Miniaturized radio frequency comprehensive test module

Abstract

The utility model provides a miniaturized radio frequency comprehensive test module, relates to the field of radio frequency test, and solves the problem that a universal desk type radio frequency instrument has many limitations in an airborne CNI system comprehensive test scene. Wherein the radio frequency sub-module comprises a power detection unit and a frequency mixer, and the power detection unit and the frequency mixer both receive radio frequency signal input; the intermediate frequency acquisition and digital signal processing sub-module comprises a detection ADC, an intermediate frequency ADC, an audio ADC, an FPGA and a DSP, the detection ADC is connected with the power detection unit, the intermediate frequency ADC is connected with the mixer, and the audio ADC receives audio signal input; the detection ADC, the intermediate frequency ADC and the audio ADC are all connected with the FPGA, and the FPGA is also connected with the DSP; the radio frequency sub-module and the intermediate frequency acquisition and digital signal processing sub-module are integrally packaged in the shell; according to the utility model, a plurality of radio frequency testing functions are integrated, and the integrated radio frequency testing device has the advantages and characteristics of high integration, integration, miniaturization and integrated design.

Description

Technical Field

[0001] The utility model relates to the field of radio frequency testing, is applied to a radio frequency comprehensive testing process of airborne CNI equipment, and specifically relates to a miniaturized radio frequency comprehensive testing module. Background Art

[0002] In the modern aviation industry, the airborne communication, navigation and identification (CNI) system, as one of the core equipment, plays a vital role in ensuring flight safety and mission execution efficiency. With the rapid development of aviation technology, the complexity and integration of CNI systems have continued to increase, covering a variety of functional modules such as very high frequency / ultra-high frequency (V / UHF) communication, satellite communication, data link, radar transponder, navigation receiver, and friend-or-foe identification. However, effective detection methods for such highly integrated and technologically advanced airborne CNI equipment have not developed in sync with them. Existing general-purpose desktop RF instruments have exposed a series of limitations in practical applications, becoming a bottleneck restricting the testing efficiency, accuracy, and field adaptability of CNI equipment.

[0003] General-purpose desktop RF instruments are usually designed to test a specific RF parameter or function, such as measuring power, frequency, modulation characteristics, etc. This single-function design requires the use of multiple different types of instruments and frequent switching and reconfiguration when conducting a comprehensive test of airborne CNI equipment. This process is not only time-consuming and labor-intensive, but also difficult to achieve comprehensive and synchronous testing of the multi-mode, multi-protocol, and multi-band operating characteristics of CNI equipment, and cannot effectively simulate the overall performance of the equipment under actual operating conditions.

[0004] General-purpose desktop RF instruments are generally designed based on commercial standards, and have limited support for the special signal systems involved in airborne CNI systems, making them difficult to accurately analyze and process. During the test process, the lack of signal compatibility between the instrument and the device under test may cause distortion of the test results, or even make it impossible to complete the verification of certain specific functions, seriously affecting the accurate judgment of the working performance of the CNI device.

[0005] Airborne CNI equipment has extremely high requirements for the frequency measurement accuracy of pulse signals and intermittent signals, but general desktop RF instruments are limited by hardware design and algorithm optimization, making it difficult to achieve high-precision measurements of such signals at the sub-hertz level or even picosecond level. This accuracy limitation not only affects the accurate evaluation of equipment performance, but may also directly affect flight safety and mission execution results.

[0006] In view of the diversity of aviation equipment maintenance work and the particularity of the field environment, the instruments and equipment used for airborne CNI equipment testing are required to be portable and miniaturized. However, the existing general-purpose desktop RF instruments are large and heavy, and are not convenient to carry to the flight deck, maintenance workshop or field operation site for on-site testing. This not only limits the flexibility of testing work, but also increases the difficulty of equipment transportation, installation and use, and reduces the efficiency of testing work.

