An audio capture card

Abstract

The utility model discloses an audio frequency acquisition card, including PCB circuit board, integrated with signal input module, AD conversion module, audio frequency processing module and FPC interface on it. Signal input module includes SCSI signal interface and optical fiber audio interface with analog and digital output end. AD conversion module connects the analog output end of SCSI interface through independent filter subcircuit, and converts analog signal into digital signal. Audio frequency processing module includes at least two audio interface chips, and is directly connected with the digital output end of optical fiber audio interface and SCSI interface respectively, and receives and decodes digital audio signal. FPC interface is used for gathering all digital audio signals and introducing external power supply. The utility model realizes analog audio, optical fiber digital audio and SCSI direct connection digital audio parallel acquisition and processing on a card, solves the problem of multi-device synchronization, and has the advantages of high integration, high sound quality and high reliability.

Description

Technical Field

[0001] This utility model relates to the field of audio signal processing technology, specifically to an audio acquisition card. Background Technology

[0002] In professional audio acquisition applications, it is often necessary to simultaneously input multiple types of audio signal sources, including analog and digital audio signals. However, existing audio acquisition devices are often limited in functionality, mostly supporting only analog input or digital input in specific formats, making it difficult to meet the acquisition needs of mixed signal sources. When users need to acquire analog and digital audio signals simultaneously, they usually need to configure multiple acquisition cards with different functions. This not only significantly increases system cost and connection complexity but also brings challenges to signal synchronization between multiple devices.

[0003] Furthermore, the ability of some high-performance audio devices (such as those equipped with SCSI signal interfaces) to simultaneously provide analog and digital audio output has not been fully utilized by existing acquisition cards, resulting in limitations on system integration and signal path flexibility. At the hardware design level, traditional acquisition cards also have shortcomings in power management, interference immunity, and circuit layout density, affecting audio quality and hindering product miniaturization and reliability improvements. Therefore, there is an urgent need for an audio acquisition card that is highly integrated, compatible with multiple signal types, and possesses excellent performance. Utility Model Content To address the shortcomings of existing technologies, this utility model aims to provide an audio acquisition card that can process analog audio signals, fiber optic digital audio signals, and SCSI direct-connect digital audio signals in parallel on a single card, supports multi-channel synchronous acquisition, and improves system integration, audio quality, and reliability through optimized circuit design and structural layout.

[0004] Technical solution of this utility model To achieve the above objectives, the present invention adopts the following technical solution: An audio capture card includes a PCB circuit board, characterized in that the PCB circuit board integrates: The signal input module includes a SCSI signal interface and an optical fiber audio interface, wherein the SCSI signal interface has an analog audio output terminal and a digital audio output terminal; The analog-to-digital conversion module includes at least one analog-to-digital conversion chip, the input of which is connected to the analog audio output of the SCSI signal interface through a filtering circuit, for converting analog audio signals into digital audio signals; The audio processing module includes at least two audio interface chips, wherein: The input terminal of the first audio interface chip is connected to the output terminal of the optical fiber audio interface; The input terminal of the second audio interface chip is connected to the digital audio output terminal of the SCSI signal interface; The FPC interface is connected to the output of the audio processing module and the output of the analog-to-digital converter module, respectively, for outputting the decoded audio signal and providing external power to the entire acquisition card. Preferably, the audio processing module includes multiple audio interface chips to form multiple independent audio processing channels.

[0005] Preferably, the analog-to-digital conversion module includes multiple analog-to-digital conversion chips to form multiple independent analog-to-digital conversion channels.

[0006] Preferably, the filtering circuit includes multiple independent filtering sub-circuits, the number of which corresponds to the number of analog signal input channels of the analog-to-digital converter chip, and the input terminal of each filtering sub-circuit is connected to the analog audio output terminal of the SCSI signal interface, and the output terminal is connected to the analog signal input terminal of the analog-to-digital converter chip.

[0007] Preferably, the filter sub-circuit includes a first resistor R1, a second resistor R2, a first capacitor C1, and a Schottky diode D1. One end of the first resistor R1 is connected to the output terminal of the SCSI signal interface; the other end of the first resistor R1 is connected together with one end of the second resistor R2, one end of the first capacitor C1, and the cathode of the Schottky diode D1; the other end of the second resistor R2 is grounded; the other end of the first capacitor C1 serves as an analog audio signal output terminal, used to connect to the analog signal input terminal of the analog-to-digital converter chip; and the anode of the Schottky diode D1 is grounded.

[0008] Preferably, the output of the optical fiber audio interface is connected to the input of the corresponding first audio interface chip via a coupling circuit; the coupling circuit includes a third resistor R3, a second capacitor C2, a fourth resistor R4, and a grounding resistor R5. Specifically, the VOUT pin output terminal of the optical fiber audio interface is connected to one end of the third resistor R3; the other end of the third resistor R3 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is simultaneously connected to one end of the fourth resistor R4 and one end of the grounding resistor R5; the other end of the fourth resistor R4 is connected to the input terminal of the first audio interface chip; and the other end of the grounding resistor R5 is grounded.

