CN105067894A - Method and system of testing frequency conversion loss of mixer - Google Patents

Abstract

The invention relates to a testing method and testing system for frequency conversion loss of a mixer. The test method of the frequency conversion loss of the mixer includes setting the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer; communicating with the test instrument, driving the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters RF signal; obtain the test data returned by the test instrument, where the test data is the intermediate frequency signal power output by the mixer according to the local oscillator frequency signal and the RF signal after mixing; calculate the ratio of the RF signal power corresponding to the application parameters to the test data , to get the conversion loss value. Therefore, the automatic test of the frequency conversion loss of the mixer is realized, the manual labor intensity is reduced, and the efficiency is improved.

Description

Method and system for testing frequency conversion loss of mixer

technical field

The invention relates to the technical field of instrument performance testing, in particular to a testing method and system for frequency conversion loss of a mixer.

Background technique

The mixer mixes two input signals of different frequencies into an output signal of a specific frequency to realize the frequency conversion function. As an important part of a receiver or other equipment, the performance of the mixer directly affects the parameters of the equipment and instruments, especially the frequency conversion loss of the mixer, which has a very important impact on the working status of the entire equipment. Frequency conversion loss is defined as the ratio of the power of the input frequency to the power of the output frequency at a given LO (LocalOscillator local oscillator frequency), which is a measure of how effectively the mixer converts the input frequency energy into the output frequency energy, where the input frequency It is RF (RadioFrequency radio frequency), and the output frequency is IF (IntermediateFrequency intermediate frequency).

The frequency conversion loss test of the mixer is affected by the matching between LO, RF and ports, and the test is difficult. Traditional conversion loss testing methods include: using test instruments such as power meters, spectrum analyzers, or vector network analyzers. Using a power meter and a spectrum analyzer to test the frequency conversion loss requires the use of two signal sources, a power meter or a spectrum analyzer, and a function signal generator. Using a vector network analyzer to test the frequency conversion loss requires a two-port vector network analyzer and a signal source or a four-port vector network analyzer with two excitation sources inside, both of these two test methods require manual switching and setting of various instruments, and subsequent manual processing of test values is required, which is time-consuming and laborious. Therefore, the traditional testing method of conversion loss is not efficient.

Contents of the invention

Based on this, it is necessary to provide a high-efficiency mixer frequency conversion loss testing method and system to address the above problems.

A method for testing the frequency conversion loss of a mixer, comprising the steps of:

Set the application parameters corresponding to the local oscillator frequency signal and radio frequency signal of the mixer;

Communicating with the test instrument, driving the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters;

Obtain the test data returned by the test instrument, wherein the test data is the intermediate frequency signal power output by the mixer according to the local oscillator frequency signal and the radio frequency signal after mixing processing;

Calculate the ratio of the radio frequency signal power corresponding to the application parameter to the test data to obtain a frequency conversion loss value.

A test system for frequency conversion loss of a mixer, comprising:

The parameter setting module is used to set the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer;

The drive test module is used to communicate with the test instrument, and drive the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters;

The data acquisition module is used to obtain the test data returned by the test instrument, wherein the test data is the intermediate frequency signal power output by the mixer according to the local oscillator frequency signal and the radio frequency signal after mixing processing;

The data processing module is used to calculate the ratio of the radio frequency signal power corresponding to the application parameter and the test data to obtain the frequency conversion loss value.

The above-mentioned method and system for testing the frequency conversion loss of a mixer, by driving the test instrument to input the corresponding radio frequency signal and the local oscillator frequency signal to the mixer according to the application parameters, and obtaining the test of the mixed frequency output of the mixer returned by the test instrument Data, and calculate the ratio of the RF signal corresponding to the application parameters and the test data to obtain the frequency conversion loss value, which realizes the automatic test of the frequency conversion loss of the mixer, reduces the labor intensity and improves the efficiency.