[0007] General desktop RF instruments also have shortcomings in terms of electromagnetic compatibility and limited protection against electromagnetic interference. At the same time, their operating temperature range, waterproof and dustproof levels, impact and vibration resistance and other indicators are difficult to meet the stringent requirements of the aviation field environment. In severe cases, they cannot even be tested normally, and the test process is affected by abnormal instrument operation. Utility Model Content

[0008] Based on the current status of the background technology, the utility model proposes a miniaturized RF comprehensive test module in order to solve the many limitations of general desktop RF instruments in the airborne CNI system comprehensive test scenario. This module is not only suitable for scientific research and production debugging in the airborne CNI equipment laboratory, but also suitable for field maintenance and testing of CNI equipment. It integrates multiple RF test functions, thereby reducing the user's use cost and improving the user's RF test efficiency.

[0009] The utility model adopts the following technical solutions to achieve the purpose:

[0010] A miniaturized radio frequency integrated test module comprises a radio frequency submodule and an intermediate frequency acquisition and digital signal processing submodule; the radio frequency submodule comprises a power detection unit and a mixer, both of which receive radio frequency signal input; the intermediate frequency acquisition and digital signal processing submodule comprises a detection ADC, an intermediate frequency ADC, an audio ADC, an FPGA and a DSP, the detection ADC is connected to the power detection unit, the intermediate frequency ADC is connected to the mixer, and the audio ADC receives an audio signal input; the detection ADC, the intermediate frequency ADC and the audio ADC are all connected to the FPGA, and the FPGA is also connected to the DSP; the radio frequency submodule and the intermediate frequency acquisition and digital signal processing submodule are integrally encapsulated in a housing.

[0011] Specifically, the intermediate frequency acquisition and digital signal processing submodule also includes a communication interface, and the DSP is connected to the host computer through the communication interface.

[0012] Preferably, the radio frequency submodule further includes an LNA unit, and the radio frequency signal is respectively input into the power detection unit and the mixer after passing through the LNA unit.

[0013] Furthermore, the radio frequency submodule also includes a tunable local oscillator unit, which is connected to the mixer; the tunable local oscillator unit is used to generate a swept frequency local oscillator signal.

[0014] Specifically, the tunable local oscillator unit includes a reference clock circuit, a frequency sweeping local oscillator circuit, a fixed local oscillator circuit and an AD clock circuit; the reference clock circuit includes a constant temperature crystal oscillator, and the constant temperature crystal oscillator is used as a reference clock for the frequency sweeping local oscillator circuit and the fixed local oscillator circuit through a phase-locked VCXO; the frequency sweeping local oscillator circuit has a broadband VCO, and the fixed local oscillator circuit has a narrowband VCO; the phase-locked loops of the frequency sweeping local oscillator circuit and the fixed local oscillator circuit both use third-order passive circuits, and the loop filtering uses third-order active filtering; the voltage-controlled oscillator of the AD clock circuit is a phase-locked loop chip with an integrated phase detector.

[0015] Furthermore, the power detection unit includes a radio frequency switch, a peak power measurement circuit and three average power measurement circuits; the radio frequency switch is connected to the FPGA for receiving radio frequency control instructions; the peak power measurement circuit is used to measure the peak power of the pulse signal, and the average power measurement circuit uses a logarithmic detection method for measuring the average power of the narrowband signal.

[0016] Preferably, the intermediate frequency acquisition and digital signal processing submodule further includes an anti-aliasing filter, and the mixer is connected to the intermediate frequency ADC via the anti-aliasing filter.

[0017] Specifically, the FPGA includes a first data forwarding unit, a second data forwarding unit, a DDC and filter extraction unit and a radio frequency control unit; the audio ADC is connected to the first data forwarding unit, the detection ADC is connected to the second data forwarding unit, and the intermediate frequency ADC is connected to the DDC and filter extraction unit; the radio frequency control unit is connected to the radio frequency sub-module for outputting radio frequency control instructions.