[0009] Preferably, the output control pin of the first audio interface chip and / or the second audio interface chip is connected to a switching circuit for controlling the output enable of the decoded digital audio signal; the switching circuit includes a transistor Q1; the output control pin of the audio interface chip is connected to the base of the transistor Q1 through a sixth resistor R6, the emitter of the transistor Q1 is grounded, and the collector is connected in series in the output path of the decoded digital audio signal, and the on / off state is output through the transistor's on / off control signal.

[0010] Preferably, the FPC interface includes multiple digital audio signal transmission pins, power supply pins, and control signal pins.

[0011] Preferably, the digital audio signal transmission pin is configured to transmit multiple digital audio signals from the analog-to-digital conversion module and the audio processing module.

[0012] Preferably, the power supply pin is used to introduce an external operating power supply.

[0013] Preferably, the control signal pins include an SCL pin and an SDA pin for the I²C communication protocol. Compared with the prior art, the beneficial effects of this utility model are: 1. Strong signal compatibility and high system integration: This invention integrates SCSI and fiber optic audio interfaces, and innovatively utilizes the analog and digital output characteristics of the SCSI signal interface to build a hybrid acquisition platform capable of parallel processing of analog signals, fiber optic digital signals, and SCSI direct-connect digital signals on a single card. This eliminates the need for users to configure multiple single-function acquisition cards to build a complete system, fundamentally solving the problem of mixed signal source access and significantly reducing system cost and complexity.

[0014] 2. Highly efficient multi-channel synchronous acquisition capability: By employing a parallel processing array composed of multiple analog-to-digital converter chips and audio interface chips, this invention achieves synchronous high-speed acquisition of multiple audio signals. This architecture not only breaks through the channel limit of a single chip but also completely avoids the inherent signal synchronization problem in traditional multi-card solutions, providing a reliable technical guarantee for high-quality audio production.

[0015] 3. Excellent audio quality and reliability: This invention features independent RC filtering and clamping protection circuits for each analog input channel, and employs a multi-layer PCB design with separate analog and digital grounds. These measures effectively suppress power supply noise, inter-signal interference, and transient overvoltage surges, ensuring high fidelity and high reliability in the acquisition process from a hardware perspective.

[0016] 4. Optimized power efficiency and structural design: By providing +5V and +3.3V power uniformly through the baseboard and FPC interface, this invention improves power processing efficiency and stability while reducing the number of external components. Combined with high-density PCB layout optimization, the board area is significantly reduced, achieving product miniaturization and optimized layout, making it particularly suitable for space-constrained embedded applications.

[0017] 5. Convenient Expansion and Secondary Development: The standardized FPC interface and modular functional design make it exceptionally easy to connect this acquisition card to external systems and expand its functionality. This design greatly reduces the complexity and time cost of secondary development for users, enhancing the product's engineering practicality and market adaptability. Attached Figure Description

[0018] Figure 1 This is a block diagram showing the overall module connection of the audio acquisition card of this utility model.

[0019] Figure 2 This is the circuit diagram of the filter sub-circuit in this utility model.

[0020] Figure 3 This is the circuit schematic diagram of the analog-to-digital converter chip in this utility model.

[0021] Figure 4 This is a circuit diagram of the connection circuit between the optical fiber audio interface and the first audio interface chip in this utility model.

[0022] Figure 5 This is a circuit diagram of the connection circuit between the SCSI signal interface and the second audio interface chip in this utility model.

[0023] Figure 6 This is a schematic diagram of the pin function definition of the FPC interface in an embodiment of this utility model. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 like Figure 1 As shown, this embodiment provides an audio acquisition card, the core of which is a multi-layer PCB circuit board. The board integrates a signal input module 1, an analog-to-digital conversion module 2, a filtering circuit 3, an audio processing module 4, and an FPC interface 5.

[0026] The signal input module 1 includes a SCSI signal interface 11 and an optical audio interface 12. The SCSI signal interface 11, as a high-performance interface, defines analog audio output and digital audio output, and can simultaneously acquire signals of two formats from the source device.

[0027] The analog-to-digital conversion module 2 includes multiple analog-to-digital conversion chips 21. In a preferred embodiment, the analog-to-digital conversion chips 21 are of the ADC-MS1808 type, and there are six of them, forming six independent analog-to-digital conversion channels. The analog signal input terminal of each analog-to-digital conversion chip 21 is connected to an analog audio output terminal of the SCSI signal interface 11 through an independent filter sub-circuit 31.

