An injection type low insertion loss broadband receiving channel online detection method

Abstract

The present application relates to a kind of injection low insertion loss wideband receiving channel online detection method, belong to wideband receiver online detection technical field.Adopt the input mode of injection wideband self-check signal, wherein wideband self-check signal includes two signal forms of continuous wave signal and modulated signal, two kinds of signals are selected by control system control operation, when input continuous wave signal, the online detection of radio frequency receiving channel can be realized, when input modulated radio frequency signal, the online detection of signal processing machine and data processing machine working state can be realized, working state information is detected and fed back in real time by detection point, complete fault alarm and report, and fault is positioned to minimum replaceable LRU, the testability and maintainability of wideband receiver are improved, and strong support is provided for system health management.

Description

Technical Field

[0001] This invention belongs to the field of online detection technology for passive radar broadband receivers. Background Technology

[0002] With the development of passive radar technology, for passive receivers, in addition to applying more advanced technologies to product design, how to improve the reliability and maintainability of the system, that is, how to more conveniently and quickly determine the working status of the system, is a key design point that needs to be fully considered at the beginning of product design.

[0003] Radar receivers require high sensitivity, large dynamic range, and suitable receiver channel gain. The wider the operating bandwidth, the more complex the functional units of the receiver become to meet the design specifications. As an injection-based online testing function, minimizing the impact on the receiver's own technical specifications while accurately determining the operating status of each functional unit in the receiver channel and isolating the smallest replaceable faulty unit are prerequisites for the design of online testing technology.

[0004] Checking the status of the receiving channel using radiated radio frequency signals requires adding a small radiating antenna. Given the compact antenna system structure, choosing a suitable installation location and antenna size is difficult. Furthermore, the radiated method introduces a significant amount of external interference signals to the receiver during testing, which is detrimental to the accurate determination of the receiver's operating status. Summary of the Invention

[0005] To address the problems mentioned in the above technical background, this invention proposes an online detection method for injection-type low insertion loss broadband receiving channels, which can be applied to the online detection of the performance status of receiver receiving channels.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A broadband self-test source, relay switch, and power detection circuit are added to the receiver's RF receiving channel. The display and control system sends a receiver self-test command to detect the RF receiving channel's operating status or the receiver's operating status. After the test is completed, a self-test shutdown command is sent, and the receiver returns to normal operating mode. The receiver's operating status detection points are the output of the low-noise amplifier unit and the frequency converter and intermediate frequency output units. The status monitoring includes fault detection of the receiving channel and status information detection feedback.

[0008] The aforementioned RF receiving channel operating status detection includes: when the receiver is working normally, the display and control system sends a self-test command, the control unit outputs a control signal for the relay switch, and the relay switch switches the RF signal source at the input end of the RF receiving channel from the feeder input to the broadband self-test signal source input; simultaneously, the control unit outputs the SPI control signal of the broadband self-test signal source to generate a continuous RF signal at the corresponding frequency point; the continuous RF signal passes through the relay switch and the low-noise amplification function unit, and at the output end of the low-noise amplification function unit, one RF signal is split and sent to the power detection circuit and detected and output; the main signal is sent to the frequency conversion and intermediate frequency output function unit, and at the output end of the intermediate frequency output function unit, one intermediate frequency signal is coupled to the power detection circuit and detected and output; the detected level value is fed back to the control unit for AD sampling and conversion into a power value; the detected power value is displayed on the status information page of the RF receiving channel, and simultaneously fed back to the health management function module, which compares it with the preset power level value to determine whether the RF receiving channel is operating normally; if the determined power level value is within the preset power level range, the system does not issue an alarm; if the determined power level value differs from the preset power level by more than the judgment threshold, the abnormal operating status is displayed on the display and control system status page;

[0009] The receiver operating status detection includes: when the receiver is working normally, the display and control system sends a self-test command, the control unit outputs a control signal for the relay switch, and the relay switch switches the RF signal source at the input end of the RF receiving channel from the feeder input to the broadband self-test signal source input; at the same time, the control unit outputs the SPI control signal of the broadband self-test signal source to generate an RF modulation signal at the corresponding frequency point; the receiver's signal processor and data processor process and obtain the frequency, period, and pulse width parameters of the input signal, which are displayed on the sorting signal display page; at the same time, they are compared with the set broadband self-test signal source modulation parameters to determine the receiver's operating status; if the frequency, period, and pulse width parameters of the processed signal are within the system's allowable error range, it is judged as normal; otherwise, abnormal status information is reported.

