GB/T 4958.1-1985 Measurement methods for equipment used in terrestrial radio-relay systems Part 1: Measurements common to subsystems and simulation systems Section 1 General
Some standard content:
National Standard of the People's Republic of China
GB/T 4958.1—1985
idtIEC487-1A:1980
Methods of measurement for equipment used in terrestrial radio-relay systems Part 1: Measurements common to sub-systems and simulated systems Section One-General
Published on February 16, 1985
National Bureau of Standards
Implementation on August 1, 1985
National Standard of the People's Republic of China
Methods of measurement for equipment used in terrestrial radio-relay systems Part 1: Measurements common to sub-systems and simulated systems Section One-General and simulated systemsSectionOne-General
UDC621.396
GB/T4958.1—1985
IEC487—1(1974)
487—1A(1980)
The standard for measurement methods for equipment used in ground radio relay systems includes three parts. Part 1: Common measurements for subsystems and simulated systems. Part 2: Measurements for subsystems. Part 3: Measurements for simulated systems. Each part includes several substandards. "General" is a substandard in the first part, which is applicable to all parts. The general provisions are equivalent to the international standard IEC487-1 "Measurement methods for equipment used in terrestrial radio-relay systems Part 1: Measurements common to subsystems and simulation systems Section 1 General provisions" (now IEC487-1 (1974] Section 1 and its supplement: 487-1A [1980]). 1 Purpose
The purpose of formulating the standard for measurement methods for equipment used in terrestrial radio-relay systems is to standardize the measurement conditions and measurement methods for determining the performance of terrestrial radio-relay systems and equipment used in the system, and to enable the results measured by different observers to be compared. It includes Details of the measurement methods selected to assess the main performance of terrestrial radio-relay systems and the equipment used therein. These measurement methods are neither mandatory nor restrictive and the selection of measurements can be made according to each specific situation. If necessary, additional measurements may be added, but the additional measurements shall comply with the methods specified in other national standards. In this standard, acceptable limits for various performance parameters are not specified, as these limits should be given in the detailed equipment specifications.
The measurement methods described in this standard are intended for "type" and "acceptance" tests and may also be used for factory tests. 2 Scope of application
The standard test conditions and performance measurement methods specified in Part 1 of this standard are applicable to subsystems of terrestrial line-of-sight radio-relay systems and FM simulation systems. The tests described are limited to analog transmission systems. These measurement methods are general methods applicable to systems of both large and small capacity. However, in systems with a capacity of 60 channels or less, some performance does not need to be specified and measured. The measurements to be made shall be agreed upon by the relevant departments. 3 Terms and definitions
In this part and other parts of this standard, the parameters to be measured are described before the measurement methods are described. Definitions. In order to indicate the relevance of the definitions, they may be described in the relevant clauses or listed as independent clauses. The definitions in this standard are consistent with the definitions specified in the current relevant national standards as much as possible. Some definitions differ from the definitions in the relevant national standards. The purpose is to better understand this standard. These differences are necessary. 3.1 Detailed equipment specifications Equipment specification is a specially prepared or provided document that describes the performance and parameters of the equipment under specified conditions of normal use, as well as the conditions under which failures may occur.
Note: In order to assess whether the equipment complies with the general principles and test methods to be followed in the safety regulations under normal use conditions and specified failure conditions, the relevant provisions of "Safety Requirements for Radio Transmitting Equipment" should be referred to. 3.2 Terrestrial Radio-Relay System
Terrestrial Radio-Relay System For the purpose of the standard, the equipment that constitutes a terrestrial radio-relay system is shown in Figure 1. 3.3 Model
A model refers to products with similar design features, similar manufacturing processes, and within the manufacturer's usual range of characteristics. Note: ① If the installed accessories have no significant effect on the test results, they can be ignored ② "Characteristics" include the following:
a) electrical ratings;
b) dimensions;
c) performance affected by the environment.
③ Each performance index and limit value shall be agreed upon by the buyer and the manufacturer. 3.4 Type test
typetest
Type test is a complete series of tests on a number of samples that can represent a certain model. The tests are used to determine which manufacturer can produce products that meet the specifications.
3.5 Type approval
typeapproval
Type approval is a decision made by the appropriate competent authority, such as a government agency, the purchaser itself or its designated agent, recognizing that a manufacturer is capable of producing a sufficient number of products of that model that meet the requirements. 3.6 Acceptance tests
acceptancetests
Acceptance tests are tests carried out to determine whether the delivery is acceptable based on the agreement between the manufacturer and the purchaser. The agreement should include:
a number of samples;
b choice of test;
c tolerances and exceptions.
