A directional audio signal detection device and method based on FFT
Through the directional audio signal detection device based on FFT, the validity of the directional instrument signal is automatically judged using modular signal processing technology, and the problem of artificial judgment dependence in the prior art is solved, and efficiency and accuracy are improved.
Patent Information
- Application Number
- CN201711478223.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2017-12-29
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2037-12-29
AI Technical Summary
In the prior art, the effective directional signal judgment of the directional instrument relies on artificial hearing, requires pilots to have high technical level, and there is a problem of waste of manpower and material resources.
Using the directional audio signal detection device based on FFT, the directional antenna, reception unit, control unit and display are used to perform radio frequency signals using the three-phase A/D conversion module, audio A/D conversion module, FPGA module and DSP signal processing module. Sampling and FFT transformation determine whether the amplitude and frequency characteristic curve of the signal has a specific frequency within the preset threshold range, and automatically determines the validity of the signal.
It realizes the effectiveness of the directional signal automatically judges the directional signal, reduces the dependence on human judgment, improves efficiency and accuracy, and avoids waste of manpower and material resources.
Smart Images
Figure CN107948863B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of radio positioning and orientation instruments, and in particular relates to a directional audio signal detection device and method based on FFT. Background Art
[0002] The orienteering instrument is an important navigation device that can continuously track and orient the incoming radio wave signals. It is mainly used to receive vertical polarization signals in the VHF / UHF band and provide relevant azimuth information. Together with the integrated display device, it forms an automatic orientation system to achieve the orientation task of the orienteering instrument.
[0003] When the direction finder receives the radio frequency signal from the direction of the target transmitting source, it can accurately locate and output the digital direction signal to complete the positioning function of the direction finder. In the prior art, the pilot of the direction finder monitors the directional audio signal (5.68KHz) through headphones to determine whether the directional direction signal is valid at this time. When an obvious audio signal is monitored, it is determined to be a valid direction signal; when noise is monitored, it is determined to be an invalid direction signal. Therefore, when the prior art manually determines whether it is a valid direction signal, it requires the monitoring personnel to have a high level of technology and wastes manpower and material resources. Summary of the invention
[0004] In view of the above problems, the purpose of the present invention is to provide a directional audio signal detection device and method based on FFT, which can automatically determine whether the azimuth signal obtained by the direction finder is valid, and when the azimuth signal is invalid, the azimuth signal is not output.
[0005] In order to achieve the above object, the present invention adopts the following technical solution to achieve it.
[0006] Technical solution 1:
[0007] A directional audio signal detection device based on FFT, the directional audio signal detection device comprising: a directional antenna, a director and a display; the director comprises: a receiving unit and a control unit;
[0008] The RF output terminal of the directional antenna is connected to the RF input terminal of the receiving unit, the audio output terminal of the receiving unit is connected to the audio input terminal of the directional antenna and the audio input terminal of the control unit respectively, the azimuth signal output terminal of the directional antenna is connected to the azimuth signal input terminal of the control unit, and the data output terminal of the control unit is connected to the data input terminal of the display;
[0009] The control unit includes: a three-phase A / D conversion module, an audio A / D conversion module, an FPGA module and a DSP signal processing module connected in sequence, the signal input end of the three-phase A / D conversion module is connected to the audio input end of the directional antenna as the audio input end of the control unit, and the output end of the DSP signal processing module is connected to the data input end of the display as the data output end of the control unit.
[0010] The characteristics and further improvements of the technical solution 1 of the present invention are:
[0011] (1) The three-phase A / D conversion module is implemented using the SDC2904-2112-D chip.
[0012] (2) The audio A / D conversion module is implemented using the AD9780 chip.
[0013] (3) The FPGA module is implemented using the EP3C10F256 chip.
[0014] (4) The DSP signal processing module is implemented using the TMS320VC5509A chip.
[0015] (5) Setting the frequency of the directional audio signal to f;
[0016] The directional antenna is used to receive a radio frequency signal in space, modulate the radio frequency signal to obtain a radio frequency modulation signal, and send the radio frequency modulation signal to a receiving unit of the director, and there is a phase difference between the radio frequency modulation signal and the reference signal scanned by the antenna;
[0017] The receiving unit of the director is used to perform frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and send the audio signal with a direction to the control unit and the directional antenna respectively;
[0018] The directional antenna is further used to amplify, filter and phase-detect the directional audio signal in sequence to obtain an analog directional signal, and send the analog directional signal to the control unit of the director;
[0019] The control unit of the orienter is used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0020] The control unit of the director is also used to convert the directional audio signal into a directional digital audio signal, sample the directional digital audio signal to obtain sampling data, perform FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determine whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data; if so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.