[0018] Specifically, the FPGA and DSP are connected via an EMIFA bus; the DSP includes an audio analysis correction unit, a power calculation correction unit, and an FFT and carrier frequency calculation unit; the audio analysis correction unit is connected to the first data forwarding unit, the power calculation correction unit is connected to the second data forwarding unit, and the FFT and carrier frequency calculation unit is connected to the DDC and filter extraction unit.

[0019] Specifically, a radio frequency interface and an audio interface are provided on the shell, the radio frequency interface is connected to the LNA unit, and the audio interface is respectively connected to the audio ADC, audio DAC and audio amplification unit through the audio channel selection unit; the audio DAC and the audio amplification unit are both connected to the FPGA.

[0020] In summary, due to the adoption of this technical solution, the beneficial effects of the utility model are as follows:

[0021] 1. Highly integrated, integrated, miniaturized and integrated design: The RF comprehensive test module of this utility model can complete the five major test functions of "power measurement, frequency measurement, audio analysis, modulation analysis and modulation frequency deviation analysis" under limited weight and volume, thereby realizing the performance test process of multi-system signals. This design not only reduces the size of the equipment, solves the portability and miniaturization problems in traditional field test assurance, but also greatly reduces the operating energy consumption and production and use costs, simplifies the operation process and external connection relationship, reduces the requirements for the user level and labor costs, and improves the reliability of the equipment.

[0022] 2. Broadband signal acquisition, high-speed signal processing and digital signal demodulation can be realized through the intermediate frequency analysis of the radio frequency integrated test module. On this basis, the utility model reduces the sampling bandwidth and can realize high-precision frequency measurement in the subsequent process.

[0023] 3. The utility model has good versatility and expansibility, and can be easily installed in various reinforced chassis, bringing the characteristics of simple operation and flexible use. Therefore, the utility model can be used as an independent modular instrument, and can also be integrated into test equipment or test systems for use, and has a wide range of usage scenarios. Due to the use of FPGA technology and DSP technology, the utility model can also smoothly realize the expansion of different functions to match the needs of actual test tasks. On this basis, the cost of the utility model is less than half of that of traditional commercial instruments of the same scale and function, so it has more potential test objects, the market size can be doubled, and the economic benefits are higher.

[0024] 4. The utility model has a wide range of environmental adaptability that can meet multiple application scenarios, and can perform electromagnetic compatibility design based on the module composition, so that the external field adaptability of the radio frequency integrated test module is stronger and the application scenarios are wider, which also brings better application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the composition structure of the radio frequency comprehensive test module of the utility model;

[0026] Figure 2 This is a schematic diagram of the composition structure of the power detection unit of the utility model;

[0027] Figure 3 It is a detailed structural diagram of the mixer and the tunable local oscillator unit of the utility model;

[0028] Figure 4 It is a schematic diagram of the composition structure of the intermediate frequency acquisition and digital signal processing submodule of the utility model;

[0029] Figure 5 It is a schematic diagram of the composition structure of the power conversion unit of the utility model;

[0030] Figure 6 It is a software hierarchy diagram of the radio frequency comprehensive test module of the utility model;

[0031] Figure 7 It is a schematic diagram of the functional structure of the DSP software of the utility model. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Generally, the components of the embodiment of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1 As shown, a miniaturized RF integrated test module includes a RF submodule and an intermediate frequency acquisition and digital signal processing submodule, and the two types of submodules are integrally encapsulated in a housing. The RF submodule includes an LNA unit, a power detection unit, a mixer, and a tunable local oscillator unit, and the intermediate frequency acquisition and digital signal processing submodule includes an audio ADC, a detection ADC, an intermediate frequency ADC, an anti-aliasing filter, an FPGA, a DSP, and a communication interface.

[0036] The power detection unit and the mixer both receive RF signal input; the detection ADC is connected to the power detection unit, the intermediate frequency ADC is connected to the mixer, and the audio ADC receives audio signal input; the detection ADC, the intermediate frequency ADC, and the audio ADC are all connected to the FPGA, and the FPGA is also connected to the DSP. The DSP is connected to the host computer via a communication interface; in this embodiment, the communication interface can be an RS422 interface.