Note: If the respective test methods produce different results, the method preferred by the national standard should be adopted. 3.7 Factory tests Factory tests are tests performed by the manufacturer to confirm that their products meet the specifications. 4 Measurement conditions Care should be taken to exclude all conditions that may cause damage to the equipment. Unless otherwise specified, the various measurements shall be carried out under the standard conditions of power supply, temperature, air pressure, humidity and terminal load given below. After the equipment is finally adjusted to these conditions, the various adjustment devices shall remain unchanged during all measurements, except for those that must be adjusted before or during the measurement as specified. 5 Standard test conditions 5.1 Standard power supply conditions Measurements under standard power supply conditions are measurements made at the nominal voltage and nominal frequency specified in the detailed equipment specifications. The voltage shall be measured at the power supply terminals of the equipment under test. Unless otherwise specified, the power supply voltage and frequency shall not deviate from the nominal value by more than ± 2% during measurements on a subsystem or simulation system. Unless otherwise specified, standard power supply conditions include the supplementary conditions specified in Chapter 6. 5.2 Standard atmospheric conditions
Measurements under standard atmospheric conditions are usually carried out under the conditions specified in 5.2.1. If necessary, the measurement results should be corrected by calculation to the parameter values of the standard reference temperature of 20°C and the standard reference air pressure of 101.3 kPa specified in 5.2.2. If such correction is not possible, the measurement should be carried out according to one of the standard arbitration conditions specified in 5.2.3, and the set corresponding to room temperature of 20±1°C should be preferred.
Note: The standard atmospheric conditions specified in 5.2.1, 5.2.2, and 5.2.3 are consistent with the conditions specified in GB2421-1981 "General Rules for Basic Environmental Testing Procedures for Electrical and Electronic Products".
5.2.1 Standard test conditions
The measurement results are either independent of temperature and air pressure, or can be corrected by calculation to 5.2.Under the standard reference temperature and pressure specified in Article 2, these measurements and mechanical tests can usually be carried out under the combination of ambient temperature, humidity and pressure within the following limit values: temperature:
relative humidity:
pressure:
+15~+35℃;
45%~75%,
86~106kPa.
If the measured parameters change with temperature, humidity and pressure, and their changing rules are unknown, the standard arbitration conditions of Article 5.2.3 should be adopted.
5.2.2 Standard reference conditions
If the measured parameters change with temperature and (or) pressure, and their changing rules are known, the parameter values should be measured under the conditions specified in Article 5.2.1. If necessary, the parameter values can be calculated and corrected to the following standard reference atmospheric conditions: temperature: +20℃;
pressure: 101.3kPa.
Note: Relative humidity is not required because it is usually not possible to correct for it by calculation. 5.2.3 Standard arbitration conditions
If the measured parameter changes with temperature, air pressure and humidity, and the law of change is unknown, the supply and demand parties shall agree to select one of the following combined conditions for measurement:
20±1℃
23±1℃
25±1℃
27±1℃
Relative humidity
63%~67%
48%~52%
48%~52%
63%~67%
86~106kPa
86~106kPa
86106kPa
If the buyer and the manufacturer agree, the measurement may not be carried out according to the temperatures listed in the above table. In this case, an agreement shall also be reached on the appropriate limit values of various parameters. The actual temperature, relative humidity and pressure values during the measurement period shall be given in the measurement results. Note: For large equipment or in laboratories where the above temperature, relative humidity and (or) pressure limits are difficult to maintain, the tolerances may be relaxed with the agreement of both parties, but the actual values shall be given in the test results. 3
6 Supplementary conditions for power supply
GB/T4958.1—1985
The power supply used for equipment testing shall be sufficiently stable in addition to complying with the relevant provisions of the equipment specification. Changes in power supply characteristics shall not cause significant changes in the performance of the equipment under test. Generally speaking, if the power supply complies with the provisions of 6.1 and 6.2, the above conditions will also be met. 6.1 AC power supply conditions
6.1.1 Waveform and source impedance
If not otherwise specified, the AC power supply connected to the AC power supply terminals of the equipment shall be a substantially sinusoidal AC voltage source, and its source impedance shall be low enough to make the effect on the operation of the equipment negligible. If the maximum deviation of any part of the curve from the instantaneous value of the fundamental does not exceed 5% of the amplitude of the fundamental, the voltage waveform can be considered to be roughly sinusoidal (i.e. |a-/0.05c), see Figure 2. 6.1.2 Symmetry of multiphase systems
The voltage of the multiphase power supply should be symmetrical.
