Rotor noise filtering device for digital interphone system of helicopter

Abstract

The utility model provides a rotor noise filtering device for a digital interphone system of a helicopter. The rotor noise filtering device comprises a filter main body; the filter main body comprises a noise reduction equipment main body, a voice acquisition filter circuit equipment main body and an amplification circuit equipment main body. The utility model provides a rotor noise filtering device for a communication system in a digital machine of a helicopter, and the device carries out the preliminary filtering of a part of engine noise and rotor noise which are collected by a microphone and appear in the flight process of the helicopter through a noise reduction module of an internal operation spectral subtraction method, an MMSE algorithm, a Wiener filtering algorithm and a VAD algorithm. And a comb-shaped filtering algorithm which is operated in the ARM processor and aims at a specific model is used, so that the defects of a single filtering algorithm are comprehensively overcome, the problem of whistling caused by the fact that part of rotor noise still leaks into the earphone after noise reduction is solved, the voice quality is improved, the voice state is clear and no whistling is caused when the whole machine is in a flying state, and the safety of the whole machine is ensured. And the effects of suppressing whistling and comb-shaped filtering are achieved.

Description

Technical Field

[0001] This utility model relates to the field of voice processing technology, and in particular to a rotor noise filtering device for a helicopter digital in-flight communication system. Background Technology

[0002] In the aircraft's voice circuit, the noise reduction module's acquisition circuit has a limited requirement for the voice volume. To avoid clipping distortion caused by the input voice exceeding the range, the voice volume input to the noise reduction circuit is limited to 90mV. At this time, the noise reduction circuit can eliminate most of the noise by running spectral subtraction, MMSE algorithm, Wiener filtering algorithm, and VAD algorithm. At this time, the output signal of the noise reduction module is 110mV.

[0003] Measurements of the noise-reduced voice revealed that noise at 14 frequency points, including 1167Hz, 1772Hz, 1270Hz, 1375Hz, 1700Hz, 1900Hz, 2260Hz, 2550Hz, 2924Hz, 3410Hz, 3600Hz, 3600Hz, 3850Hz, and 4406Hz, could not be completely filtered out. The output voice from the noise reduction module on the aircraft's voice circuit was relatively unclear, and the volume of the voice decreased to some extent after processing by the noise reduction module.

[0004] Therefore, it is necessary to provide a rotor noise filtering device for a helicopter digital intercom system to solve the above-mentioned technical problems. Utility Model Content

[0005] This invention provides a rotor noise filtering device for a helicopter digital in-flight communication system, which solves the problem that the output voice of the noise reduction module in the aircraft voice circuit is not clear and the voice volume will decrease to a certain extent after the noise reduction module processes it.

[0006] To solve the above-mentioned technical problems, this utility model provides a rotor noise filtering device for a helicopter digital intercom system, comprising:

[0007] The filter body includes a noise reduction device body, a voice acquisition and filtering circuit device body, and an amplification circuit device body.

[0008] The main body of the noise reduction device includes a microphone input circuit, an operational amplifier circuit, an AD / DA circuit, a DSP processor, and an output circuit.

[0009] Preferably, the main body of the voice acquisition and filtering circuit device includes a 1D2 voice acquisition chip TLV320AIC3106, a 1D3 ARM processor STM32F429ZIT6, and two coupling capacitors 1C1 and 1C2.

[0010] Preferably, the main body of the amplifier circuit device consists of one operational amplifier circuit 1D4, five resistors R1 to R5, and three capacitors C1 to C3. This operational amplifier is a negative feedback operational amplifier, wherein R1, R4, and R5 provide the midpoint voltage used by the operational amplifier, C3 filters the midpoint voltage, and the ratio of R3 to R2 determines the amplification factor of this operational amplifier.

[0011] Preferably, C2 couples the output, isolates the output DC voltage, and C1, together with the operational amplifier, forms a filter circuit to filter out high-frequency signals above 50kHz.

[0012] Preferably, the surface of the filter body is provided with a wiring tube, and fixing blocks are fixedly installed on both sides of the surface of the filter column. A reciprocating screw is rotatably installed on one side of the surface of the fixing block, and an adjusting block is fixedly connected to one end of the reciprocating screw. A limit rod is fixedly installed on the other side of the surface of the fixing block.