[0037] In this embodiment, the RF submodule also includes an LNA unit. After passing through the LNA unit, the RF signal is input into the power detection unit and the mixer respectively. The LNA unit is a key component of the receiving link, which is specially designed to enhance weak RF signals and minimize the introduction of additional noise. The LNA unit plays the role of signal amplification, gain compensation and other functions. Its technology itself is a mature technology in this field and will not be described here.

[0038] The RF comprehensive test module of this embodiment has the characteristics of relatively concentrated power frequency and narrowband signal (signal bandwidth is much smaller than carrier frequency) in the waveform according to the signal type to be measured, which meets the requirements of RF bandpass sampling on signal characteristics, so the intermediate frequency acquisition uses a bandpass sampling structure. For detection acquisition and audio acquisition, since the signals to be measured are all low-frequency signals, a low-pass sampling structure is used.

[0039] The radio frequency comprehensive test module of this embodiment is used to implement measurement functions such as power measurement, frequency measurement, modulation analysis, and audio analysis, as follows:

[0040] Audio analysis function: After conditioning and collecting the external input audio signal, the FPGA forwards the data collected by the audio ADC to the DSP, where the performance indicators such as level, signal impedance, and distortion can be measured and analyzed.

[0041] Power measurement function: Power detection is performed through the power detection unit, and then the detection ADC samples the detection output signal, which is forwarded by the FPGA and sent to the DSP for power calculation and correction.

[0042] Frequency measurement function: The input RF signal is mixed into a 140MHz intermediate frequency (2M / 40M bandwidth is optional) by a mixer using a superheterodyne receiving method; since the mixer is connected to the intermediate frequency ADC through an anti-aliasing filter, the anti-aliasing filter filters out the out-of-band interference, and the intermediate frequency ADC samples the intermediate frequency bandpass signal (sampling rate 25M / 200M is optional), and then performs digital down-conversion (DDC) operation through FPGA, and finally performs FFT transformation on the baseband I and Q signals obtained by down-conversion in DSP, and measures the center frequency of the signal, which can indirectly realize the measurement of the signal frequency.

[0043] The modulation analysis and modulation frequency deviation analysis functions are also based on the baseband I and Q signals after intermediate frequency acquisition and digital down-conversion, and can be measured and analyzed in the DSP. The input RF signal in this embodiment is a RF signal of 2MHz to 5.2GHz.

[0044] Example 2

[0045] Based on Example 1, this example introduces a power detection unit in a radio frequency submodule. The power detection unit includes a radio frequency switch, a peak power measurement circuit, and three average power measurement circuits; the radio frequency switch is connected to the FPGA to receive radio frequency control instructions; the peak power measurement circuit is used to measure the peak power of the pulse signal, and the average power measurement circuit uses a logarithmic detection method to measure the average power of the narrowband signal.

[0046] Figure 2A specific structural diagram of a power detection unit of this embodiment is given, in which "960MHz~1230MHz" is the link corresponding to the peak power measurement circuit. The average power measurement circuit adopts logarithmic detection, logarithmic detection plus pre-stage pre-selection filtering, so that the average power of narrowband signals can be measured; the peak power measurement circuit actually measures the pulse peak power, and needs to collect the square wave signal after detection to restore the corresponding signal power.

[0047] In this embodiment, the RF switch selection of the power detection unit will be synchronized with the RF control command issued by the host computer to select the corresponding test channel. The power detection unit is a nonlinear device with poor temperature characteristics, and the RF integrated test module needs to have a wide temperature range. At the software level, the current temperature can be obtained through the onboard temperature sensor, and then the temperature compensation can be completed through the calibration parameter curve to achieve the expected technical indicators.

[0048] Example 3

[0049] Based on the first embodiment, this embodiment introduces the structure of a tunable local oscillator unit and a mixer. The tunable local oscillator unit is connected to the mixer; the tunable local oscillator unit is used to generate a swept frequency local oscillator signal.