[0021] (6) a three-phase A / D conversion module in the control unit, used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0022] The audio A / D conversion module in the control unit is used to convert the audio signal with orientation into a digital audio signal with orientation, and send the digital audio signal with orientation to the FPGA module;
[0023] The FPGA module in the control unit is used to sample the digital audio signal with orientation to obtain sampling data, and send the sampling data to the DSP signal processing module;
[0024] The DSP signal processing module in the control unit is used to perform FFT transformation on the sampled data to obtain an amplitude-frequency characteristic curve of the sampled data, and determine whether there is a frequency f within a preset amplitude threshold range based on the amplitude-frequency characteristic curve of the sampled data. If so, the transmission azimuth information of the radio frequency signal is output; otherwise, information that there is no valid target signal is output.
[0025] Technical solution 2:
[0026] A directional audio signal detection method based on FFT, the detection method is applied to the detection device as described in the technical solution 1, the directional audio signal detection method comprises: setting the frequency f of the directional audio signal;
[0027] The directional antenna receives a radio frequency signal in space, modulates the radio frequency signal to obtain a radio frequency modulation signal, and sends the radio frequency modulation signal to a receiving unit of the director, wherein there is a phase difference between the radio frequency modulation signal and a reference signal scanned by the antenna;
[0028] The receiving unit of the director performs frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and sends the audio signal with a direction to the control unit and the directional antenna respectively;
[0029] The directional antenna amplifies, filters and performs phase detection processing on the directional audio signal in sequence to obtain an analog directional signal, and sends the analog directional signal to the control unit of the director;
[0030] The control unit of the orienter converts the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0031] The control unit of the director converts the directional audio signal into a directional digital audio signal, samples the directional digital audio signal to obtain sampling data, performs FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determines whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data. If so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.
[0032] The directional audio signal detection method based on the FFT algorithm provided in the embodiment of the present invention can intuitively and effectively determine whether there is a valid azimuth signal. If there is a valid azimuth signal, the azimuth signal is displayed; otherwise, no valid azimuth signal is displayed; the method is intuitive and clear, and has strong objectivity. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0034] Figure 1 A schematic diagram of the structure of a directional audio signal detection device based on FFT provided by an embodiment of the present invention;
[0035] Figure 2 A schematic diagram of the structure of a control unit provided by an embodiment of the present invention;
[0036] Figure 3 A schematic diagram of a flow chart of a directional audio signal detection method based on FFT provided by an embodiment of the present invention;
[0037] Figure 4 Schematic diagram of the workflow of FFT-based directional audio signal detection software. DETAILED DESCRIPTION
[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.
[0039] The embodiment of the present invention provides a directional audio signal detection device based on FFT, such as Figure 1 As shown, the directional audio signal detection device includes: a directional antenna, a director and a display; the director includes: a receiving unit and a control unit;
[0040] The RF output terminal of the directional antenna is connected to the RF input terminal of the receiving unit, the audio output terminal of the receiving unit is connected to the audio input terminal of the directional antenna and the audio input terminal of the control unit respectively, the azimuth signal output terminal of the directional antenna is connected to the azimuth signal input terminal of the control unit, and the data output terminal of the control unit is connected to the data input terminal of the display;
[0041] Specifically, Figure 2 As shown, the control unit includes: a three-phase A / D conversion module, an audio A / D conversion module, an FPGA module and a DSP signal processing module connected in sequence, the signal input end of the three-phase A / D conversion module is connected to the audio input end of the directional antenna as the audio input end of the control unit, and the output end of the DSP signal processing module is connected to the data input end of the display as the data output end of the control unit.
[0042] Specifically, the three-phase A / D conversion module is implemented using the SDC2904-2112-D chip.
[0043] The audio A / D conversion module is implemented using the AD9780 chip.
[0044] The FPGA module is implemented using the EP3C10F256 chip.
[0045] The DSP signal processing module is implemented using the TMS320VC5509A chip.