[0013] Preferably, threaded blocks are threaded on both sides of the outer surface of the reciprocating lead screw, and a clamping plate is fixedly installed on one side of the threaded blocks.

[0014] Preferably, a buffer pad is fixedly connected to the surface of the clamping plate, and the buffer pad is made of rubber.

[0015] Compared with related technologies, the rotor noise filtering device for a helicopter digital intercom system provided by this utility model has the following beneficial effects:

[0016] This invention provides a rotor noise filtering device for a helicopter digital in-flight communication system. The device uses an internal noise reduction module employing spectral subtraction, MMSE, Wiener filtering, and VAD algorithms to initially filter out some engine and rotor noise generated during helicopter flight, collected by the microphone. A voice acquisition chip and an ARM processor then collect the remaining voice signal, which still contains some rotor noise after noise reduction. A comb filtering algorithm specific to the aircraft model, running within the ARM processor, performs a secondary filter on the rotor noise that was not initially filtered out. An operational amplifier circuit amplifies the filtered voice signal before sending it to the back-end circuitry. This high-quality filtering algorithm for helicopter rotor and engine noise comprehensively addresses the shortcomings of single filtering algorithms, resolving the issue of some rotor noise leaking into the headset after noise reduction, thus preventing howling. This improves voice quality and ensures clear, howling-free voice during flight, effectively suppressing howling and performing comb filtering. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the first embodiment of a rotor noise filtering device for a helicopter digital in-flight communication system provided by this utility model;

[0018] Figure 2 for Figure 1 The diagram shows the internal structure of the filter body.

[0019] Figure 3 for Figure 2 The diagram shows the main structure of the noise reduction device.

[0020] Figure 4 A schematic diagram of the voice acquisition and filtering function of a rotor noise filtering device for a helicopter digital in-flight communication system provided by this utility model;

[0021] Figure 5 Hardware circuit diagram of a noise filtering method for a rotor noise filtering device for a helicopter digital in-flight communication system provided by this utility model;

[0022] Figure 6 This is a schematic diagram of the second embodiment of a rotor noise filtering device for a helicopter digital intercom system provided by this utility model;

[0023] Figure 7 for Figure 6 The enlarged schematic diagram at point A is shown.

[0024] The following are the labels in the diagram: 1. Filter body, 2. Noise reduction device body, 3. Voice acquisition and filtering circuit body, 4. Amplifier circuit body, 5. MIC input circuit, 6. Operational amplifier circuit, 7. AD / DA circuit, 8. DSP processor, 9. Output circuit, 10. Connecting pipe, 11. Fixing block, 12. Reciprocating lead screw, 13. Adjusting block, 14. Threaded block, 15. Clamping plate, 16. Buffer pad, 17. Limiting rod. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] First Embodiment

[0027] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ,in, Figure 1 This is a schematic diagram of the first embodiment of a rotor noise filtering device for a helicopter digital in-flight communication system provided by this utility model; Figure 2 for Figure 1 The diagram shows the internal structure of the filter body. Figure 3 for Figure 2 The diagram shows the main structure of the noise reduction device. Figure 4 This utility model provides a block diagram illustrating the voice acquisition and filtering function principle of a rotor noise filtering device for a helicopter digital intercom system. The rotor noise filtering device for a helicopter digital intercom system includes:

[0028] Filter body 1; the filter body 1 includes a noise reduction device body 2, a voice acquisition and filtering circuit device body 3, and an amplification circuit device body 4;

[0029] The main body 2 of the noise reduction device includes a MIC input circuit 5, an operational amplifier circuit 6, an AD / DA circuit 7, a DSP processor 8, and an output circuit 9.

[0030] The main body 3 of the voice acquisition and filtering circuit device includes a 1D2 voice acquisition chip TLV320AIC3106, a 1D3 ARM processor STM32F429ZIT6, and two coupling capacitors 1C1 and 1C2.