[0028] like Figure 2 As shown, the filter sub-circuit 31 is a specific RC filter and clamping circuit used to process one analog audio signal. Each analog-to-digital converter chip 21 needs to be connected to two of the filter sub-circuits 31, each processing the signal of one of its analog input channels. For example, for a stereo analog-to-digital converter chip, one filter sub-circuit processes the left channel signal, and the other processes the right channel signal.

[0029] Taking the filter sub-circuit of one channel as an example, it specifically includes a first resistor R1, a second resistor R2, a first capacitor C1, and a Schottky diode D1. One end of the first resistor R1 is connected to an analog audio output terminal (such as the left channel output) of the SCSI signal interface 11; the other end of the first resistor R1 is connected together with one end of the second resistor R2, one end of the first capacitor C1, and the cathode of the Schottky diode D1; the other end of the second resistor R2 is grounded; the other end of the first capacitor C1 serves as an analog audio signal output terminal, used to connect to an analog signal input terminal (such as the left channel input) of the analog-to-digital converter chip 21; the anode of the Schottky diode D1 is grounded.

[0030] like Figure 2 and Figure 3 As shown, in this circuit, the first resistor R1 and the first capacitor C1 together form an RC low-pass filter to filter out high-frequency noise; the second resistor R2 provides a discharge circuit for the first capacitor C1; the Schottky diode D1 uses its fast response and low on-state voltage drop characteristics to clamp the excessively high peak voltage of the input signal, effectively protecting the input pin of the sensitive analog-to-digital converter chip 21 in the subsequent stage.

[0031] Correspondingly, the filter sub-circuit connected to another channel of the same analog-to-digital converter chip has the exact same circuit structure and is used to process another signal (such as the right channel).

[0032] The audio processing module 4 includes multiple audio interface chips. In a preferred embodiment, such as... Figure 4 and Figure 5As shown, the audio interface chips are model MS8416T, and there are four of them. These four chips are divided into two groups to achieve specialized signal path processing: the input terminals of two of them (as the first audio interface chips 41a) are connected to the output terminal of the optical fiber audio interface 12 through the coupling circuit 121, and are specifically used to receive and decode digital audio signals from the fiber optic channel; the input terminals of the other two (as the second audio interface chips 41b) are directly connected to the digital audio output terminal of the SCSI signal interface 11, and are specifically used to receive and decode pure digital audio signals from the SCSI signal interface. This architecture clearly distinguishes digital signals from different sources, realizes parallel processing, and improves the system's data processing capability and reliability.

[0033] like Figure 4 As shown, in a preferred embodiment, the fiber optic audio interface 12 is a GQ-015 type fiber optic connector. Its output is connected to the input of the first audio interface chip 41a via a coupling circuit 121. The coupling circuit 121 includes a third resistor R3, a second capacitor C2, a fourth resistor R4, and a grounding resistor R5. Specifically, the VOUT pin output of the GQ-015 type fiber optic connector is connected to the third resistor R3; the other end of the third resistor R3 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is simultaneously connected to one end of the fourth resistor R4 and one end of the grounding resistor R5; the other end of the fourth resistor R4 is used to connect to the corresponding input of the first audio interface chip 41a; the other end of the grounding resistor R5 is grounded.

[0034] This network enables AC coupling (through capacitor C2), impedance matching (through resistors R3, R4, and R5), and DC bias, ensuring that the signal after photoelectric decoding can be transmitted to the subsequent audio interface chip with high quality and stability.

[0035] like Figure 4 As shown, each audio interface chip's output control pin is connected to an independent switching circuit 42, which is used to control the output enable of the digital audio signal after decoding by each chip.

[0036] The following description uses the switching circuit connected to the first audio interface chip 41a as an example. This switching circuit includes a transistor Q1 and a sixth resistor R6. The output control pin of the first audio interface chip 41a is connected to the base of the transistor Q1 through the sixth resistor R6. The emitter of the transistor Q1 is grounded, and the collector is connected in series in the output path of the decoded digital audio signal.

[0037] By controlling the level of the output control pins within the audio interface chip's internal logic, the conduction and cutoff of the corresponding transistors can be controlled, thereby achieving on / off control of the digital audio signal output for that channel. This design, which configures an independent switching circuit for each channel, greatly enhances the system's flexibility and reliability in signal routing and management.

[0038] The FPC interface 5 is a high-density FPC connector. In a preferred embodiment, the FPC interface 5 is an FPC0.5 2H-WS-60P model connector.