Description of drawings

Fig. 1 is the flow chart of the testing method of frequency conversion loss of mixer of the present invention in one of them embodiment;

Fig. 2 is the flow chart of the testing method of frequency conversion loss of the mixer in another embodiment;

Fig. 3 is a flow chart of setting the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer in an embodiment;

Fig. 4 is the block diagram of the testing system of mixer frequency conversion loss of the present invention;

Fig. 5 is the connection schematic diagram of test instrument and mixer in an embodiment;

Fig. 6 is the block diagram of the test system of the frequency conversion loss of the mixer in another embodiment;

Fig. 7 is a specific unit diagram of the communication test module in an embodiment;

Fig. 8 is a specific unit diagram of a parameter setting module in an embodiment;

Fig. 9 is a test device diagram of a test system using a frequency conversion loss of a mixer;

Figure 10 is a module block diagram of the communication sub VI;

Figure 11 is a program block diagram of the communication subVI;

Figure 12 is a schematic diagram of the interface of the instrument driver sub-VI;

Fig. 13 is a schematic diagram of the login interface of the software running on the computer.

Detailed ways

Referring to FIG. 1 , a method for testing frequency conversion loss of a mixer according to an embodiment of the present invention includes steps S110 to S170 .

S110: Setting application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer.

For example, the staff can manually input the number of frequency points corresponding to the local oscillator frequency signal and the radio frequency signal that need to be set, indicating the corresponding local oscillator frequency signal and radio frequency signal.

S130: communicating with the test instrument, driving the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters.

The test instrument refers to the instrument used to test the frequency conversion loss value of the mixer. For example, test equipment can include a two-port vector network analyzer and a signal source. In this embodiment, one port of the vector network analyzer is connected to the radio frequency signal input port of the mixer for providing radio frequency signals, and the other port is connected to the intermediate frequency signal output port of the mixer, and the signal source is connected to the local oscillator frequency signal for It is used to provide the local oscillator frequency signal to the mixer. It can be understood that in other embodiments, the test instrument may also be a four-port vector network analyzer with two excitation sources. In this case, the vector network analyzer provides both radio frequency signals and local oscillator frequency signals.

S150: Obtain the test data returned by the test instrument, wherein the test data is the power of the intermediate frequency signal output by the mixer after mixing according to the local oscillator frequency signal and the radio frequency signal.

S170: Calculate the ratio of the radio frequency signal power corresponding to the application parameter to the test data to obtain a frequency conversion loss value.

In one embodiment, referring to FIG. 2 , step S110 also includes step S100 before step S110 : detecting whether the communication with the testing instrument is normal, and if so, executing step S110 . If not, an alarm signal can be sent to inform the staff of the communication failure, so as to deal with it in time. By detecting whether the communication connection is normal in advance, the possibility of not receiving the data returned by the test instrument is eliminated, and the efficiency is improved.

In one embodiment, step S100 includes step s11 to step s13.

s11: Send test data to the test instrument. For example, detection data may be frequency points.

s12: judging whether the feedback data obtained by the test instrument in response to the detection data is received. If yes, execute step s13.

s13: Judging that the communication with the testing instrument is normal.

In one embodiment, referring to FIG. 3 , step S110 includes step S111 to step S119 .

S111: Obtain the input user name and user password.

S113: Determine whether the input user name is stored. If yes, execute step S115.

S115: Determine whether the input user password is consistent with the password corresponding to the stored user name. If yes, execute step S117 or execute step S119.

The input user name is stored, indicating that the user is allowed to log in to the system. When the entered user password is consistent with the password corresponding to the stored user name, it means that the user has passed the authentication and can use the system. Specifically, if the input user password is inconsistent with the password corresponding to the stored user name, a prompt message may be output to notify the user to re-enter the user password.

Through the verification of user name and user password, a user name and user password correspond to a folder, so that when multiple people use the system, it can avoid mutual interference of tests, avoid relevant testers from making mistakes in testing, and prevent irrelevant personnel from using the system.