When the equipment is in operation, the voltage of the multiphase system can be considered to be symmetrical if the reverse phase sequence and zero phase sequence components do not exceed 1% of the positive phase sequence component with respect to the fundamental (see Figure 3). If a multiphase system is not completely symmetrical but is still within this limit, the arithmetic mean of all phase-to-phase voltages should be used as the power supply voltage.
6.2 DC power supply conditions
Equipment used in ground radio relay systems can be powered by a test DC power supply. This DC power supply can be: a. A battery with or without floating charge;
b. A rectifier powered by an AC power supply (see Section 5.1). The power source used to obtain the dc test voltage shall not power other equipment during the test. 6.2.1 Source Impedance and Polarity
Unless otherwise specified, the source impedance of the dc power source shall be low enough so that its effect on the device under test is negligible. One specified electrode of the dc power source shall be grounded.
6.2.2 Noise Superimposed on the DC Test Voltage 6.2.2.1 General Considerations
Noise generated in the dc power source and superimposed on the dc test voltage may affect the performance of the device under test. When the device under test is connected to the dc power source, the noise that appears on the dc test voltage may be caused by the dc power source itself or introduced by the device under test. When specifying the dc power supply conditions, only noise related to the dc power supply is considered. Noise that appears on the dc power supply may be relatively continuous or transient and accidental. Both types of noise may also appear simultaneously. Non-repetitive transient noise (for example, transient noise caused by fuse blowing or circuit breaker operation) shall be ignored if it does not cause damage to the device under test.
If other equipment is connected to the DC power supply at the same time as the equipment under test, they will introduce noise to the DC test voltage. Therefore, it is desirable to avoid supplying DC power to two or more equipment at the same time. If necessary, an equivalent passive load can be used instead of the equipment under test, and the noise voltage across the load can be measured to verify the noise voltage generated in the DC power supply and superimposed on the DC test voltage. Only when there is a disagreement among the parties concerned, the following method should be used for measurement. In this case, the maximum noise value should be agreed upon by the parties concerned.
6.2.2.2 Frequency-selective measurement of superimposed noise
For convenience, the frequency spectrum of the noise can be measured directly using a frequency-selective level meter or a radio interference measurement device. One electrode of the DC power supply should be grounded, and the other electrode should be connected to the input of the frequency-selective level meter or the radio interference measurement device through a capacitor. At the lowest frequency measured, the series impedance of the capacitor should be less than one-tenth of the input impedance of the test instrument. The voltage rating of the capacitor should be the power supply voltage plus an appropriate safety factor. GB/T4958.1—1985
The connecting line from the test instrument to the DC power supply should be as short as possible. It is best to use a coaxial cable. Care must be taken to prevent the DC power supply from being short-circuited. The frequency range of the measurement should include all baseband frequencies of the device under test. The bandwidth of the frequency-selective level meter or radio interference measuring device should be adapted to the noise spectrum being measured. Since spectral lines separated by 50 Hz or 60 Hz may appear, a bandwidth of about 10 Hz is appropriate for frequencies between 0 and 10 kHz. For frequencies between 10 kHz and 150 kHz, a bandwidth of 200 Hz is more appropriate. For frequencies above 150 kHz, a bandwidth of 500 Hz to 6 kHz can be used. Note: For details of the radio interference measuring device and the measurement method, refer to the relevant national standards. 6.2.2.3 Broadband measurement of superimposed noise
Broadband measurements require the use of a broadband oscilloscope, the bandwidth of which should be at least twice the baseband bandwidth. The peak-to-peak value of the superimposed noise voltage is expressed as a percentage of the nominal value of the DC voltage (for example: 2%). 7 Measurements under non-standard test conditions
If necessary, the performance of the equipment can also be determined after or during a period of time when the equipment is subjected to conditions different from the standard test conditions specified in Clause 5.
In this case, the acceptable performance degradation and the conditions for testing should be given in the detailed equipment specification (the conditions in the following clauses should be given priority).
