Multi-channel pulse frequency modulation signal acquisition card and device
By designing a multi-channel pulse frequency modulated signal acquisition card, the PDM signal output by the digital microphone is converted into a PCM signal using the FPGA device, and transmitted to the computer device through the USB control chip, the problem of difficulty in collecting and processing of digital microphone data is solved, and the problem of realizing the Efficient and convenient collection and processing effects.
Patent Information
- Application Number
- CN202421117691.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-05-21
AI Technical Summary
Digital microphone data collection and processing is difficult, and the development cost is high, which cannot meet the simple and efficient collection needs.
Provide a multi-channel pulse frequency modulation signal acquisition card, which adopts circuit board, 50-channel FPC interface, FPGA device, USB control chip and power module, and receives the PDM signal output from the digital microphone through the FPGA device and converts it into PCM signal. USB control chip Transmit PCM signals to computer equipment.
It realizes simple and efficient acquisition and processing of multi-channel digital microphone signals, reduces the cost of hardware system research and development and the difficulty of using digital microphones, provides parameter configuration functions, has a wider range of applications and a more powerful system functions.
Smart Images
Figure CN222441836U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of audio signal acquisition and processing, in particular to a multi-channel pulse frequency modulation signal acquisition card and equipment. Background Art
[0002] Microphone array technology is a multi-channel audio signal acquisition and processing technology. Specifically, microphone array technology can use an acoustic array device to determine the location of the sound source based on the phase difference between multiple audio signals and suppress noise from irrelevant directions. Microphone array technology has a wide range of application scenarios, such as abnormal fault detection in industry, bullet positioning, indoor sound source positioning, and smart speakers.
[0003] With the development of microphone array technology, digital microphones (hereinafter referred to as digital microphones) are gradually used as sound sensors in sound array devices. Compared with traditional analog microphones, digital microphones have the advantages of small size, high signal-to-noise ratio, wide signal bandwidth, and good signal consistency. However, in the sound array device using analog microphones, the microphone is connected to an analog-to-digital conversion (AD) acquisition card to sample and quantize the sound signal into a pulse code modulation (PCM) signal for processing by the computer system. The digital microphone outputs a pulse density modulation (PDM) signal. When collecting audio signals, the sound array device using digital microphones needs to convert the PDM signal into a PCM signal before it can be connected to the computer system. The conversion of PDM signals to PCM signals requires the design of a dedicated digital filter circuit, such as a PDM to PCM chip or a dedicated signal conversion circuit.
[0004] At present, the number of input channels that PDM to PCM chips can provide is limited, which is suitable for arrays with a small number of elements. A single chip cannot meet the requirements of a larger number of sound array channels (for example: 64-128 channels). At the same time, the PDM to PCM chip cannot configure filter-related parameters and cannot meet the needs of actual applications in some usage scenarios. The design cycle of designing a dedicated signal conversion circuit is long, the design cost is high, and the design difficulty is great. This makes digital microphone data collection and processing difficult, the development cost is high, and it cannot meet the needs of simple and efficient collection. Utility Model Content
[0005] The technical problem to be solved by the utility model is that the data collection and processing of digital microphones are difficult, the development cost is high, and the demand for simple and efficient collection cannot be met.
[0006] In order to solve the above technical problems, the utility model provides a multi-channel pulse frequency modulation signal acquisition card and equipment. The specific technical solutions are as follows:
[0007] In the first aspect, the utility model provides a multi-channel pulse frequency modulation signal acquisition card, including: a circuit substrate, and multiple 50-way FPC interfaces, FPGA devices, USB control chips and power modules arranged on the circuit substrate. Among them, multiple 50-way FPC interfaces are connected to the FPGA device, the FPGA device is connected to the USB control chip, and the FPGA device and the USB control chip are respectively connected to the power module. Multiple 50-way FPC interfaces are used to connect and drive multiple digital microphones; the FPGA device is used to receive PDM signals output by multiple digital microphones and convert the PDM signals into PCM signals; the USB control chip is used to transmit PCM signals to computer equipment, and the power module is used to supply power to the FPGA device and the USB control chip.