[0010] The online detection points for the radio frequency receiving channel are set as follows: detection point one is a power splitter at the output of the low noise amplification function unit, and detection point two is a coupling at the intermediate frequency output of the frequency conversion and intermediate frequency function unit.

[0011] The online detection method for the radio frequency receiving channel is as follows: the continuous wave signals at detection point one and detection point two are detected by the corresponding power detection circuits, and the output detection level is sent to the control unit; the control unit samples the detection level with an AD converter and calculates the power value corresponding to the level signal in the FPGA, and displays it in real time on the status display page of the display and control system.

[0012] The online detection method for receiver operating status is as follows: when the self-test mode is selected and the broadband self-test signal source outputs an RF modulation signal, the receiver obtains the frequency, period, and pulse width parameters of the input signal through signal processing and data processing, compares them with the preset modulation parameters of the self-test signal source, and determines the operating status of the receiving channel.

[0013] Furthermore, the injection method involves switching a low-insertion-loss broadband relay switch to connect the receiver input to the feed source or a broadband self-test signal source via an RF cable.

[0014] Furthermore, the low insertion loss refers to the fact that the insertion loss of the broadband relay switch is no more than 1dB within the operating frequency band.

[0015] Furthermore, the broadband self-test signal source has an output frequency range covering the DC to X bands, a frequency hopping step of 50MHz, a constant output power value, an independent fault feedback function, and output signals in the form of continuous wave signals and modulated signals, with fixed modulation parameters for the modulated signals.

[0016] The present invention adopts the above-mentioned technical solution and has the following beneficial effects:

[0017] a) Injection-based online detection, without introducing external interference during the detection process, accurately judges the working status of the receiving channel;

[0018] b) The use of relay switches for switching results in low insertion loss and minimal impact on the receiver's noise figure. Furthermore, the switch changes the operating mode of the receiver's front-end input signal source, ensuring that the receiver can still operate normally even when the self-test source malfunctions.

[0019] c) The broadband self-test signal source is small in size, low in power consumption, highly reliable, easy to control, and has independent fault feedback;

[0020] d) Set up online detection points at two nodes, the low-noise amplifier functional unit and the frequency conversion and intermediate frequency functional unit, to determine the fault point of the receiving channel with the highest efficiency and with the fewest number of configuration status detection circuits introduced. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the online detection principle of the injection-type broadband receiving channel of the present invention.

[0022] Among them: 1 is a broadband self-test signal source; 2 is a low insertion loss broadband relay switch; 3 is a low noise amplification function unit; 4 is a frequency conversion and intermediate frequency function unit; 5 is a signal processing and data processing unit; and 6 is a control unit. Detailed Implementation

[0023] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0024] To address the application requirement of periodically verifying the operating status of passive radar receivers during long-term continuous operation, this invention proposes an injection-based broadband receiving channel online detection method. Utilizing the receiver's existing receiving channel, the method manually controls the receiving channel's operating status to enter an online self-test mode, thereby determining the receiver's receiving channel's operating status and quickly and effectively locating faulty modules for repair and replacement. A schematic diagram illustrating the online detection of the operating status of the receiver-associated RF receiving channel and the receiver's overall operating status is shown below. Figure 1 As shown, by adding a broadband self-test signal source, a relay switch, a power detection circuit, and a display control terminal to the receiving channel to show the status detection results, online status detection of the passive radar receiver was achieved.