[0031] The main body 4 of the amplifier circuit device consists of one operational amplifier circuit 1D4, five resistors R1 to R5, and three capacitors C1 to C3. This operational amplifier is a negative feedback operational amplifier. R1, R4, and R5 provide the midpoint voltage used by the operational amplifier, C3 filters the midpoint voltage, and the ratio of R3 to R2 determines the amplification factor of this operational amplifier.

[0032] The C2 couples the output and isolates the DC voltage output. C1, together with the operational amplifier, forms a filter circuit to filter out high-frequency signals above 50kHz.

[0033] After the voice signal with some noise filtered out is input, a comb filter for different models is used to filter out the remaining noise signal a second time.

[0034] The ARM processor communicates with the voice acquisition chip via an SPI bus, controlling the chip to acquire voice signals, which are denoted as X(n). Noise data is collected from the aircraft, and the frequencies to be filtered out throughout the flight are identified as follows: 1167Hz, 1772Hz, 1270Hz, 1375Hz, 1700Hz, 1900Hz, 2260Hz, 2550Hz, 2924Hz, 3410Hz, 3600Hz, 3600Hz, 3850Hz, and 4406Hz.

[0035] Based on the above frequency points, design a comb filter with a bandwidth of 10Hz and a maximum attenuation of 50dB. The filter design formula is as follows: .

[0036] The main body of the amplifier circuit device 4 consists of one operational amplifier circuit 1D4, five resistors R1 to R5, and three capacitors C1 to C3. This operational amplifier is a negative feedback operational amplifier. R1, R4, and R5 provide the midpoint voltage used by the operational amplifier. C3 filters the midpoint voltage. The ratio of R3 to R2 determines the amplification factor of this operational amplifier. C2 couples the output and isolates the DC voltage of the output. C1 and the operational amplifier form a filter circuit to filter out high-frequency signals above 50kHz.

[0037] The working principle of the rotor noise filtering device for a helicopter digital intercom system provided by this utility model is as follows:

[0038] During operation, the noise reduction module, which uses internal spectral subtraction, MMSE, Wiener filtering, and VAD algorithms, first filters out some of the engine and rotor noise that occurs during helicopter flight, which is collected by the microphone. After the microphone is input, the noise signal is filtered out using spectral subtraction, MMSE, and Wiener filtering algorithms. Finally, the VAD algorithm is used to shut down the noise that cannot be completely filtered out.

[0039] The voice acquisition chip and ARM processor acquire the voice signal, which still contains some rotor noise after being processed by the noise reduction module. The comb filtering algorithm for specific models running inside the ARM processor is used to perform secondary filtering on the rotor noise that was not filtered out in the first stage. The filtered voice is amplified by the operational amplifier circuit and then sent to the back-end circuit.

[0040] Compared with related technologies, the rotor noise filtering device for a helicopter digital intercom system provided by this utility model has the following beneficial effects:

[0041] This invention provides a rotor noise filtering device for a helicopter digital in-flight communication system. The device uses an internal noise reduction module employing spectral subtraction, MMSE, Wiener filtering, and VAD algorithms to initially filter out some engine and rotor noise generated during helicopter flight, collected by the microphone. A voice acquisition chip and an ARM processor then collect the remaining voice signal, which still contains some rotor noise after noise reduction. A comb filtering algorithm specific to the aircraft model, running within the ARM processor, performs a secondary filter on the rotor noise that was not initially filtered out. An operational amplifier circuit amplifies the filtered voice signal before sending it to the back-end circuitry. This high-quality filtering algorithm for helicopter rotor and engine noise comprehensively addresses the shortcomings of single filtering algorithms, resolving the issue of some rotor noise leaking into the headset after noise reduction, thus preventing howling. This improves voice quality and ensures clear, howling-free voice during flight, effectively suppressing howling and performing comb filtering.

[0042] Second Embodiment

[0043] Please refer to the following: Figure 6 and Figure 7 Based on the rotor noise filtering device for a helicopter digital intercom system provided in the first embodiment of this application, the second embodiment of this application proposes another rotor noise filtering device for a helicopter digital intercom system. The second embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the second embodiment will not affect the separate implementation of the first embodiment.