S117: Receive an input parameter corresponding to the user name, and set the parameter as an application parameter. Therefore, after the user logs in, the application parameters can be reset.

S119: According to the user name, acquire the stored parameters corresponding to the user name, and set the parameter with the latest storage time among the stored parameters as the application parameter. That is, the parameter corresponding to the user name may be called and set as an application parameter, specifically calling the application parameter last set by the user. Therefore, when the user logs in to the system, the last test can be continued.

In one embodiment, in step S130, after communicating with the test instrument, before driving the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters, it also includes: sending calibration data to the test instrument, Receiving the data returned by the test instrument in response to the calibration data, judging whether the error between the calibration data and the returned data is less than or equal to the preset error value, and if so, executing the driving test instrument to input the corresponding local oscillator frequency to the mixer according to the application parameters Signal and RF signal steps. If not, continue to send the calibration data until the error value between the calibration data and the returned data is less than or equal to the preset error value. Through instrument calibration, the accuracy of data transmission is improved.

In one embodiment, referring to FIG. 2 , after step S170 , step S190 is further included: comparing the conversion loss value with a preset index to obtain a performance analysis report of the mixer.

The preset index refers to the ideal frequency conversion loss value corresponding to a radio frequency signal in a frequency band. Comparing the measured frequency conversion loss value with the frequency conversion loss value in the preset index, the performance of the mixer can be obtained.

It can be understood that there may be multiple sets of application parameters set in step S110, and correspondingly, one frequency conversion loss value in step S170 may be obtained for each set of application parameters. Through the test of multiple frequency conversion loss values, the frequency conversion loss in each frequency band can be obtained, so as to conduct a comprehensive performance evaluation. In this embodiment, the performance analysis report may be a graph with the frequency value on the horizontal axis and the frequency conversion loss value on the vertical axis.

In one embodiment, after step S190, a step of storing frequency conversion loss values and/or performance analysis reports is further included. Store the data obtained from the test, so that the staff can check the statistics in the future.

The above-mentioned method for testing the frequency conversion loss of a mixer, by driving the test instrument to input the corresponding radio frequency signal and the local oscillator frequency signal to the mixer according to the application parameters, to obtain the test data of the mixer output by the mixer returned by the test instrument, And calculate the ratio of the radio frequency signal corresponding to the application parameters and the test data to obtain the frequency conversion loss value, realize the automatic test of the frequency conversion loss of the mixer, reduce the labor intensity and improve the efficiency.

Referring to FIG. 4 , a test system for frequency conversion loss of a mixer according to an embodiment of the present invention includes a parameter setting module 110 , a driving test module 130 , a data acquisition module 150 and a data processing module 170 .

The parameter setting module 110 is used to set the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer 200 (see FIG. 5 ). For example, the staff can manually input the number of frequency points corresponding to the local oscillator frequency signal and the radio frequency signal that need to be set, indicating the corresponding local oscillator frequency signal and radio frequency signal.

The drive test module 130 is used to communicate with the test instrument 300 (see FIG. 5 ), and the drive test instrument 300 inputs a corresponding local oscillator frequency signal and a radio frequency signal to the mixer 200 according to application parameters.

The test instrument 300 refers to an instrument for testing the frequency conversion loss value of the mixer 200 . For example, referring to FIG. 5 , the test instrument 300 may include a two-port vector network analyzer 301 and a signal source 320 . In this embodiment, one port of the vector network analyzer 301 is connected to the radio frequency signal input port of the mixer 200 for providing radio frequency signals, the other port is connected to the intermediate frequency signal output port of the mixer 200, and the signal source 302 is connected to the local oscillator The frequency signal is used to provide a local oscillator frequency signal to the mixer 200 . It can be understood that, in other embodiments, the test instrument 300 may also be a four-port vector network analyzer with two excitation sources. In this case, the four-port vector network analyzer provides both radio frequency signals and local oscillator frequency signals.