[0008] This multi-channel pulse frequency modulation signal acquisition card can collect PDM signals from multiple digital microphones through multiple 50-channel FPC interfaces and FPGA devices, and convert PDM signals into PCM signals. It is simple to operate and easy to use, and can save the R&D cost of the hardware system in the audio acquisition system and the difficulty of using digital microphones. At the same time, the FPGA device provides a parameter configuration function, and the conversion parameters of the FPGA device can be configured according to the user's usage requirements. It has a wider range of applications, more flexible operability, and more powerful system functions, thereby improving the convenience of digital microphone data acquisition and processing to meet the user's acquisition needs.
[0009] In combination with the first aspect, in an optional implementation, the 50-way FPC interface includes: 1-way power output interface, 8-way synchronous clock signal output interfaces and 32-way signal input interfaces. The power output interface is used to supply power to multiple digital microphones, the synchronous clock signal output interface is used to output synchronous clock signals to multiple digital microphones, and the signal input interface is used to receive output signals of multiple digital microphones.
[0010] In combination with the first aspect, in an optional implementation, the FPGA device includes: a hardware driver module, a signal processing module and a communication module, wherein the hardware driver module is connected to the signal processing module, and the signal processing module is connected to the communication module. The hardware driver module is used to drive a multi-channel digital microphone and convert the output signal into a PDM signal; the signal processing module is used to convert the PDM signal into a PCM signal; and the communication module is used to transmit the PCM signal to the USB control chip.
[0011] In combination with the first aspect, in an optional implementation, the hardware driver module includes: a clock unit and multiple input signal processing units. The clock unit is used to output a synchronous clock signal to the synchronous clock signal output interface; the input signal processing unit is used to convert the output signal into a PDM signal, the output signal is a dual-channel signal, and the PDM signal is a monophonic signal.
[0012] In combination with the first aspect, in an optional implementation, the signal processing module includes: multiple CIC extraction filters, FIR compensation filters and parameter configuration units. Among them, the CIC extraction filter is used to receive the PDM signal transmitted by the input signal processing unit, and downsample and filter the PDM signal, convert the PDM signal into a PCM filter signal and output it; the FIR compensation filter is used to compensate and filter the PCM filter signal output by the CIC extraction filter, obtain and output the PCM signal; the parameter configuration unit is used to configure multiple CIC extraction filters and FIR compensation filters according to the configuration parameters.
[0013] In combination with the first aspect, in an optional implementation, the communication module includes: a data receiving unit and a data sending unit. The data receiving unit is used to receive a data message sent by the USB control chip, parse the data message to obtain configuration parameters, and send the configuration parameters to the parameter configuration unit; the data sending unit is used to transmit the PCM signal output by the FIR compensation filter to the USB control chip.
[0014] In combination with the first aspect, in an optional implementation, the number of the 50-channel FPC interfaces is two, and the number of the CIC decimation filters is 128.
[0015] In combination with the first aspect, in an optional implementation, the CIC decimation filter is used to output a 32-bit PCM filter signal, the order of the CIC decimation filter ranges from 3 to 5, and the decimation multiple of the CIC decimation filter ranges from 8 to 32 times.
[0016] In combination with the first aspect, in an optional implementation, the USB control chip is a USB 3.0 chip.
[0017] In a second aspect, the utility model provides a multi-channel pulse frequency modulation signal acquisition device, including: a multi-channel pulse frequency modulation signal acquisition card as in the above-mentioned first aspect and any optional implementation thereof. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a schematic diagram of the structure of the multi-channel pulse frequency modulation signal acquisition card provided by the utility model;
[0019] Figure 2A schematic diagram of the structure of the FPGA device provided by the utility model;
[0020] Figure 3 This is a structural diagram of the data configuration message format provided by the utility model.
[0021] In the accompanying drawings, the components represented by the reference numerals are listed as follows:
[0022] 100. Circuit substrate; 200. 50-way FPC interface; 300. FPGA device; 310. Hardware driver module; 311. Clock unit; 312. Input signal processing unit; 320. Signal processing module; 321. CIC extraction filter; 322. FI R compensation filter; 323. Parameter configuration unit; 330. Communication module; 331. Data receiving unit; 332. Data sending unit; 400. USB control chip; 500. Power supply module. DETAILED DESCRIPTION
[0023] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.
