frequency directly, an external down-converter is used to shift the EUT transmission frequency range to a frequency range suitable for the available receiver (see Figure F.1). The preamplifier shall be selected so that the amplitude of the measured signal is better than the sensitivity of the measuring receiver.

Figure F.1 - Using a down-converter in front of the measuring receiver

To determine e.i.r.p values, the reading from the measuring receiver (which may include a down-converter) shall be calibrated to include both gain and loss, e.g. antenna gain, free space loss, etc.and the quantity required to be calibrated using the replacement method (see also Appendix D).

F.2. Power meter

For power level measurement, a power meter is a suitable measuring receiver. Various power measuring sensors are available:

a) True peak power sensor.

b) Mean power sensor (true RMS). It may be:

- a thermistor-based power meter; or

- a diode-based power meter with a sufficiently high averaging time. It should be noted that the correct power correction factor is chosen for the input frequencies

F.3. Spectrum analyzer

To measure simple quantities such as occupied bandwidth, a spectrum analyzer is a suitable measuring receiver.

This equipment is characterized by the following parameters:

• Start frequency;

• Stop frequency;

• Resolution bandwidth;

• Video bandwidth;

• Detector mode (e.g. peak, RMS, etc.);

NOTE: RMS measurements can be performed directly using a spectrum analyzer incorporating an RMS detector. Alternatively, the true RMS level can be measured with a spectrum analyzer that does not incorporate an RMS detector (see ITU-R SM.1754 recommendation for details).

• Display mode (e.g. Max-hold, etc.);

• Averaging time;

• Sweep time.

• Marker handling, for example:

• 99% OBW function: the power envelope of the occupied bandwidth will contain 99% of the emission,
• Channel power function, they integrate RMS power density over a certain frequency range.

The resolution bandwidth and resolution filter response of the spectrum analyzer shall be in accordance with CISPR16.

In order to obtain the required sensitivity, a narrower measurement bandwidth may be required, which in such cases will have to be stated in the test results. The resolution bandwidth of the spectrum analyzer is given in Table F.1

Table F.1 - Measuring receiver characteristics

F.4. Signal analyzer

To measure complex parameters such as frequency versus time, a signal analyzer is a suitable measuring receiver. Signal analyzers are FFT-based devices. The results of the measurements using the signal analyzer are: Spectrum chart, showing time on the X axis, frequency on the y axis and amplitude as color coded dots (see example in Figure F.2). Using a marker, it is also possible to read quantitative power levels for a given time and frequency position.

Marker+:2.74 ms, 24127.04 MHz, -48.3dBm

Figure F.2 - Example of measurement results using a spectrum chart

This instrument is characterized by the following parameters:

• Total measurement time;
• Time resolution;
• Frequency range;
• Frequency resolution;
• Minimum power level;
• Maximum power level;
• Power level resolution.

That can be shifted to the following settings for analog-to-digital and FFTconversion:

• Sampling rate = 2 x the maximum frequency occurring at the signal analyzer input

(= down-converter output if a converter is used)

• FFT size = Sampling rate/frequency resolution;
• Time difference between consecutive FFTs = Time resolution;
• Number of FFTs = Total measurement time/time resolution.

F.5. Oscilloscope

To measure the dependence in the time domain, an oscilloscope is a suitable measuring receiver.

For example, for power duty cycle measurement, the measurement method using an oscilloscope is described in ETSI TR 103 366.

To ensure reception of the desired signals, a preamplifier and/or envelope detector may be required in front of the oscilloscope input.

Appendix G
(Normative)
HS code of radar equipment operating in the frequency range 76 GHz to 77 GHz for ground based vehicle
 

Bibliography of references

[1] ETSI EN 303 396 V1.1.1 (2016-12) - Short Range Devices; Measurement Techniques for Automotiveand Surveillance Radar Equipment;

[2] ETSI EN 301 091-1 V2.1.1 (2017-01) - Short Range Devices; Transport and Traffic Telematics (TTT); Radar equipment operating in the 76 GHz to 77 GHz range; Harmonised standard covering the essential requirements of article 3.2 of Directive 2014/53/EU; Part 1: Ground based vehicular radar.

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