The data acquisition module 150 is used to acquire the test data returned by the test instrument 300, wherein the test data is the power of the intermediate frequency signal output by the mixer 200 after mixing according to the local oscillator frequency signal and the radio frequency signal.

The data processing module 170 is used to calculate the ratio of the radio frequency signal power corresponding to the application parameters and the test data to obtain the frequency conversion loss value.

In one embodiment, referring to FIG. 6 , the above-mentioned mixer frequency conversion loss testing system further includes a communication testing module 100 for detecting whether the communication with the testing instrument 300 is normal. If the communication is normal, the test operation can be performed normally. If not, an alarm signal can be sent to inform the staff of the communication failure, so as to deal with it in time. By detecting whether the communication connection is normal in advance, the possibility of not receiving the data returned by the testing instrument 300 is eliminated, and the efficiency is improved.

In one of the embodiments, referring to FIG. 7, the communication test module 100 includes:

The data sending unit 101 is configured to send detection data to the test instrument 300 . For example, detection data may be frequency points.

The data receiving unit 103 is used for judging whether to receive the feedback data obtained by the test instrument 300 in response to the detection data.

The result judging unit 105 is configured to judge that the communication with the testing instrument 300 is normal when the feedback data is received.

In one of the embodiments, referring to FIG. 8 , the parameter setting module 110 includes a user ID collecting unit 111 , a user ID identifying unit 113 and a user parameter setting unit 115 .

The user identification collecting unit 111 is used to obtain the input user name and user password. The user name and user password are used when logging into the system.

The user identification recognition unit 113 is used to determine whether the input user name is stored, and if so, determine whether the input user password is consistent with the password corresponding to the stored user name. The input user name is stored, indicating that the user is allowed to log in to the system. When the entered user password is consistent with the password corresponding to the stored user name, it means that the user has passed the authentication and can use the system. Specifically, if the input user password is inconsistent with the password corresponding to the stored user name, a prompt message may be output to notify the user to re-enter the user password.

Through the verification of user name and user password, a user name and user password correspond to a folder, so that when multiple people use the system, it can avoid mutual interference of tests, avoid relevant testers from making mistakes in testing, and prevent irrelevant personnel from using the system.

The user parameter setting unit 115 is configured to receive the input parameter corresponding to the user name when the input user password is consistent with the password corresponding to the stored user name, and set the parameter as an application parameter. Therefore, after the user logs in, the application parameters can be reset. Alternatively, the user parameter setting unit 115 may also be configured to obtain stored parameters corresponding to the user name according to the user name, and set the parameter with the latest storage time among the stored parameters as the application parameter. That is, the system may call the parameter corresponding to the stored user name and set it as an application parameter, specifically calling the application parameter last set by the user. Therefore, when the user logs in to the system, the last test can be continued.

In one embodiment, the drive test module 130 includes a calibration unit (not shown) and a test unit (not shown). The calibration unit is used to communicate with the test instrument 300, send calibration data to the test instrument 300, receive the data returned by the test instrument 300 in response to the calibration data, and determine whether the error between the calibration data and the returned data is less than or equal to the preset error value. The test unit is used to drive the test instrument 300 to input the local oscillator frequency signal and the radio frequency signal to the mixer 200 according to the application parameters when the error between the calibration data and the returned data is less than or equal to the preset error value. Specifically, if the error between the calibration data and the returned data is greater than a preset error value, continue to send the calibration data until the error between the calibration data and the returned data is less than or equal to the preset error value. Through instrument calibration, the accuracy of data transmission is improved.

In one embodiment, continue to refer to FIG. 6, the above-mentioned mixer frequency conversion loss testing system further includes a performance analysis module 180, which is used to compare the frequency conversion loss value with a preset index, and obtain the performance analysis of the mixer 200. Report. The preset index refers to the ideal frequency conversion loss value corresponding to a radio frequency signal in a frequency band. By comparing the measured frequency conversion loss value with the frequency conversion loss value in the preset index, the performance of the mixer 200 can be obtained, so that the performance evaluation of the tested mixer 200 can be performed.