[0025] To achieve online detection of the injection-type low insertion loss receiving channel in this invention, a broadband self-test signal source is added to the input of the receiving channel. Its main function is to generate a broadband radio frequency continuous wave signal or a modulated signal to detect the status of the radio frequency receiving channel and the entire receiver. The output signal of the broadband self-test signal source is controlled by different SPI control signals generated by the display and control subsystem. In practical applications of passive radar receivers, it is necessary to ensure that the system noise figure is as low as possible. The self-test signal is input through a relay switch-injected low-noise amplification unit in the receiving channel. Due to the low insertion loss of the relay switch, the noise figure degradation introduced is minimized. The power detection circuit of the radio frequency receiving channel detects the continuous wave radio frequency signal, and the output level value is sent to the AD converter for sampling. Based on the sampled level value, the power value is calculated in the FPGA and compared with the preset power value to determine whether the gain of the receiving channel is normal. When the receiver is detecting its operating status, the broadband self-test signal source outputs an RF modulation signal. At this time, the power detection circuit of the RF channel does not detect the modulation signal. The receiver signal processing unit and data processing unit sample and sort the received modulation signal. The result is displayed on the sorting result page of the display and control system. At the same time, the frequency, pulse width and repetition period of the sorting result are compared with the set values ​​of the broadband self-test signal source. If the error exceeds the system's allowable error range, an alarm is triggered.

[0026] In the preferred implementation, the injection-type low insertion loss broadband receiving channel online detection method allows the user to select and activate the broadband self-test signal source via the control interface of the display and control subsystem. The operating mode can be selected as continuous wave output or modulated signal output, where the modulation signal has six fixed combinations of pulse width and repetition period, and the output frequency ranges from 0.1 GHz to 12 GHz, with 50 MHz increments. The control signal used to activate the self-test signal source synchronously controls the relay switch at the front end of the receiving channel, causing the relay switch to switch the input signal from the feeder input to the broadband self-test signal source input. The two are connected via an RF cable. This connection method avoids the inaccuracy caused by electromagnetic interference from radiated self-test signals. Simultaneously, the output power of the broadband self-test signal source remains constant within its operating frequency range, and the broadband self-test signal source itself has an independent fault feedback function. If its output power is abnormal or it loses lock when the broadband self-test signal source is activated, it will provide feedback to the display and control subsystem, which will display the error on the interface. When the broadband self-test function is not in use, the broadband self-test signal source is turned off by power-off to avoid insufficient isolation of the relay switch affecting the receiver's small signal reception.

[0027] The intermediate frequency (IF) signal bandwidth of a passive radar broadband receiver is typically between 500MHz and 1GHz. During self-test, the frequency output by the broadband self-test signal source is set to the radio frequency value corresponding to the center frequency of the IF signal bandwidth. The gain range of each functional unit in the receiver's radio frequency receiving channel is fixed. Simultaneously, the temperature compensation circuit in the receiving channel ensures gain compensation under full-temperature operating conditions. Therefore, for a self-test signal with constant power output, there is a defined output power detection range at each state detection point that can be used to determine whether the operating state is normal. When the broadband self-test signal source outputs a modulated signal, the receiver's signal processing unit and output processing unit display the processed signal frequency, pulse width, and repetition period. Simultaneously, they compare this value with the combination of frequency, pulse width, and repetition period selected when setting the broadband self-test signal source. If the difference meets the system's preset acceptable accuracy range, the receiver is considered to be operating normally.

[0028] Combined with appendix Figure 1 The preferred implementation steps of the present invention are as follows:

[0029] S1, the display and control system sends a receiver self-test command, which is converted into an RS-422 differential signal via a gigabit network, and then converted into an SPI control signal to control the broadband self-test signal source. The broadband self-test signal source generates an RF signal corresponding to the control signal, and the output is an RF continuous wave signal or an RF modulated signal with selectable fixed parameters;

[0030] S2, when the self-test mode is selected to be on, the relay switch switches the source of the input signal from the feeder end to the output end of the broadband self-test signal source. When the self-test mode is selected to be off, the relay switch selects the input signal to come from the feeder.

[0031] S3, when the self-test signal output is a radio frequency continuous wave signal, the output of the low noise amplification function unit splits one radio frequency signal to the power detection circuit and outputs it to the control unit. The output of the frequency converter and intermediate frequency output function unit couples one intermediate frequency signal to the power detection circuit and outputs it to the control unit. The control unit calculates the power level value corresponding to the detected level and displays it on the status information page of the display and control system. At the same time, it compares it with the preset power level range in the program to determine whether the working status of the radio frequency receiving channel is normal.