[0050] The relevant circuits of the mixer serve as the pre-conditioning circuit to complete the frequency and level conversion of the RF signal from 2MHz to 5.2GHz to the intermediate frequency signal of 140MHz. In order to reduce the circuit scale and improve reliability, the secondary frequency conversion technology is used in the structure of this embodiment to generate a 6502-11702MHz swept frequency local oscillator signal, which is mixed with the input RF signal, and the difference frequency is filtered, amplified and attenuated to output the intermediate frequency signal of 140MHz, which is provided to the subsequent FPGA and DSP to complete the signal processing and analysis. As an important part of the RF submodule, the mixer has a great influence on the main technical parameters of the system, such as the signal frequency range, amplitude response flatness, and linearity index. In the design, the main indicators such as third-order intermodulation, mixing gain, port isolation, and mixing spurious are calculated and simulated to ensure its performance.

[0051] In this embodiment, the main function of the tunable local oscillator unit and the mixer circuit is to convert the 2MHz~5.2GHz RF signal to an intermediate frequency that can be effectively collected by the ADC through secondary frequency conversion. The relevant structure can be found in Figure 3 The tunable local oscillator unit includes a reference clock circuit, a frequency sweeping local oscillator circuit, a fixed local oscillator circuit and an AD clock circuit.

[0052] The reference clock circuit uses a constant temperature crystal oscillator as the high-precision and high-stability reference clock for the entire system, but its output frequency is relatively low, only 10MHz. Therefore, the reference clock frequency is increased to 100MHz through the phase-locked VCXO method, which can be used as the reference clock for the swept-frequency local oscillator circuit and the fixed local oscillator circuit, thereby improving the phase noise index of the entire system.

[0053] The swept-frequency local oscillator circuit mainly provides a variable-frequency local oscillator signal for the mixer, and is also one of the core circuits in this part of the structure. The swept-frequency local oscillator circuit may include a VCO, a phase-locked loop, a loop filter circuit, a power division circuit, an amplifier circuit, a low-pass filter circuit, and the above-mentioned reference clock circuit. Since the phase-locked frequency point is a swept-frequency local oscillator, the present embodiment uses a broadband VCO, which is conducive to simplifying the design and reducing the design difficulty; the phase-locked loop uses a third-order passive circuit; and the loop filter circuit uses a third-order active filter.

[0054] The fixed local oscillator circuit provides the local oscillator frequency for the secondary frequency conversion, which is a single-point frequency source. The fixed local oscillator circuit may also include a VCO, a phase-locked loop, a loop filter circuit, a power divider circuit, an amplifier circuit, a low-pass filter circuit and the above-mentioned reference clock circuit. Since the phase-locked frequency point is a fixed point frequency, the use of a narrow-band VCO is conducive to improving the phase noise index outside the phase-locked loop; similarly, the phase-locked loop uses a third-order passive circuit; the loop filter circuit uses a third-order active filter.

[0055] The designed output frequency of the AD clock circuit in this embodiment needs to be 200 MHz and 25 MHz, wherein the voltage-controlled oscillator is a phase-locked loop chip integrated with a phase detector.

[0056] Example 4

[0057] Based on the above embodiments, this embodiment combines Figure 1 and Figure 4 The FPGA model of this embodiment is XC7K325T, and the DSP model is SM32C6416T. Figure 4 The dual-channel ADC / 16bit shown in the figure represents Figure 1 The detection ADC and intermediate frequency ADC in the board, while the RF board represents the manifestation of the RF sub-module.

[0058] like Figure 1 As shown, the FPGA includes a first data forwarding unit, a second data forwarding unit, a DDC and filter extraction unit and a radio frequency control unit; the audio ADC is connected to the first data forwarding unit, the detection ADC is connected to the second data forwarding unit, and the intermediate frequency ADC is connected to the DDC and filter extraction unit; the radio frequency control unit is connected to the radio frequency sub-module for outputting radio frequency control instructions.