It can be understood that there may be multiple sets of application parameters set in the parameter setting module 110, and correspondingly, a frequency conversion loss value may be obtained for each set of application parameters. Through the test of multiple frequency conversion loss values, the frequency conversion loss in each frequency band can be obtained, so as to conduct a comprehensive performance evaluation. In this embodiment, the performance analysis report may be a graph with the frequency value on the horizontal axis and the frequency conversion loss value on the vertical axis.

In one embodiment, the above-mentioned mixer frequency conversion loss testing system further includes an output module (not shown in the figure), and the output module is used to output a performance analysis report of the mixer 200 . Store the data obtained from the test, so that the staff can check the statistics in the future.

In one embodiment, referring to FIG. 6 , the above-mentioned mixer frequency conversion loss testing system further includes a storage module 190 for storing frequency conversion loss values and/or performance analysis reports.

The above-mentioned test system for frequency conversion loss of a mixer, drives the test instrument 300 through the drive test module 130 to input the corresponding radio frequency signal and local oscillator frequency signal to the mixer 200 according to the application parameters set by the parameter setting module 110, and the data acquisition module 150 obtains the test data outputted by the mixer 200 mixed frequency returned by the test instrument 300, and the data processing module 170 calculates the ratio of the radio frequency signal corresponding to the application parameter and the test data to obtain the frequency conversion loss value, thereby realizing the automatic test of the frequency conversion loss of the mixer 200 , Reduce labor intensity and improve efficiency.

Taking the test system applying the frequency conversion loss of the above-mentioned mixer as an example, the test device of the test system using the above-mentioned frequency conversion loss of the mixer is shown in FIG. 9 .

The test device for the frequency conversion loss of the mixer is based on LabVIEW, which mainly consists of two parts: hardware and software. The hardware part includes corresponding test instruments, computers and data output devices. The test instrument mainly consists of two parts: a vector network analyzer with a frequency offset test module and a signal source with the function of sweeping frequency, setting the number of sweeping points, sweeping time and receiving an external trigger signal. The computer uses the XP system that can support the GPIB interface driver. The data output device completes the data transmission between the data output device and the computer through the GPIB bus. Specifically, the data output device may be a printer device.

The test instrument mainly refers to the hardware test equipment used to measure the frequency conversion loss parameters of the mixer. It can be composed of a two-port vector network analyzer with frequency offset function and a signal source with frequency sweep function, or a direct one with two excitation sources inside. Four-port vector network analyzer complete. In this set of devices, Agilent's N5230A series is selected as the vector network analyzer. This series of models has high-performance receivers, large test dynamic range, high test accuracy, fast test speed, multi-channel test function, and flexible configuration of test structures. A variety of bus test control methods. The signal source is selected from Agilent's E8257D series, which has fast frequency sweep speed and high precision, and can receive an external trigger signal to drive the signal source. During the test, the P1 port of the vector network analyzer is used as the output port of the vector network analyzer to input the signal for the RF port of the mixer, and the P2 port is connected to the IF port of the mixer as the input port of the vector network analyzer to display the signal Change, the local oscillator port of the mixer is connected to the output port of the signal source E8257D. The frequency conversion loss measurement of the mixer must ensure that the test results are accurate and reliable under the premise that the signals of the two instruments are at the same frequency. A BNC line is required to connect the vector network analyzer and the external trigger input of the signal source, and the two instruments are given externally. The trigger signal of the instrument operation completes the same frequency measurement.

The computer is mainly used to make the designed software run normally, control the measuring instrument and collect and store data. The computer configuration requires the operating system to be XP system and above, and the external interface should support GPIB bus and LPT port. The reason why the computer supports the GPIB interface is that the general-purpose instruments are equipped with a GPIB port, which is conducive to the expansion of the instrument and online testing. The computer supports the GPIB interface, which is also conducive to reducing the test cost, and does not need to add other communication lines. Low cost, complete technology, simple development, strong versatility. The LPT port is a computer connected to a printer device, mainly for output and display of test data after processing, and to issue a paper version of the test data carrier, reducing the workload of testers for later data processing.