[0024] Microphone array technology is a multi-channel audio signal acquisition and processing technology. Specifically, microphone array technology can use an acoustic array device to determine the location of the sound source based on the phase difference between multiple audio signals and suppress noise from irrelevant directions. Microphone array technology has a wide range of application scenarios, such as abnormal fault detection in industry, bullet positioning, indoor sound source positioning, and smart speakers.
[0025] With the development of microphone array technology, digital microphones (hereinafter referred to as digital microphones) are gradually used as sound sensors in sound array devices. Compared with traditional analog microphones, digital microphones have the advantages of small size, high signal-to-noise ratio, wide signal bandwidth, and good signal consistency. However, in the sound array device using analog microphones, the microphone is connected to an analog-to-digital conversion (AD) acquisition card to sample and quantize the sound signal into a pulse code modulation (PCM) signal for processing by the computer system. The digital microphone outputs a pulse density modulation (PDM) signal. When collecting audio signals, the sound array device using digital microphones needs to convert the PDM signal into a PCM signal before it can be connected to the computer system. The conversion of PDM signals to PCM signals requires the design of a dedicated digital filter circuit, such as a PDM to PCM chip or a dedicated signal conversion circuit.
[0026] At present, the number of input channels that PDM to PCM chips can provide is limited, which is suitable for arrays with a small number of elements. A single chip cannot meet the requirements of a larger number of sound array channels (for example: 64-128 channels). At the same time, the PDM to PCM chip cannot configure filter-related parameters and cannot meet the needs of actual applications in some usage scenarios. The design cycle of designing a dedicated signal conversion circuit is long, the design cost is high, and the design difficulty is great. This makes digital microphone data collection and processing difficult, the development cost is high, and it cannot meet the needs of simple and efficient collection.
[0027] In order to solve the problem that the data collection and processing of digital microphones are difficult, the development cost is high, and the demand for simple and efficient collection cannot be met. The embodiment of the utility model provides a multi-channel pulse frequency modulation signal acquisition card and equipment, wherein the acquisition card includes: a circuit substrate, and multiple 50-way FPC interfaces, FPGA devices, USB control chips and power modules arranged on the circuit substrate. Through multiple 50-way FPC interfaces and FPGA devices, multi-channel digital microphone signals can be collected and converted (for example: PDM signals are converted to PCM signals). The operation is simple and easy to use, which can save the R&D cost of the hardware system in the audio collection system and the difficulty of using digital microphones. At the same time, the FPGA device provides a parameter configuration function, and the conversion parameters of the FPGA device can be configured according to the user's usage requirements. The scope of application is wider, the operability is more flexible, and the system function is more powerful, thereby improving the convenience of digital microphone data collection and processing and meeting the collection requirements.
[0028] The solution provided by the embodiment of the utility model is introduced below in conjunction with the accompanying drawings.
[0029] Figure 1 The schematic diagram of the structure of the multi-channel pulse frequency modulation signal acquisition card provided by the utility model is as follows: Figure 1 As shown, an embodiment of the utility model provides a multi-channel pulse frequency modulation signal acquisition card, including: a circuit substrate 100, and a plurality of 50-way flexible printed circuit board (flexible printed circuit, FPC) interfaces 200, a field programmable gate array (FPGA) device 300, a universal serial bus (USB) control chip 400 and a power module 500 arranged on the circuit substrate 100.
[0030] Among them, a plurality of 50-way FPC interfaces 200 are connected to the FPGA device 300 , the FPGA device 300 is connected to the USB control chip 400 , and the FPGA device 300 and the USB control chip 400 are connected to the power module 500 respectively.
[0031] The multiple 50-way FPC interfaces 200 are used to connect and drive multiple digital microphones; the FPGA device 300 is used to receive PDM signals output by the multiple digital microphones and convert the PDM signals into PCM signals; the USB control chip 400 is used to transmit the PCM signals to the computer device, and the power module 500 is used to supply power to the FPGA device 300 and the USB control chip 400. In some embodiments, the input voltage of the power module 500 can be 5V-5.5V.
[0032] The multi-channel pulse frequency modulation signal acquisition card provided by the utility model can acquire the PDM signals of multiple digital microphones through multiple 50-channel FPC interfaces and FPGA devices, and convert the PDM signals into PCM signals. The operation is simple and convenient to use, which can save the R&D cost of the hardware system in the audio acquisition system and the difficulty of using digital microphones. At the same time, the FPGA device provides a parameter configuration function, and the conversion parameters of the FPGA device can be configured according to the user's usage requirements. The application range is wider, the operability is more flexible, and the system function is more powerful, thereby improving the convenience of digital microphone data acquisition and processing to meet the user's acquisition needs.
