阅读说明：本技术 一种基于频谱仪的噪声系数快速测试方法及测试系统 (Noise coefficient rapid test method and test system based on frequency spectrograph ) 是由 甘欣辉 宋亮 姚连喜 万韬 郑前 周栋 彭景法 付元炳 于 2021-07-02 设计创作，主要内容包括：本发明公开了一种基于频谱仪的噪声系数快速测试方法及测试系统,测试方法采用频谱仪,基于冷态热态的方式对噪声源进行温度参数进行等效测试,直接对被测单元进行噪声测试及算法修正,最终获得噪声系数的测试结果。本发明支持接收机噪声系数测试为典型的变频模式下噪声系数测试和低噪放噪声系数测试为典型的非变频模式下噪声系数测试两种,在此基础上实现了非变频和变频模式下噪声系数的测试,从而大大提升了该测试方法的应用场合。(The invention discloses a fast test method and a test system for a noise coefficient based on a frequency spectrograph. The invention supports the noise coefficient test of the receiver as a noise coefficient test in a typical frequency conversion mode and a low-noise amplification noise coefficient test as a noise coefficient test in a typical non-frequency conversion mode, and realizes the noise coefficient test in the non-frequency conversion mode and the frequency conversion mode on the basis, thereby greatly improving the application occasion of the test method.)

1. A fast test method for noise coefficient based on a frequency spectrograph is characterized in that a frequency spectrograph module is adopted in the test method, equivalent test is carried out on temperature parameters of a noise source based on a cold-state and hot-state mode, noise test and algorithm correction are directly carried out on a unit to be tested, and finally a test result of the noise coefficient is obtained.

2. The fast test method for noise figure based on spectrometer as claimed in claim 1, wherein the test method comprises the following steps:

firstly, a frequency spectrograph is connected with a matched load or an open circuit, a test system is initialized, the noise power in each frequency point of the frequency spectrograph is calibrated, and the noise density is converted;

secondly, sequentially cascading a solid-state noise source to an input port of the unit to be tested, and an output port of the unit to be tested to a radio frequency input port of a frequency spectrograph module, then selecting a test mode as a non-frequency conversion mode or a frequency conversion mode according to the characteristics of the unit to be tested, and inputting related frequency points;

and step three, testing the noise value of the tested unit in the on and off states of the solid noise source, and converting the noise coefficient.

3. The method according to claim 2, wherein the first step is specifically:

by adopting the method for testing the noise power of the frequency spectrograph, under the condition that a radio frequency port of the frequency spectrograph is not connected with other things, the noise power of the frequency spectrograph is directly obtained, the noise power density of the frequency spectrograph is further obtained, the noise power density is compared and converted with the natural noise density at the current temperature, and the noise increment is converted to obtain the equivalent test noise temperature of the frequency spectrograph.

4. The method as claimed in claim 2, wherein the method comprises two test scenario modes: the device comprises a non-frequency conversion mode and a frequency conversion mode, wherein the non-frequency conversion mode and the frequency conversion mode are respectively used for realizing noise coefficient testing under frequency conversion scenes such as a receiver and the like and under non-frequency conversion scenes such as low noise amplification and the like.

5. The method as claimed in claim 4, wherein when the output frequency of the unit under test is not equal to the input frequency, the frequency conversion mode is selected, the solid-state noise source selects the test frequency ENR to input to the unit under test, the solid-state noise source is turned on and off, and the output of the spectrometer is sequentially detected.

6. The method as claimed in claim 4, wherein when the output frequency of the unit under test is equal to the input frequency, the non-variable frequency mode is selected, the input frequency ENR is selected by the solid-state noise source and input to the unit under test, and the solid-state noise source is turned on and off to sequentially detect the output of the spectrometer.

7. The method as claimed in claim 5 or 6, wherein the power test of the noise is modified in three ways, the first is averaging in the frequency domain, and the influence of noise fluctuation on the frequency is eliminated by summing and averaging the noise test results in a continuous frequency range; the second is averaging in the time domain, and the fluctuation variation of noise fluctuation in time is eliminated by averaging the noise test results at different moments at one frequency point; the third is multipoint sampling, which samples a plurality of discrete frequency points.

8. The method as claimed in claim 7, wherein the test result is further modified by the first method or the second method based on the modification of the test result by the multi-point sampling method, and the test results of the sampling points are compared to exclude outliers.