[0046] Furthermore, the frequency of the directional audio signal is set to f, then:
[0047] The directional antenna is used to receive a radio frequency signal in space, modulate the radio frequency signal to obtain a radio frequency modulation signal, and send the radio frequency modulation signal to a receiving unit of the director, and there is a phase difference between the radio frequency modulation signal and the reference signal scanned by the antenna;
[0048] The receiving unit of the director is used to perform frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and send the audio signal with a direction to the control unit and the directional antenna respectively;
[0049] The directional antenna is further used to amplify, filter and phase-detect the directional audio signal in sequence to obtain an analog directional signal, and send the analog directional signal to the control unit of the director;
[0050] The control unit of the orienter is used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0051] The control unit of the director is also used to convert the directional audio signal into a directional digital audio signal, sample the directional digital audio signal to obtain sampling data, perform FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determine whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data; if so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.
[0052] Specifically,
[0053] The three-phase A / D conversion module in the control unit is used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0054] The audio A / D conversion module in the control unit is used to convert the audio signal with orientation into a digital audio signal with orientation, and send the digital audio signal with orientation to the FPGA module;
[0055] The FPGA module in the control unit is used to sample the digital audio signal with orientation to obtain sampling data, and send the sampling data to the DSP signal processing module;
[0056] The DSP signal processing module in the control unit is used to perform FFT transformation on the sampled data to obtain an amplitude-frequency characteristic curve of the sampled data, and determine whether there is a frequency f within a preset amplitude threshold range based on the amplitude-frequency characteristic curve of the sampled data. If so, the transmission azimuth information of the radio frequency signal is output; otherwise, information that there is no valid target signal is output.
[0057] The embodiment of the present invention further provides a directional audio signal detection method based on FFT, and the detection method is applied to the detection device of the above embodiment, such as Figure 3As shown, the directional audio signal detection method includes: setting the frequency f of the directional audio signal;
[0058] The directional antenna receives a radio frequency signal in space, modulates the radio frequency signal to obtain a radio frequency modulation signal, and sends the radio frequency modulation signal to a receiving unit of the director, wherein there is a phase difference between the radio frequency modulation signal and a reference signal scanned by the antenna;
[0059] The receiving unit of the director performs frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and sends the audio signal with a direction to the control unit and the directional antenna respectively;
[0060] The directional antenna amplifies, filters and performs phase detection processing on the directional audio signal in sequence to obtain an analog directional signal, and sends the analog directional signal to the control unit of the director;
[0061] The control unit of the orienter converts the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal;
[0062] The control unit of the director converts the directional audio signal into a directional digital audio signal, samples the directional digital audio signal to obtain sampling data, performs FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determines whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data. If so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.
[0063] For example, the software interrupts the sampling of the audio signal, calculates the frequency value and the average amplitude value of the signal using FFT, performs spectrum analysis, and detects peak values. Finally, the results are output. The workflow of the directional audio detection software is as follows: Figure 4 As shown. After the software completes the initialization work, it enters the state of continuously judging whether the signal exists. After completing a 512-point data storage, an interrupt signal is given, and then the data is read, FFT calculation, spectrum analysis, and peak detection are performed. Finally, the result is output. The software outputs the detection result through FFT calculation and takes 30 values continuously. When 20 of the values are valid, it is judged that there is a valid audio signal and the digital azimuth signal is output normally; when the valid value is less than 20, it is judged that there is no valid audio signal, and the digital azimuth signal outputs an invalid azimuth. The directional audio signal detection method based on the FFT algorithm can intuitively and effectively judge whether there is a valid azimuth signal. When there is a valid azimuth signal, the azimuth signal is displayed; otherwise, it is displayed that there is no valid azimuth signal; it is intuitive and clear, and objective.
[0064] The direction finder receives radio wave signals for continuous tracking and orientation. It is mainly used to receive vertical polarization signals in the VHF / UHF band and provide relevant azimuth information. It forms an automatic orientation system together with the aircraft comprehensive display to achieve helicopter assisted homing and aircraft aerial refueling tasks. When a valid azimuth signal is detected, it is displayed to achieve assisted homing and other tasks. When no valid signal is detected, the azimuth signal is not displayed.
[0065] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above-mentioned method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above-mentioned method embodiment; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.