[0033] In some embodiments, the 50-way FPC interface 200 includes: 1-way power output interface, 8-way synchronous clock signal output interfaces and 32-way signal input interfaces. The power output interface is used to supply power to multiple digital microphones, the synchronous clock signal output interface is used to output synchronous clock signals to multiple digital microphones, and the signal input interface is used to receive output signals of multiple digital microphones.
[0034] In some embodiments, the multi-channel pulse frequency modulation signal acquisition card provided by the utility model may include two 50-way FPC interfaces. Each signal input interface can receive dual-channel signals generated by two digital microphones, and each 50-way FPC interface can connect 64 digital microphones. Taking two 50-way FPC interfaces as an example, the multi-channel pulse frequency modulation signal acquisition card provided by the utility model can connect 128 digital microphones. In this way, the multi-channel pulse frequency modulation signal acquisition card can meet the application requirements of collecting and processing data from multiple digital microphones.
[0035] In some embodiments, Figure 2 The schematic diagram of the structure of the FPGA device provided by the utility model is as follows: Figure 2 As shown, the FPGA device 300 includes: a hardware driver module 310 , a signal processing module 320 and a communication module 330 . The hardware driver module 310 is connected to the signal processing module 320 , and the signal processing module 320 is connected to the communication module 330 .
[0036] The hardware driver module 310 is used to drive the multi-channel digital microphones and convert the output signals into PDM signals; the signal processing module 320 is used to convert the PDM signals into PCM signals; and the communication module 330 is used to transmit the PCM signals to the USB control chip 400 .
[0037] In some embodiments, Figure 2 As shown, the hardware driver module 310 includes: a clock unit 311 and a plurality of input signal processing units 312. The clock unit 311 is used to output a synchronous clock signal to a synchronous clock signal output interface; and the input signal processing unit 312 is used to convert the output signal into a PDM signal.
[0038] In some embodiments, taking the multi-channel pulse frequency modulation signal acquisition card including two 50-way FPC interfaces as an example, the hardware driver module 310 may include: 64 input signal processing units 312. The 64 input signal processing units 312 may correspond one-to-one to the 64 signal input interfaces in the two 50-way FPC interfaces, that is, the 64 input signal processing units 312 may correspond one-to-one to the 64 digital microphones, and respectively process the output signals of the corresponding digital microphones.
[0039] In some embodiments, continuing to take the example of a multi-channel pulse frequency modulation signal acquisition card including two 50-way FPC interfaces, the clock unit 311 can generate a 4.8M clock, output 16-way synchronous clock signals to drive a digital microphone, and provide synchronous clock signals to 64 input signal processing units 312.
[0040] In some embodiments, the output signal is a dual-channel signal, and the PDM signal is a mono signal. Specifically, the input signal processing unit 312 receives a dual-channel microphone signal, and splits the dual-channel microphone signal into two mono microphone signals, whose signal format is a PDM signal.
[0041] In some embodiments, Figure 2 As shown, the signal processing module 320 includes: a plurality of cascaded integrator comb (CIC) decimation filters 321, a finite impulse response (FIR) compensation filter 322 and a parameter configuration unit 323.
[0042] The CIC decimation filter 321 is used to receive the PDM signal transmitted by the input signal processing unit 312, and downsample and filter the PDM signal, convert the PDM signal into a PCM filter signal and output it. The FIR compensation filter 322 is used to perform compensation filtering on the PCM filter signal output by the CIC decimation filter 321, obtain and output a PCM signal. The parameter configuration unit 323 is used to configure multiple CIC decimation filters 321 and FIR compensation filters 322 according to the configuration parameters.
[0043] In some embodiments, continuing to take the example of a multi-channel pulse frequency modulation signal acquisition card including two 50-way FPC interfaces, the number of CIC decimation filters 321 can be 128. The 128 CIC decimation filters 321 can output a 32-bit PCM filter signal, the order range of the CIC decimation filter 321 can be 3-5 orders, and the decimation multiple range of the CIC decimation filter 321 can be 8-32 times.