7.1 Initial measurements under standard test conditions The characteristics of the equipment should first be evaluated under standard test conditions (see Clause 5). Since these characteristics may vary with temperature and humidity and their variation patterns are generally unknown, measurements should be made under a set of standard arbitration conditions specified in Clause 5.2.3, preferably the set corresponding to an ambient temperature of 20 ± 1 °C. 7.2 Changes in power supply voltage within the specified range 7.2.1 Definition
The power supply voltage range refers to the voltage range within which the equipment can operate with the specified performance. 7.2.2 Test conditions
The equipment under test should operate under standard atmospheric conditions (see 5.2) and standard power supply conditions (see 5.1), but the voltage should be adjusted to the maximum and minimum values specified in the detailed equipment specification during measurement, and the measurement should be carried out after the equipment reaches thermal equilibrium. 7.3 Changes in ambient temperature within the specified temperature range 7.3.1 Definition
The term "temperature range" refers to the range of ambient temperatures within which the equipment can operate normally with the specified performance. 7.3.2 Test conditions
The equipment should operate under standard power supply conditions, and the temperature should be raised or lowered to the maximum and minimum temperature values specified in the detailed equipment specification. The test conditions shall comply with GB2423.2-1981 "Basic Environmental Test Procedure for Electrical and Electronic Products Test B: High Temperature Test Method" and GB2423.1-1981 "Basic Environmental Test Procedure for Electrical and Electronic Products Test A: Low Temperature Test Method". 7.4 Humidity
If the test is required to be carried out under the specified humidity conditions, it shall be carried out according to GB2423.3-1981 "Basic Environmental Test Procedure for Electric and Electronic Products Test Ca: Steady Humidity Test Method" is used for testing. When the required humidity and temperature are periodic changes, reference should be made to GB2423.4-1981 "Basic Environmental Test Procedure for Electric and Electronic Products Test Db: Alternating Humidity Test Method". Adoption instructions:
IEC original text is: "IEC Publication 68-2-4, Test D: Accelerated Humidity Test". However, the IEC 50th Technical Committee Paris Meeting (1979) decided to withdraw "Test D" by January 1, 1983. IEC recommends that all newly designed products use "Test Db" instead of "EC Publication 68-2-4 "Test D: Accelerated Humidity Test" (see IEC68-2-30C1980) page 7). GB2423.4-1981 is the standard corresponding to IEC68-2-30. 5
7. 5 Other environmental conditions
GB/T4958.11985
After the supplier and the buyer agree, other environmental conditions tests different from those specified in the above clauses, such as vibration, impact, dust and (or) sand and dust tests, are carried out to determine the performance of the equipment. The equipment shall be subjected to the relevant test conditions in the GB2423-1981 series of standards "Basic Environmental Test Procedures for Electrical and Electronic Products". During or after the test, performance measurements shall be made. The tests to be conducted shall be agreed upon by both parties. The conditions and methods shall be selected from the GB2423-1981 series of standards. r
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Figure 1 Typical combined connection of wireless equipment of ground radio relay system6
GB/T4958.1—1985
Voltage waveform of AC power supply
is the instantaneous value of voltage $6-is the instantaneous value of fundamental wave c-is the amplitude of fundamental wave s
Figure 3 Unbalance of three-phase system
(a)—asymmetric system, (b)—positive phase sequence system; (c)—reverse phase sequence system, (d)—zero sequence system Note: Any asymmetric three-phase system can be considered as the superposition of three symmetrical systems, namely the positive phase sequence system, the reverse phase sequence system and the zero sequence (in-phase) system. In these symmetrical systems There is a clear relationship between the components and the original asymmetric system amplitude and phase imbalance. Taking the case that the reverse phase sequence component and the zero phase sequence component are both α% of the positive phase sequence component, and the maximum component of the asymmetric system exceeds the minimum component by less than 3%, the phase imbalance △@ is less than 1.72a degrees.
When a is less than 5%, these approximate values are correct. 7
A.1 Subsystem①
sub-system
GB/T4958.1—1985
Appendix A
Supplementary terms and definitions
(Supplement)
Subsystem is defined as a combination of circuits and devices that can perform a specified function (such as modulation, RF branching or multi-channel switching) and have specified electrical, mechanical and environmental characteristics. A.2 Simulated system
simulated system
A simulated system consists of two or more subsystems. It partially represents an actual working radio relay system. Therefore, by measuring the results obtained from the simulation system, a meaningful evaluation of the performance of an actual system can be made. A.3 Typical simulated system
typical simulated system
A typical simulated system can fully represent an actual system and is suitable for the finalization test of the system. This simulation system consists of a number of subsystems. These subsystems have similar design features, similar manufacturing processes, and are within the manufacturer's usual range of characteristics. Additional notes:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China and is under the jurisdiction of the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications and the 54th Institute of the Ministry of Electronics Industry of the People's Republic of China. The main drafter of this standard is Liu Yunhai.