[0032] S4, when the self-test signal output is an RF modulated signal, the frequency, period, and pulse width parameters of the signal are obtained through the signal processing and data processing of the receiver. The program compares these parameters with the set broadband self-test signal source modulation parameters, and compares the difference with the system's preset acceptable accuracy range to determine the working status of the receiving channel.

[0033] Through the above design method and operation steps, the effectiveness of the present invention in monitoring the working status of the receiving channel was verified in actual installation.

[0034] The foregoing has shown and described the basic working principle, main features, and advantages of the present invention. The present invention is not limited to the above embodiments; the embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An online detection method for injection-type low insertion loss broadband receiving channels, characterized in that: A broadband self-test source, a relay switch, and a power detection circuit are added to the receiver's RF receiving channel. The display and control system sends a receiver self-test command to detect the working status of the RF receiving channel or the receiver's working status. After the test is completed, a self-test shutdown command is sent, and the receiver returns to normal working mode. The RF receiving channel operating status detection includes: the display and control system sending a self-test command; a relay switch switching the RF signal source at the input terminal of the RF receiving channel from the feeder input to the broadband self-test signal source input; simultaneously, the broadband self-test signal source generating a continuous RF wave signal at the corresponding frequency point according to the SPI control signal; after the RF continuous wave signal passes through the low-noise amplification unit, one RF signal is split and sent to the power detection circuit for detection and output; the main signal passes through the frequency conversion and intermediate frequency output unit and is coupled to one intermediate frequency signal, sent to the power detection circuit for detection and output; the detected level value is fed back to the control unit for AD sampling and conversion into a power value; the detected power value is displayed on the RF receiving channel status information page and simultaneously fed back to the health management function module for comparison with the preset power level value to determine whether the RF receiving channel is operating normally; if the detected power level value is within the preset power level range, the system does not issue an alarm; if the detected power level value differs from the preset power level by more than the judgment threshold, the operating status is displayed as abnormal on the display and control system status page; The receiver operating status detection includes: the display and control system sending a self-test command; a relay switch switching the RF signal source at the input end of the RF receiving channel from the feeder input to the broadband self-test signal source input; simultaneously, the broadband self-test signal source generating an RF modulation signal at the corresponding frequency point according to the SPI control signal; the receiver's signal processor and data processor processing the signal to obtain the frequency, period, and pulse width parameters of the input signal, displaying them on the sorting signal display page, and comparing them with the set broadband self-test signal source modulation parameters to determine the receiver's operating status; if the frequency, period, and pulse width parameters of the processed signal differ from the set modulation parameters within the system's allowable error range, it is judged as normal; otherwise, abnormal status information is reported.

2. The online detection method for injection-type low insertion loss broadband receiving channel according to claim 1, characterized in that: By switching the low insertion loss broadband relay switch, the receiver input can be connected to the feed source or the broadband self-test signal source via the RF cable. The insertion loss of the broadband relay switch is no more than 1dB within the operating frequency band.

3. The online detection method for injection-type low insertion loss broadband receiving channel according to claim 1, characterized in that: The broadband self-test signal source outputs a frequency range covering the DC to X bands, with a frequency hopping step of 50MHz, a constant output power value, and an independent fault feedback function. The output signal is available in two forms: continuous wave signal and modulated signal, with fixed modulation parameters for the modulated signal.

4. The online detection method for injection-type low insertion loss broadband receiving channel according to claim 1, characterized in that: The online detection points for the RF receiving channel are set at the output of the low-noise amplifier unit and the intermediate frequency output of the frequency converter and intermediate frequency unit. The online detection method for the RF receiving channel is as follows: the output of the low-noise amplifier unit sends one signal to the power detection circuit, and the output detection level is sent to the control unit; the intermediate frequency output of the frequency converter and intermediate frequency unit is coupled to the power detection circuit, and the output detection level is sent to the control unit. After AD sampling, the power value corresponding to the level signal is calculated in the FPGA, and the status information is fed back in real time to complete fault alarm and reporting.

5. The online detection method for injection-type low insertion loss broadband receiving channel according to claim 1, characterized in that: The receiver's operating status is detected by the following method: when the broadband self-test signal source outputs an RF modulation signal, the receiver obtains the frequency, period, and pulse width parameters of the input signal through signal processing and data processing, and compares them with the preset modulation parameters of the self-test signal source.

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