[0044] Furthermore, the FIR compensation filter 322 can use a multiplexing method to perform compensation filtering on the PCM filter signals output by the 128 CIC extraction filters 321, and output a 32-bit wide compensated PCM signal. In addition, the highest order of the FIR compensation filter 322 can be 32 orders, and the parameters of each order of the FIR compensation filter can be configured. In this way, the scope of application is wider, the operability is more flexible, and the needs of various different applications can be met.
[0045] In some embodiments, the FI R compensation filter 322 may again decimate the PCM filtered signal by a factor of 2.
[0046] In some embodiments, Figure 2 As shown, the communication module 330 includes: a data receiving unit 331 and a data sending unit 332 .
[0047] The data receiving unit 331 is used to receive the data message sent by the USB control chip 400, parse the data message to obtain the configuration parameters, and send the configuration parameters to the parameter configuration unit 323. The data sending unit 332 is used to transmit the PCM signal output by the FIR compensation filter 322 to the USB control chip 400, that is, to transmit the PCM signal to the USB control chip 400.
[0048] In some embodiments, the data sending unit 332 can correspond the PCM signal of the signal processing module 320 by channel and group and package the PCM signal. The data flow throughput of the signal processing module 320 can reach 150 MB per second.
[0049] In some embodiments, the data receiving unit 331 may receive a data message sent by the USB control chip 400, and the data message may be transmitted in a data configuration message format. Figure 3 The structure diagram of the data configuration message format provided by the utility model is as follows: Figure 3 As shown, the data message includes: a data message header, the order of the CIC decimation filter, the decimation multiple, the first order filter parameters, the second order filter parameters, ..., the 32nd order filter parameters. Further, the data receiving unit 331 parses the data message to obtain configuration parameters, and transmits the configuration parameters to the parameter configuration unit 323.
[0050] In some embodiments, the USB control chip 400 is a USB 3.0 chip, which can meet the application requirements of data transmission.
[0051] In some embodiments, continuing to take the multi-channel pulse frequency modulation signal acquisition card including two 50-way FPC interfaces as an example, the multi-channel pulse frequency modulation signal acquisition card provided by the utility model can connect 128 digital microphones. The computer device can send data packets through the USB control chip 400 to transfer configuration parameters. Then, the multi-channel pulse frequency modulation signal acquisition card configures the CIC extraction filter 321 and the FIR compensation filter 322 according to the configuration parameters and starts data collection. At the same time, the computer device receives data through the USB control chip 400 and the USB bus to complete data collection. Among them, the order of the CIC extraction filter 321 can be configured to be 5 orders, the extraction multiple is 8 times, and the actual sampling rate is 300KHz. At the same time, the FIR compensation filter 322 is configured as a 32-order low-pass filter with a passband range of 0-50KHz and a transition band of 10KHz.
[0052] In some embodiments, according to the needs of actual applications, the number of digital microphones connected to the multi-channel pulse frequency modulation signal acquisition card can also be any number less than or equal to 128 to meet the needs of multi-channel data acquisition, which is convenient and flexible to use. At the same time, the CIC extraction filter 321 can select 3, 4, and 5 orders, and the extraction multiple can be selected from 8 to 32 times. The parameters of each order of the FIR compensation filter 322 can also be modified to configure the passband and stopband width of the FIR compensation filter 322. In this way, the problem that the parameters in the hardware circuit of the PDM signal conversion PCM signal cannot be configured can be solved.
[0053] In some embodiments, the circuit system of the multi-channel pulse frequency modulation signal acquisition card provided by the present invention complies with the national standard for intrinsically safe circuits, and the protection level can be Ex IIB T4. In this way, the multi-channel pulse frequency modulation signal acquisition card provided by the present invention can be used in hazardous gas environments, thereby improving the safety and application scenarios of the multi-channel pulse frequency modulation signal acquisition card.
[0054] In some embodiments, the utility model also provides a multi-channel pulse frequency modulation signal acquisition device, including the multi-channel pulse frequency modulation signal acquisition card in the above embodiment. In this way, the multi-channel pulse frequency modulation signal acquisition device can collect PDM signals of multiple digital microphones through multiple 50-channel FPC interfaces and FPGA devices, and convert the PDM signals into PCM signals. It is simple to operate and easy to use, and can save the R&D cost of the hardware system in the audio acquisition system and the difficulty of using digital microphones. At the same time, the FPGA device provides a parameter configuration function, and the conversion parameters of the FPGA device can be configured according to the user's usage requirements. It has a wider range of applications, more flexible operability, and more powerful system functions, thereby improving the convenience of digital microphone data acquisition and processing to meet the user's acquisition needs.