[0059] The FPGA and DSP are connected via the EMIFA bus; the DSP includes an audio analysis and correction unit, a power calculation and correction unit, and an FFT and carrier frequency calculation unit; the audio analysis and correction unit is connected to the first data forwarding unit, the power calculation and correction unit is connected to the second data forwarding unit, and the FFT and carrier frequency calculation unit is connected to the DDC and filter extraction unit.

[0060] The shell of the RF integrated test module of this embodiment is provided with a RF interface and an audio interface, the RF interface is connected to the LNA unit, and the audio interface is respectively connected to the audio ADC, audio DAC and audio amplification unit through the audio channel selection unit; the audio DAC and the audio amplification unit are both connected to the FPGA.

[0061] FPGA receives collected data through its digital interface with various ADCs, and after certain caching and down-conversion, sends the collected data to DSP through EMIFA bus for calculation and analysis. The final result is sent to the host computer through RS422 interface. The RF integrated test module also has an audio output function. Its circuit generates a fixed frequency of 1kHz and an adjustable amplitude audio signal through an audio DAC, which is output after conditioning. It also has an audio amplification function. The operational amplifier can amplify the external input audio signal by 1, 100 times, etc.

[0062] In addition, the intermediate frequency acquisition and digital signal processing submodule also integrates a power conversion unit. The structure of the power conversion unit in this embodiment can be found in Figure 5 As shown in the figure, four LDO and three DC-DC power supply chips are used.

[0063] Example 5

[0064] Based on the above embodiment, this embodiment briefly introduces the software part of the radio frequency comprehensive test module. It is designed with a friendly human-computer interactive graphical interface and software function modularization principle. The division of each functional module of the software adopts the design principle of high cohesion and low coupling, and is divided into host computer software and DSP program.

[0065] In this embodiment, the upper computer software includes an application program and a driver program. The application program implements various types of tests and their display functions. The driver program is divided into an upper-layer driver and a lower-layer driver to implement the driving function of the entire machine module.

[0066] The DSP program completes the state control of the system's specific circuits, signal acquisition, and high-speed signal measurement and analysis. The software hierarchy can be divided into the following: Figure 6 The four layers shown are:

[0067] VISA library: enables the host computer to read and write access to the address space of the RF integrated test module;

[0068] xxx.DLL: API function library, which provides the functional functions of the module, accesses DSP and FPGA registers through Visa library, and provides the application with an easy-to-understand and easy-to-call function interface.

[0069] xxx.exe, secondary development software: application layer, implements human-machine interface program by calling xxx.DLL API function.

[0070] DSP software is the core part of the RF integrated test module software and algorithm, mainly realizing measurement and analysis functions, such as power measurement, frequency measurement, audio analysis, modulation analysis, etc., which are all realized in DSP. The functional structure of DSP software can be found in Figure 7 The specific description is as follows:

[0071] System initialization: The main function is to initialize the DSP hardware working state and the parameters of each functional module after the program is started. It is divided into hardware initialization and calibration data loading according to the function;

[0072] Self-test function: After the host computer initiates the self-test command, the DSP obtains the current working temperature of the hardware module and the local oscillator lock status and reports them;

[0073] Frequency / power measurement function: The frequency / power measurement function mainly measures the frequency and power of the input channel signal and reports the results;

[0074] AM modulation depth measurement function: AM modulation depth measurement function mainly measures the modulation depth of the AM signal of the input channel and reports the result;

[0075] FM modulation frequency deviation measurement function: FM modulation frequency deviation measurement function is mainly to measure the modulation frequency deviation of the FM signal of the input channel and report the result;

[0076] Audio analysis function: The audio analysis function mainly calculates the SINAD, distortion and level amplitude of the input single tone signal and reports the results;

[0077] Audio output function: The audio output function mainly outputs 1KHz single tone signals of different amplitudes according to the configuration;

[0078] Audio amplification function: The audio amplification function is mainly used to amplify the microphone input audio;

[0079] Audio channel selection function: The audio channel selection function mainly selects the channels of two channels with five inputs to the corresponding two outputs;

[0080] MGC setting function: mainly used to set the attenuation value of the RF signal, with a maximum attenuation of 30dB.