[0044] Specifically, the second embodiment of this application provides a rotor noise filtering device for a helicopter digital intercom system, which differs in that the rotor noise filtering device for a helicopter digital intercom system has a wiring tube 10 on the surface of the filter body 1, and fixed blocks 11 are fixedly installed on both sides of the surface of the filter column 1. A reciprocating screw 12 is rotatably installed on one side of the surface of the fixed block 11, and an adjusting block is fixedly connected to one end of the reciprocating screw 12. A limit rod 17 is fixedly installed on the other side of the surface of the fixed block 11.

[0045] Both sides of the outer surface of the reciprocating lead screw 12 are threaded with threaded blocks 14, and a clamping plate 15 is fixedly installed on one side of the threaded block 14.

[0046] A buffer pad 16 is fixedly connected to the surface of the clamping plate 15, and the buffer pad 16 is made of rubber.

[0047] The working principle of the rotor noise filtering device for a helicopter digital intercom system provided by this utility model is as follows:

[0048] During operation, the reciprocating screw 12 is first rotated by rotating the adjusting block 13. The reciprocating screw 12 rotates and engages the two threaded blocks 14 on the outer surface of the threaded engagement, which move synchronously in opposite directions, thereby driving the two clamping plates 15 to clamp the connecting wire connected to the surface of the wiring conduit 10.

[0049] Compared with related technologies, the rotor noise filtering device for a helicopter digital intercom system provided by this utility model has the following beneficial effects:

[0050] This utility model provides a rotor noise filtering device for a helicopter digital in-flight communication system. By rotating the adjusting block 13, the reciprocating screw 12 is driven to rotate. The reciprocating screw 12 rotates and engages with two threaded blocks 14 on its outer surface, which move synchronously in opposite directions. This causes two clamping plates 15 to clamp the connecting wires connected to the surface of the connector 10. This device has a simple structure and is highly practical. When connecting external wires to the connector 10, the connection is restricted, maintaining the stability of the external wires during installation, preventing external forces from pulling out the wires, and improving the stability of the wire connection.

[0051] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A rotor noise filtering device for a helicopter digital intercom system, characterized in that, include: Filter body; The filter body includes a noise reduction device body, a voice acquisition and filtering circuit device body, and an amplification circuit device body; The main body of the noise reduction device includes a microphone input circuit, an operational amplifier circuit, an AD / DA circuit, a DSP processor, and an output circuit.

2. The rotor noise filtering device for a helicopter digital intercom system according to claim 1, characterized in that, The main body of the voice acquisition and filtering circuit device includes a 1D2 voice acquisition chip TLV320AIC3106, a 1D3 ARM processor STM32F429ZIT6, and two coupling capacitors 1C1 and 1C2.

3. The rotor noise filtering device for a helicopter digital intercom system according to claim 1, characterized in that, The main body of the amplifier circuit consists of one operational amplifier circuit 1D4, five resistors R1 to R5, and three capacitors C1 to C3. This operational amplifier is a negative feedback operational amplifier. R1, R4, and R5 provide the midpoint voltage used by the operational amplifier, C3 filters the midpoint voltage, and the ratio of R3 to R2 determines the amplification factor of this operational amplifier.

4. A rotor noise filtering device for a helicopter digital intercom system according to claim 3, characterized in that, The C2 couples the output and isolates the DC voltage output. C1, together with the operational amplifier, forms a filter circuit to filter out high-frequency signals above 50kHz.

5. A rotor noise filtering device for a helicopter digital intercom system according to claim 1, characterized in that, The filter body has a wiring tube on its surface. Fixing blocks are fixedly installed on both sides of the filter column surface. A reciprocating screw is rotatably installed on one side of the fixing block surface. An adjusting block is fixedly connected to one end of the reciprocating screw. A limit rod is fixedly installed on the other side of the fixing block surface.

6. A rotor noise filtering device for a helicopter digital intercom system according to claim 5, characterized in that, Both sides of the outer surface of the reciprocating lead screw are threaded with threaded blocks, and a clamping plate is fixedly installed on one side of the threaded blocks.

7. A rotor noise filtering device for a helicopter digital intercom system according to claim 6, characterized in that, A buffer pad made of rubber is fixedly connected to the surface of the clamping plate.

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