[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0056] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0058] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.
Claims
1. A multi-channel pulse frequency modulation signal acquisition card, characterized in that: include: A circuit substrate, and a plurality of 50-way FPC interfaces, an FPGA device, a USB control chip and a power module arranged on the circuit substrate; Wherein, the multiple 50-way FPC interfaces are connected to the FPGA device, the FPGA device is connected to the USB control chip, and the FPGA device and the USB control chip are respectively connected to the power module; The multiple 50-channel FPC interfaces are used to connect and drive multiple digital microphones; the FPGA device is used to receive PDM signals output by the multiple digital microphones and convert the PDM signals into PCM signals; the USB control chip is used to transmit the PCM signals to a computer device, and the power module is used to supply power to the FPGA device and the USB control chip.
2. The multi-channel pulse frequency modulation signal acquisition card according to claim 1, characterized in that: The 50-way FPC interface includes: 1-way power output interface, 8-way synchronous clock signal output interfaces and 32-way signal input interfaces; The power output interface is used to supply power to the multi-channel digital microphones, the synchronous clock signal output interface is used to output synchronous clock signals to the multi-channel digital microphones, and the signal input interface is used to receive output signals of the multi-channel digital microphones.
3. The multi-channel pulse frequency modulation signal acquisition card according to claim 2, characterized in that: The FPGA device comprises: a hardware driving module, a signal processing module and a communication module, wherein the hardware driving module is connected to the signal processing module, and the signal processing module is connected to the communication module; Among them, the hardware driver module is used to drive the multi-channel digital microphone and convert the output signal into the PDM signal; the signal processing module is used to convert the PDM signal into the PCM signal; and the communication module is used to transmit the PCM signal to the USB control chip.
4. The multi-channel pulse frequency modulation signal acquisition card according to claim 3, characterized in that: The hardware driving module includes: a clock unit and a plurality of input signal processing units; Among them, the clock unit is used to output the synchronous clock signal to the synchronous clock signal output interface; the input signal processing unit is used to convert the output signal into the PDM signal, the output signal is a dual-channel signal, and the PDM signal is a mono signal.
5. The multi-channel pulse frequency modulation signal acquisition card according to claim 4, characterized in that: The signal processing module includes: a plurality of CIC extraction filters, a FIR compensation filter and a parameter configuration unit; Among them, the CIC extraction filter is used to receive the PDM signal transmitted by the input signal processing unit, and downsample and filter the PDM signal, convert the PDM signal into a PCM filter signal and output it; the FIR compensation filter is used to perform compensation filtering on the PCM filter signal output by the CIC extraction filter, obtain and output the PCM signal; the parameter configuration unit is used to configure the multiple CIC extraction filters and the FIR compensation filter according to the configuration parameters.
6. The multi-channel pulse frequency modulation signal acquisition card according to claim 5, characterized in that: The communication module includes: a data receiving unit and a data sending unit; Among them, the data receiving unit is used to receive the data message sent by the USB control chip, parse the data message to obtain the configuration parameters, and send the configuration parameters to the parameter configuration unit; the data sending unit is used to transmit the PCM signal output by the FIR compensation filter to the USB control chip.
7. The multi-channel pulse frequency modulation signal acquisition card according to claim 5, characterized in that: The number of the 50-channel FPC interfaces is two, and the number of the CIC decimation filters is 128.
8. The multi-channel pulse frequency modulation signal acquisition card according to claim 5, characterized in that: The CIC decimation filter is used to output a 32-bit PCM filter signal, the order of the CIC decimation filter ranges from 3 to 5, and the decimation multiple of the CIC decimation filter ranges from 8 to 32.
9. The multi-channel pulse frequency modulation signal acquisition card according to any one of claims 1 to 8, characterized in that: The USB control chip is a USB 3.0 chip.
10. A multi-channel pulse frequency modulation signal acquisition device, characterized in that: include: A multi-channel pulse frequency modulation signal acquisition card as described in any one of claims 1 to 9.