The software part of the mixer frequency conversion loss test device based on LabVIEW (LaboratoryVirtualInstrumentationEngineeringWorkbench, laboratory virtual instrument engineering platform) consists of four parts: communication subVI for communicating with GPIB equipment, instrument driver subVI, signal acquisition and processing subVI, processing Interfaces of each layer and subVIs for implementing multimedia technology.

Referring to Figure 10, it is a block diagram of the communication sub VI. There are two ways of GPIB programming on the LabVIEW platform, namely the traditional GPIB way and the VISA way for the plug and play protocol (VXIplug&play). In this application example, VISA programming is adopted. VISA is the abbreviation of virtual instrument software structure system, which is a single-interface program library that controls VXI, GPIB, RS-232 and other types of instruments on the LabVIEW platform. Adopting the VISA standard can ignore the time and instrument I/0 options, and the drivers can be used compatible with each other. Most VISA function modules use VISAsession parameters, and VISAsession is a unique logical identifier for each program operation. It identifies the name of the device to communicate with and the configuration information necessary for I/O operations. The communication sub-VI includes the following functions: VISAOpen (open the communication process), VISAWrite (write the data string into the specified device), VISARead (read the data from the specified device), VISAClose (close the communication process of the device specified by VISAsession, release the system resources) and other functional modules. Each module is composed of corresponding functions. This function directly calls the above four functions in the serial port option of the instrument I/O assistant in the program block diagram of the LabVIEW language, in the order of opening, writing, reading and closing programming. Referring to Figure 11, it is the program block diagram of the communication subVI.

Referring to Figure 12, it is a schematic diagram of the interface of the instrument driver sub VI. Virtual instrument driver is a kind of software that handles control communication with specific instruments. It is the link and bridge for users to complete the control of instrument hardware. Instrument image. The core of the virtual instrument driver is the driver function VI set (that is, the subroutines that make up the driver module). The driver is generally divided into two layers: the bottom layer is the basic operation of the instrument, such as initializing the instrument, configuring the input parameters of the instrument, sending and receiving data, and checking the status of the instrument; the high layer is the application function/VI layer, which calls the bottom function VI according to the specific measurement requirements, and correspondingly The functions are selected in the program block diagram programming, such as numerical input, initialization of instruments and other functions. The process of using the computer to control the instrument is actually the process of information transmission between the computer and the instrument in the communication process, which is the command to control the instrument and the feedback data of the instrument. Each instrument has its specific command and sending command format, which need to be written according to the corresponding instrument operating instructions. Each different instrument can be driven by downloading the corresponding driver.

The signal acquisition and processing subVI mainly reads out the required data according to the user's test requirements and the command format related to instrument data acquisition. Through the data collection of LabVIEW and the function of converting the original data into an excel document through a certain function VI, the time of data processing is directly saved, and the workload of the testers is effectively reduced. For example, when collecting the data of the frequency conversion loss measurement process, first set the data items to be collected, then send the read data command to collect the data, and finally read the data and transmit it to the computer through GPIB for subsequent processing.

In the development of virtual instrument software, the modular programming method is generally adopted. The starting point of modular programming is to decompose a complex system software into several functional modules, and each module performs a single function. In the programming design of this system, the sub VIs that deal with interfaces of various layers and realize multimedia technology first compile various subroutine VIs based on functions, including instrument initialization, function selection, data collection and processing, error query, etc., and then compile Call the high-level subVIs of these functional modules to complete complex data collection and processing tasks.