9. A noise coefficient rapid test system based on a frequency spectrograph is characterized by comprising a frequency spectrograph module, a broadband solid-state noise source and a solid-state noise source program control electrifying system;

the frequency spectrograph module is used for measuring the noise power of the unit to be measured under the working condition;

the broadband solid-state noise source is used for providing a set noise power generator to be input into the unit to be tested, enabling the frequency spectrograph module to test the noise change before and after the noise source is turned on and off, and obtaining a noise coefficient according to the change conversion;

and the solid-state noise source program control electrifying system is connected to the solid-state noise source and is used for realizing electrifying and discharging control of the solid-state noise source.

Technical Field

The invention relates to a fast noise coefficient testing method and a fast noise coefficient testing system based on a frequency spectrograph, and belongs to the technical field of wireless communication.

Background

With the popularization and development of modern wireless communication and radar, the design test and daily maintenance requirements of related radio frequency systems are more and more common. The noise coefficient is used as an important index influencing the wireless communication distance, and meanwhile, the index is most prone to generating faults in wireless communication and radar systems, so that the rapid test on the index plays an important role in guaranteeing and maintaining the radio frequency system.

In the traditional noise coefficient test, a broadband noise source needs to be accessed into a measurement system for temperature calibration before the noise coefficient test so as to correct the noise temperature of the measurement system, then a tested unit can be accessed for noise coefficient test, the noise temperature is corrected, a certain time is consumed for calibrating the system, and the test accuracy is reduced if the noise temperature is not completely eliminated.

Disclosure of Invention

In order to solve the technical problem, the invention calculates and converts the relevant noise through extracting and calculating the parameters of the frequency spectrograph equipment, thereby reducing the calibration steps and greatly improving the test accuracy and speed.

The method specifically comprises the following steps: a fast test method of noise coefficient based on a frequency spectrograph adopts the frequency spectrograph, carries out equivalent test on temperature parameters of a noise source based on a cold state and hot state mode, directly carries out noise test and algorithm correction on a unit to be tested, and finally obtains a test result of the noise coefficient.

Further, the test method comprises the following steps:

firstly, connecting a frequency spectrograph with a matched load or an open circuit, initializing a test to obtain noise power in each frequency point of the frequency spectrograph, and converting noise density;

secondly, sequentially cascading a solid-state noise source to an input port of the unit to be tested, and an output port of the unit to be tested to a radio frequency input port of a frequency spectrograph module, then selecting a non-frequency conversion or frequency conversion mode of a test mode according to the characteristics of the unit to be tested, and inputting related frequency points;

and step three, testing the noise value of the tested unit in the on and off states of the solid noise source, and converting the noise coefficient.

Further, the first step specifically comprises:

by adopting the method for testing the noise power of the frequency spectrograph, under the condition that a radio frequency port of the frequency spectrograph is not connected with other things, the noise power of the frequency spectrograph is directly obtained, the noise power density of the frequency spectrograph is further obtained, the noise power density is compared and converted with the natural noise density at the current temperature, and the noise increment is converted to obtain the equivalent test noise temperature of the frequency spectrograph.

Further, the test method comprises two test scenario modes: the device comprises a non-frequency conversion mode and a frequency conversion mode, wherein the non-frequency conversion mode and the frequency conversion mode are respectively used for realizing noise coefficient testing under frequency conversion scenes such as a receiver and the like and under non-frequency conversion scenes such as low noise amplification and the like.

Furthermore, when the output frequency of the tested unit is not equal to the input frequency, the frequency conversion mode is selected, the solid-state noise source selects the test frequency ENR to be input into the tested unit, the solid-state noise source is turned on and off, and the output of the frequency spectrograph is detected in sequence.

Furthermore, when the output frequency of the tested unit is equal to the input frequency, the non-frequency conversion mode is selected, the solid-state noise source selects the input frequency ENR to be input into the tested unit, the solid-state noise source is turned on and off, and the output of the frequency spectrograph is detected in sequence.

As a preferred embodiment of the present application, the power test of the noise is corrected in three ways, the first is averaging in the frequency domain, and the influence on the frequency of the noise fluctuation is eliminated by summing and averaging the noise test results in a continuous frequency range; the second is averaging in the time domain, and the fluctuation variation of noise fluctuation in time is eliminated by averaging the noise test results at different moments at one frequency point; the third is multipoint sampling, which samples a plurality of discrete frequency points.