[0081] In this embodiment, combined with the hardware and software characteristics of the radio frequency integrated test module, the frequency analysis mainly realizes 40MHz broadband signal acquisition, high-speed signal processing and digital signal demodulation. The high-speed large dynamic ADC can be used to complete 200MSps real-time analog-to-digital conversion. The FPGA in the module completes the spectrum shifting and filter design, including digital down-conversion of AD data, baseband signal demodulation, etc., which can move the signal to zero frequency and reduce the signal sampling rate (increase frequency resolution). The entire spectrum shifting and filter design includes digital mixing, NCO, low-pass filtering, CIC filtering, HB filtering, FIR filtering and other parts. Finally, the spectrum of the 2MHz bandwidth signal with a center frequency of 10MHz and the 40MHz bandwidth signal with a center frequency of 60MHz is moved to zero intermediate frequency, reducing the sampling bandwidth, and laying a good foundation for the subsequent realization of high-precision frequency measurement.

[0082] The power and frequency measurement and analysis are implemented in DSP. For power measurement, there are three categories: "constant envelope signal (LSB, USB, FM, MSK, FH, etc.)", "variable envelope continuous wave signal (AM, DS, BPSK, etc.)", and "variable envelope pulse modulation signal (TACAN, DMEP, ATC, IFF, etc.)". Different power analysis algorithms are used to measure the power of different types of signals. According to the time domain characteristics of the signal, it is classified and a variety of methods such as outlier screening, confidence classification, time domain signal retention, multiple averages to reduce the influence of noise are used to achieve high-precision measurement of power.

[0083] For frequency measurement, according to different signal spectrum characteristics, several different algorithms can be used, such as direct peak frequency measurement method, indirect peak frequency measurement method, centroid frequency measurement method, amplitude combined frequency measurement method, etc. At the same time, in order to further improve the measurement accuracy, some algorithm processing measures are adopted: spectrum trajectory averaging, dynamic convergence based on dichotomy. When performing FFT spectrum analysis on spectrally symmetrical signals, the selection of the spectrum center may be affected by the presence of noise. Therefore, this embodiment can adopt a spectrum trajectory smoothing method, that is, averaging the spectrum of multiple FFT outputs to offset the randomness of the noise, thereby making the trajectory of the spectrum output smoother, which is conducive to the estimation of the spectrum centroid.

[0084] The frequency band to be tested is divided into frequency bands according to the maximum filter bandwidth, and then the binary method is used to dynamically converge the frequency band range, and the method of reducing the sampling rate and secondary frequency conversion is used to improve the frequency measurement accuracy. It solves the problem that the frequency sweep speed of the pulse modulation signal spectrum analysis is slow, it is difficult to capture the signal, and thus it is impossible to measure the frequency; it also solves the problem that the signal with non-single peak value cannot use the method of locating the peak value to accurately measure the frequency.

[0085] Combined with the software part of the RF integrated test module introduced in this embodiment, and based on the structural design of the RF integrated test module, each component has achieved miniaturization and integration. The recommended module size is 233mm×160mm×35mm, and the weight is 2.5kg; at the same time, it adopts a reinforced design with locking strips, which is convenient for installation in various reinforced chassis. By defining the module functions by software, the module also has strong scalability. Without changing the hardware structure, only the intermediate frequency analysis of the FPGA and the algorithm design software of the DSP are changed or added, thereby realizing the expansion of different functions.