Referring to FIG. 13 , it is the login interface of running software on the computer. After the user logs in, the software can realize the communication with the test instrument and drive the test instrument for testing.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a method for testing of mixer frequency conversion loss, is characterized in that, comprises the steps: Set the application parameters corresponding to the local oscillator frequency signal and radio frequency signal of the mixer; Communicating with the test instrument, driving the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters; Obtain the test data returned by the test instrument, wherein the test data is the intermediate frequency signal power output by the mixer according to the local oscillator frequency signal and the radio frequency signal after mixing processing; Calculate the ratio of the radio frequency signal power corresponding to the application parameter to the test data to obtain a frequency conversion loss value. 2. the test method of mixer frequency conversion loss according to claim 1, is characterized in that, before the local oscillator frequency signal of described setting mixer and the application parameter corresponding to radio frequency signal, also comprise: Detecting and judging whether the communication with the testing instrument is normal; If yes, execute the step of setting the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer. 3. the test method of mixer frequency conversion loss according to claim 2, is characterized in that, whether described detection judges and the communication of described testing instrument is normal, comprises: sending detection data to the testing instrument; judging whether the feedback data obtained by the test instrument in response to the detection data is received; If yes, it is determined that the communication with the test instrument is normal. 4. the method for testing of mixer frequency conversion loss according to claim 1, is characterized in that, the application parameter corresponding to the local oscillator frequency signal of described setting mixer and radio frequency signal comprises: Obtain the entered username and password; Determine whether the input username is stored; If so, determine whether the input user password is consistent with the password corresponding to the stored user name; If they are consistent, receive input parameters corresponding to the user name, and set the parameters as the application parameters; or According to the user name, the stored parameters corresponding to the user name are obtained, and the parameter with the latest storage time among the stored parameters is set as the application parameter. 5. the test method of frequency conversion loss of mixer according to claim 1, is characterized in that, described calculating the ratio of the radio frequency signal power corresponding to described application parameter and test data, after obtaining frequency conversion loss value, also comprises: The frequency conversion loss value is compared with a preset index to obtain a performance analysis report of the mixer. 6. A test system for frequency conversion loss of a mixer, characterized in that it comprises: The parameter setting module is used to set the application parameters corresponding to the local oscillator frequency signal and the radio frequency signal of the mixer; The drive test module is used to communicate with the test instrument, and drive the test instrument to input the corresponding local oscillator frequency signal and radio frequency signal to the mixer according to the application parameters; The data acquisition module is used to obtain the test data returned by the test instrument, wherein the test data is the intermediate frequency signal power output by the mixer according to the local oscillator frequency signal and the radio frequency signal after mixing processing; The data processing module is used to calculate the ratio of the radio frequency signal power corresponding to the application parameter and the test data to obtain the frequency conversion loss value. 7 . The test system for frequency conversion loss of the mixer according to claim 6 , further comprising a communication test module for detecting whether the communication with the test instrument is normal. 7 . 8. The test system of the frequency conversion loss of the mixer according to claim 7, wherein the communication test module comprises: a data sending unit, configured to send detection data to the test instrument; a data receiving unit, configured to determine whether the feedback data obtained by the test instrument in response to the detection data is received; The result judging unit is configured to judge that the communication with the test instrument is normal when the feedback data is received. 9. the test system of mixer conversion loss according to claim 6, is characterized in that, described parameter setting module comprises: A user identification acquisition unit, configured to acquire an input user name and user password; The user identification recognition unit is used to judge whether the input user name is stored, and if so, judges whether the input user password is consistent with the password corresponding to the stored user name; A user parameter setting unit, configured to receive an input parameter corresponding to the user name when the input user password is consistent with the password corresponding to the stored user name, and set the parameter as the application parameter; or The method is used for obtaining the stored parameters corresponding to the user name according to the user name, and setting the parameter with the latest storage time among the stored parameters as the application parameter. 10. The test system of the frequency conversion loss of the mixer according to claim 6, further comprising a performance analysis module, which is used to compare and process the frequency conversion loss value and a preset index to obtain the frequency conversion loss of the mixer performance analysis report.