Furthermore, on the basis of correcting the test result by adopting a multi-point sampling mode, the test result is further corrected by adopting the first method or the second method, and the test results of all sampling points are compared to eliminate abnormal points.

The application also provides a noise coefficient rapid test system based on the frequency spectrograph, and the test system comprises a frequency spectrograph module, a broadband solid-state noise source and a solid-state noise source program control electrifying system;

the frequency spectrograph module is used for measuring the noise power of the unit to be measured under the working condition;

the broadband solid-state noise source is used for providing a set noise power generator to be input into the unit to be tested, enabling the frequency spectrograph module to test the noise change before and after the noise source is turned on and off, and obtaining a noise coefficient according to the change conversion;

and the solid-state noise source program control electrifying system is connected to the solid-state noise source and is used for realizing electrifying and discharging control of the solid-state noise source.

Has the advantages that:

by adopting the method of the invention, when the gain of the tested unit is more than 10 dB:

a. under the noise coefficient range of 0-5 dB, the error of the measured noise coefficient is not more than 0.3 dB;

b. and under the noise coefficient range of 5-10 dB, the error of the measured noise coefficient is not more than 0.5 dB.

Based on the test method provided by the application, the noise coefficient can be quickly obtained, the test steps in the prior art are reduced from 4 steps to 2 steps, and the test time and efficiency are improved by more than 30%.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the present invention will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without inventive labor.

FIG. 1 is a block diagram of the system of the present application;

FIG. 2 is a block diagram of a test of a noisy system in a non-conversion mode;

FIG. 3 is a block diagram of the testing of noise figure in frequency conversion mode;

FIG. 4 is a schematic diagram of a system test flow.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention of this application aims to: the technical problems to be solved by the invention include 1, improving the efficiency of the traditional noise coefficient test; 2. Obtaining a method for equivalently testing the noise temperature from a frequency spectrograph; 3. and random errors introduced by noise fluctuation and the like in the test process are corrected, so that the test precision is improved. And on the basis, the noise coefficient test under the non-frequency conversion and frequency conversion modes is realized, so that the application occasion of the test method is greatly improved.

Example 1

As shown in fig. 1, the present application provides a fast noise coefficient testing system based on a spectrometer, which includes a spectrometer module, a broadband solid-state noise source, and a solid-state noise source program control power-on system;

the frequency spectrograph module is used for measuring the noise power of the unit to be measured under the working condition;

the broadband solid-state noise source is used for providing a metered noise power generator to be input to a unit to be tested, so that the frequency spectrograph module tests the front and back noise change under the conditions of opening and closing of the noise source, and obtains a noise coefficient according to the change conversion;

the solid-state noise source program control power-on system is used for realizing power-on and power-off control of the solid-state noise source.

Example 2

Based on the noise coefficient testing system, the embodiment provides a noise coefficient rapid testing method based on a frequency spectrograph, and a rapid equivalent testing noise temperature parameter extraction method of the frequency spectrograph is used for directly carrying out noise testing and algorithm correction on a tested module and finally obtaining a testing result of the noise coefficient. The method is divided into two test scene modes: and the non-frequency conversion mode and the frequency conversion mode are respectively used for realizing the noise coefficient test under the frequency conversion scenes such as a receiver and the like and under the non-frequency conversion scenes such as low noise amplification and the like.

Extracting equivalent test noise temperature of the frequency spectrograph, adopting a noise power test method of the frequency spectrograph, directly obtaining a noise power reading of the frequency spectrograph and subtracting a sub-10 logBW from the noise power reading under the condition that a radio frequency port of the frequency spectrograph is not connected with other things, wherein the BW is a resolution bandwidth of the frequency spectrograph, so as to obtain a noise power density of the frequency spectrograph, comparing and converting the noise power density with a natural noise density at the current temperature, converting a noise increment of the noise power density to obtain equivalent test noise temperature T2 of the frequency spectrograph, wherein the conversion mode is shown as a formula 1, and the noise power density of the frequency spectrograph is obtainedIn order to be the natural temperature noise power,is the spectrometer noise power.

T_S ^ON、T_S ^OFFThe noise temperatures when the solid-state noise source is turned on and when the noise source is turned off, respectively.