The main body of this standard is consistent with the international standard IEC487-1 (1974) Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General (IEC Recommendation, publication 487-1, first edition 1974, Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General) and the first supplement to IEC487-1 (1974) (IEC Standard, publication 487-1A 1980) in terms of technical content. Since the first part of this standard involves some terms and definitions listed in the second and third parts, and these terms have no unified names in my country. In order to standardize them, they are temporarily listed in this standard in the form of an appendix. After the second and third parts are formulated as national standards, they can be withdrawn when this standard is revised next time.
①See IEC487-2-1 (1981) \4". ②See IEC487-3 (1975) "102.1" and \102.2". In order to avoid confusion with "analog transmission system", the Chinese name of "Simulated system" is defined as "simulation system" instead of "simulation system". 872a degrees.
These approximate values are correct when a is less than 5%. 7
A.1 Subsystem①
sub-system
GB/T4958.1—1985www.bzxz.net
Appendix A
Supplementary terms and definitions
(Supplement)
A subsystem is defined as a combination of circuits and devices that can perform a specified function (such as modulation, radio frequency branching or multi-channel switching) and have specified electrical, mechanical and environmental characteristics. A.2 Simulated system
simulated system
A simulated system consists of two or more subsystems. It partially represents an actual working radio relay system. Therefore, by measuring the results obtained from the simulated system, a meaningful evaluation of the performance of an actual system can be made. A.3 Typical simulated system
typical simulated system
A typical simulated system can fully represent an actual system and is suitable for the system's type test. This simulation system consists of several subsystems. These subsystems have similar design features, similar manufacturing processes, and meet the usual characteristics of the manufacturer. Additional notes:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China and is under the jurisdiction of the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications and the 54th Institute of the Ministry of Electronics Industry of the People's Republic of China. The main drafter of this standard is Liu Yunhai.
The main body of this standard is consistent with the international standard IEC487-1 (1974) Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General (IEC Recommendation, publication 487-1, first edition 1974, Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General) and the first supplement to IEC487-1 (1974) (IEC Standard, publication 487-1A 1980) in terms of technical content. Since the first part of this standard involves some terms and definitions listed in the second and third parts, and these terms have no unified names in my country. In order to standardize them, they are temporarily listed in this standard in the form of an appendix. After the second and third parts are formulated as national standards, they can be withdrawn when this standard is revised next time.
①See IEC487-2-1 (1981) \4". ②See IEC487-3 (1975) "102.1" and \102.2". In order to avoid confusion with "analog transmission system", the Chinese name of "Simulated system" is defined as "simulation system" instead of "simulation system". 872a degrees.
These approximate values are correct when a is less than 5%. 7
A.1 Subsystem①
sub-system
GB/T4958.1—1985
Appendix A
Supplementary terms and definitions
(Supplement)
A subsystem is defined as a combination of circuits and devices that can perform a specified function (such as modulation, radio frequency branching or multi-channel switching) and have specified electrical, mechanical and environmental characteristics. A.2 Simulated system
simulated system
A simulated system consists of two or more subsystems. It partially represents an actual working radio relay system. Therefore, by measuring the results obtained from the simulated system, a meaningful evaluation of the performance of an actual system can be made. A.3 Typical simulated system
typical simulated system
A typical simulated system can fully represent an actual system and is suitable for the system's type test. This simulation system consists of several subsystems. These subsystems have similar design features, similar manufacturing processes, and meet the usual characteristics of the manufacturer. Additional notes:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China and is under the jurisdiction of the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Post and Telecommunications Industry Standardization Institute of the Ministry of Posts and Telecommunications and the 54th Institute of the Ministry of Electronics Industry of the People's Republic of China. The main drafter of this standard is Liu Yunhai.
The main body of this standard is consistent with the international standard IEC487-1 (1974) Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General (IEC Recommendation, publication 487-1, first edition 1974, Methods of measurement for equipment used in terrestrial radiorelay systems part 1: Measurements common to sub-systems and simulated radiorelay systems. Section One-General) and the first supplement to IEC487-1 (1974) (IEC Standard, publication 487-1A 1980) in terms of technical content. Since the first part of this standard involves some terms and definitions listed in the second and third parts, and these terms have no unified names in my country. In order to standardize them, they are temporarily listed in this standard in the form of an appendix. After the second and third parts are formulated as national standards, they can be withdrawn when this standard is revised next time.
①See IEC487-2-1 (1981) \4". ②See IEC487-3 (1975) "102.1" and \102.2". In order to avoid confusion with "analog transmission system", the Chinese name of "Simulated system" is defined as "simulation system" instead of "simulation system". 8
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