Claims

1. A miniaturized radio frequency integrated test module, characterized in that: It includes a radio frequency submodule and an intermediate frequency acquisition and digital signal processing submodule; the radio frequency submodule includes a power detection unit and a mixer, both of which receive radio frequency signal input; the intermediate frequency acquisition and digital signal processing submodule includes a detection ADC, an intermediate frequency ADC, an audio ADC, an FPGA and a DSP, the detection ADC is connected to the power detection unit, the intermediate frequency ADC is connected to the mixer, and the audio ADC receives audio signal input; the detection ADC, the intermediate frequency ADC and the audio ADC are all connected to the FPGA, and the FPGA is also connected to the DSP; the radio frequency submodule and the intermediate frequency acquisition and digital signal processing submodule are encapsulated as a whole in a shell.

2. A miniaturized radio frequency integrated test module according to claim 1, characterized in that: The intermediate frequency acquisition and digital signal processing submodule also includes a communication interface, and the DSP is connected to the host computer through the communication interface.

3. The miniaturized radio frequency integrated test module according to claim 1, characterized in that: The radio frequency submodule also includes an LNA unit. After passing through the LNA unit, the radio frequency signal is input into the power detection unit and the mixer respectively.

4. The miniaturized radio frequency integrated test module according to claim 1, characterized in that: The radio frequency submodule also includes a tunable local oscillator unit, which is connected to the mixer; the tunable local oscillator unit is used to generate a swept frequency local oscillator signal.

5. A miniaturized radio frequency integrated test module according to claim 4, characterized in that: The tunable local oscillator unit includes a reference clock circuit, a frequency sweeping local oscillator circuit, a fixed local oscillator circuit and an AD clock circuit; the reference clock circuit includes a constant temperature crystal oscillator, which is used as a reference clock for the frequency sweeping local oscillator circuit and the fixed local oscillator circuit through a phase-locked VCXO; the frequency sweeping local oscillator circuit has a broadband VCO, and the fixed local oscillator circuit has a narrowband VCO; the phase-locked loops of the frequency sweeping local oscillator circuit and the fixed local oscillator circuit both use a third-order passive circuit, and the loop filters of the frequency sweeping local oscillator circuit and the fixed local oscillator circuit both use a third-order active filter; the voltage-controlled oscillator of the AD clock circuit is a phase-locked loop chip with an integrated phase detector.

6. The miniaturized radio frequency integrated test module according to claim 1, characterized in that: The power detection unit includes an RF switch, a peak power measurement circuit and three average power measurement circuits; the RF switch is connected to the FPGA to receive RF control instructions; the peak power measurement circuit is used to measure the peak power of the pulse signal, and the average power measurement circuit uses a logarithmic detection method to measure the average power of the narrowband signal.

7. The miniaturized radio frequency integrated test module according to claim 1, characterized in that: The intermediate frequency acquisition and digital signal processing submodule also includes an anti-aliasing filter, and the mixer is connected to the intermediate frequency ADC through the anti-aliasing filter.

8. The miniaturized radio frequency integrated test module according to claim 1, characterized in that: The FPGA includes a first data forwarding unit, a second data forwarding unit, a DDC and filter extraction unit and a radio frequency control unit; the audio ADC is connected to the first data forwarding unit, the detection ADC is connected to the second data forwarding unit, and the intermediate frequency ADC is connected to the DDC and filter extraction unit; the radio frequency control unit is connected to the radio frequency sub-module for outputting radio frequency control instructions.

9. The miniaturized radio frequency integrated test module according to claim 8, characterized in that: The FPGA and DSP are connected via the EMIFA bus; the DSP includes an audio analysis and correction unit, a power calculation and correction unit, and an FFT and carrier frequency calculation unit; the audio analysis and correction unit is connected to the first data forwarding unit, the power calculation and correction unit is connected to the second data forwarding unit, and the FFT and carrier frequency calculation unit is connected to the DDC and filter extraction unit.

10. The miniaturized radio frequency integrated test module according to claim 3, characterized in that: The shell is provided with a radio frequency interface and an audio interface, the radio frequency interface is connected to the LNA unit, and the audio interface is respectively connected to the audio ADC, audio DAC and audio amplification unit through the audio channel selection unit; the audio DAC and the audio amplification unit are both connected to the FPGA.

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