In the actual noise power test process, due to the randomness of noise, the power test result always fluctuates randomly, and the worst influence of the fluctuation result on the test of the noise coefficient can reach 1dB to 2dB, which can cause larger test error. It is important to algorithmically correct and statistically average the noise test results. In the method, three modes are adopted to correct the power test of the noise. The first is averaging in the frequency domain, and the influence of noise fluctuation on the frequency is eliminated by summing and averaging the noise test results in a continuous frequency range; the second is averaging in the time domain, and the fluctuation variation of noise fluctuation in time is eliminated by averaging the noise test results at different moments at one frequency point; the third is multipoint sampling, in order to prevent external burst interference and self-interference in the spectrometer, a plurality of discrete frequency points are sampled, noise test is carried out by the method 1 and the method 2, and test results of all sampling points are compared to eliminate abnormal points. Thereby obtaining a credible test result.

The test mode of the noise coefficient comprises a frequency conversion mode and a non-frequency conversion mode:

the frequency conversion mode is selected mainly according to the fact that the noise output frequency of the unit under test is not equal to the input frequency, and at this time, the user sets the frequency f1 to be tested by the unit under test. When testing the noise coefficient of the frequency conversion mode, the testing system outputs a frequency value f2 according to a set testing frequency value f1, the ENR value of the solid state noise source which is substituted into formula calculation is selected as an ENR parameter of the solid state noise source under f1, the testing of the output noise of the unit to be tested is to respectively obtain a noise measurement result when the solid state noise source is opened and a noise measurement result when the noise source is closed under the frequency point f1 by a frequency spectrograph, and then the noise measurement results are converted into related noise temperaturesAndand then converting the temperature into the noise temperature of the unit to be measured according to the formula (2), and finally converting the temperature into a noise coefficient.

The non-frequency conversion mode is selected mainly according to the fact that the output frequency of the noise tested by the tested unit is equal to the input frequency, when the noise coefficient of the non-frequency conversion mode is tested, the testing system can select the solid state noise source ENR which is brought into calculation according to the input frequency as the corresponding solid state noise source ENR parameter under the frequency, and simultaneously, the frequency spectrograph is used for respectively obtaining the noise measurement result when the solid state noise source is opened and the noise measurement result when the noise source is closed under the testing frequency.

A noise coefficient testing hardware architecture of the noise coefficient quick testing method based on the frequency spectrograph adopts a scheme of the frequency spectrograph and a solid-state noise source, and the frequency spectrograph has the following main performances:

(1) frequency range: 10MHz to 18 GHz;

(2) frequency stepping: 10 Hz;

(3) reference level range: 20dBm to-40 dBm;

(4) display noise level: less than or equal to-155 dBm/Hz;

(5) remaining false responses: less than or equal to-115 dBm/Hz.

The solid-state noise source has the following main performances:

(6) frequency range: 10MHz to 18 GHz;

(7)ENR：≥11dB。

as shown in fig. 1, fig. 2, fig. 3, and fig. 4, the present invention provides a method for quickly testing a noise coefficient based on a spectrometer. When entering a noise coefficient test mode, the spectrometer module needs to be connected in advance and self-test is carried out on the noise temperature of the spectrometer module.

After the self-checking test is finished, the user selects the number of the used solid-state noise source, and at the moment, the system automatically records an ENR coefficient table loaded with the solid-state noise source and takes the ENR coefficient table as an input parameter for calculating the noise coefficient

The user selects a noise figure test mode according to the tested unit: a non-frequency conversion mode or a frequency conversion mode.

If in the non-frequency conversion mode, at this time, the user needs to input the test frequency, and then the output port of the unit under test is connected to the input port of the frequency spectrograph, and the output port of the solid-state noise source is connected to the input port of the unit under test in the manner of fig. 2. Then click on the noise figure test. At this time, the test program calls the solid state noise source ENR at the test frequency point, and obtains the noise power at the test frequency point through the related test algorithm, and after about 10S, the interface returns the test results of the noise coefficient and the gain.

If in the frequency conversion mode, at this time, the user needs to input the input frequency and the output frequency parameters, and then the output port of the unit to be tested is connected to the input port of the frequency spectrograph and the output port of the solid-state noise source to the input port of the unit to be tested in the manner of fig. 3. Then click on the noise figure test. At this time, the test program calls the solid state noise source ENR at the input frequency point, and obtains the noise power at the output frequency point through the related test algorithm, and after about 10S, the interface returns the test results of the noise coefficient and the gain.

The whole testing process needs about 30S of time consumption, and the user only needs to connect the testing environment and input the testing parameters to obtain the result. Compared with the traditional test flow, the method needs to connect the test environment twice and is more complex in parameter setting.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.