[0066] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A directional audio signal detection device based on FFT, characterized in that: The directional audio signal detection device comprises: a directional antenna, a director and a display; the director comprises: a receiving unit and a control unit; The RF output terminal of the directional antenna is connected to the RF input terminal of the receiving unit, the audio output terminal of the receiving unit is connected to the audio input terminal of the directional antenna and the audio input terminal of the control unit respectively, the azimuth signal output terminal of the directional antenna is connected to the azimuth signal input terminal of the control unit, and the data output terminal of the control unit is connected to the data input terminal of the display; The control unit comprises: a three-phase A / D conversion module, an audio A / D conversion module, an FPGA module and a DSP signal processing module connected in sequence, the signal input end of the three-phase A / D conversion module is connected to the audio input end of the directional antenna as the audio input end of the control unit, and the output end of the DSP signal processing module is connected to the data input end of the display as the data output end of the control unit; Set the frequency of the directional audio signal to f; The directional antenna is used to receive a radio frequency signal in space, modulate the radio frequency signal to obtain a radio frequency modulation signal, and send the radio frequency modulation signal to a receiving unit of the director, and there is a phase difference between the radio frequency modulation signal and the reference signal scanned by the antenna; The receiving unit of the director is used to perform frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and send the audio signal with a direction to the control unit and the directional antenna respectively; The directional antenna is further used to amplify, filter and phase-detect the directional audio signal in sequence to obtain an analog directional signal, and send the analog directional signal to the control unit of the director; The control unit of the orienter is used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal; The control unit of the director is also used to convert the directional audio signal into a directional digital audio signal, sample the directional digital audio signal to obtain sampling data, perform FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determine whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data; if so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.
2. The FFT-based directional audio signal detection device according to claim 1, characterized in that: The three-phase A / D conversion module is implemented using the SDC2904-2112-D chip.
3. The FFT-based directional audio signal detection device according to claim 1, characterized in that: The audio A / D conversion module is implemented using the AD9780 chip.
4. The FFT-based directional audio signal detection device according to claim 1, characterized in that: The FPGA module is implemented using the EP3C10F256 chip.
5. The FFT-based directional audio signal detection device according to claim 1, characterized in that: The DSP signal processing module is implemented using the TMS320VC5509A chip.
6. The FFT-based directional audio signal detection device according to claim 1, characterized in that: The three-phase A / D conversion module in the control unit is used to convert the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal; The audio A / D conversion module in the control unit is used to convert the audio signal with orientation into a digital audio signal with orientation, and send the digital audio signal with orientation to the FPGA module; The FPGA module in the control unit is used to sample the digital audio signal with orientation to obtain sampling data, and send the sampling data to the DSP signal processing module; The DSP signal processing module in the control unit is used to perform FFT transformation on the sampled data to obtain an amplitude-frequency characteristic curve of the sampled data, and determine whether there is a frequency f within a preset amplitude threshold range based on the amplitude-frequency characteristic curve of the sampled data. If so, the transmission azimuth information of the radio frequency signal is output; otherwise, information that there is no valid target signal is output.
7. A directional audio signal detection method based on FFT, the detection method being applied to the detection device as claimed in claim 1, characterized in that: The directional audio signal detection method comprises: setting a frequency f of the directional audio signal; The directional antenna receives a radio frequency signal in space, modulates the radio frequency signal to obtain a radio frequency modulation signal, and sends the radio frequency modulation signal to a receiving unit of the director, wherein there is a phase difference between the radio frequency modulation signal and a reference signal scanned by the antenna; The receiving unit of the director performs frequency selection, frequency conversion, amplification and detection processing on the radio frequency modulated signal in sequence to obtain an audio signal with a direction, and sends the audio signal with a direction to the control unit and the directional antenna respectively; The directional antenna amplifies, filters and performs phase detection processing on the directional audio signal in sequence to obtain an analog directional signal, and sends the analog directional signal to the control unit of the director; The control unit of the orienter converts the analog azimuth signal into a digital azimuth signal to obtain the transmission azimuth information of the radio frequency signal; The control unit of the director converts the directional audio signal into a directional digital audio signal, samples the directional digital audio signal to obtain sampling data, performs FFT transformation on the sampling data to obtain an amplitude-frequency characteristic curve of the sampling data, and determines whether there is a frequency f within a preset amplitude threshold range according to the amplitude-frequency characteristic curve of the sampling data. If so, the control unit outputs the transmission directional information of the radio frequency signal; otherwise, the control unit outputs information that there is no valid target signal.