[0039] like Figure 6 As shown, its pinout includes a multi-channel digital audio signal transmission pin 51, a power supply pin 52, and a control signal pin 53. The digital audio signal transmission pin 51 is configured to transmit BCK, SDOUT, SCLK, and LRCLK signals from the analog-to-digital converter module 2, and SDOUT, RMCK, SCLK, and LRCLK signals from the audio processing module 4. The power supply pin 52 is used to draw +5V and 3.3V operating power from an external baseboard. The control signal pin 53 includes an SCL pin and an SDA pin for the I²C communication protocol, used for configuration communication with the main control device. Furthermore, each of the key high-speed signal pins in the digital audio signal transmission pin 51 has a corresponding GND grounding pin to form a complete signal return path, effectively ensuring signal integrity and reducing interference during transmission.

[0040] The PCB board adopts a multi-layer board design, and its layout is strictly divided into analog ground area and digital ground area. It is connected at a single point through a zero-ohm resistor (or ferrite bead) to effectively suppress the interference of digital signal on analog signal.

[0041] The PCB board employs a multi-layer design with separate analog and digital ground areas. Specifically, during PCB layout, the area containing the analog-to-digital conversion module 2 and the filter circuit 3 is designated as analog ground AGND, while the digital portion of the audio processing module 4 and the FPC interface 5 is designated as digital ground DGND. The analog and digital grounds are connected at a single point near the power input area of ​​the PCB via a ferrite bead or a zero-ohm resistor to form a unified reference ground potential. This design effectively blocks interference from digital circuit noise on sensitive analog signals, ensuring high signal-to-noise ratio and high fidelity in audio acquisition from a fundamental hardware perspective.

[0042] Working Principle: During operation, external analog audio signals are processed by various filter sub-circuits 31 after passing through the analog output terminal of the SCSI signal interface 11, and then sent to the corresponding analog-to-digital converter chip 21 to be converted into digital audio signals. External digital audio signals have two sources: one is input through the optical fiber audio interface 12; the other is direct input through the digital output terminal of the SCSI signal interface 11. All these digital signals are routed to different audio interface chips for reception and decoding. Finally, all processed digital audio signals, clock signals, and control signals are output to the external motherboard or processing system through the FPC interface 5, and the power required for the entire acquisition card is also introduced through this interface.

[0043] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. An audio acquisition card, comprising a PCB circuit board, characterized in that, The PCB circuit board integrates: The signal input module (1) includes a SCSI signal interface (11) and an optical fiber audio interface (12), wherein the SCSI signal interface (11) has an analog audio output terminal and a digital audio output terminal; The analog-to-digital conversion module (2) includes at least one analog-to-digital conversion chip (21), whose input terminal is connected to the analog audio output terminal of the SCSI signal interface (11) through a filter circuit (3) for converting analog audio signals into digital audio signals; The audio processing module (4) includes at least two audio interface chips, wherein: The input end of the first audio interface chip (41a) is connected to the output end of the optical fiber audio interface (12); The input terminal of the second audio interface chip (41b) is connected to the digital audio output terminal of the SCSI signal interface (11); The FPC interface (5) is connected to the output of the audio processing module (4) and the output of the analog-to-digital conversion module (2) respectively, and is used to output the decoded audio signal and introduce external power supply to the entire acquisition card.

2. An audio acquisition card according to claim 1, characterized in that, The analog-to-digital conversion module (2) includes multiple analog-to-digital conversion chips (21) to form multiple independent analog-to-digital conversion channels.

3. An audio acquisition card according to claim 1, characterized in that, The filtering circuit (3) includes multiple independent filtering sub-circuits (31). The number of filtering sub-circuits (31) corresponds to the number of analog signal input channels of the analog-to-digital converter chip (21). The input terminal of each filtering sub-circuit (31) is connected to the analog audio output terminal of the SCSI signal interface (11), and the output terminal is connected to the analog signal input terminal of the analog-to-digital converter chip (21).

4. An audio acquisition card according to claim 3, characterized in that, The filter sub-circuit (31) includes a first resistor R1, a second resistor R2, a first capacitor C1, and a Schottky diode D1. One end of the first resistor R1 is connected to the output terminal of the SCSI signal interface (11). The other end of the first resistor R1 is connected to one end of the second resistor R2, one end of the first capacitor C1, and the cathode of the Schottky diode D1. The other end of the second resistor R2 is grounded. The other end of the first capacitor C1 serves as an analog audio signal output terminal, used to connect to the analog signal input terminal of the analog-to-digital converter chip (21). The anode of the Schottky diode D1 is grounded.

5. An audio acquisition card according to claim 1, characterized in that, The output of the optical fiber audio interface (12) is connected to the input of the corresponding first audio interface chip (41a) through a coupling circuit (121); the coupling circuit (121) includes a third resistor R3, a second capacitor C2, a fourth resistor R4 and a grounding resistor R5; Wherein, the VOUT pin output terminal of the optical fiber audio interface (12) is connected to one end of the third resistor R3; the other end of the third resistor R3 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is simultaneously connected to one end of the fourth resistor R4 and one end of the grounding resistor R5; the other end of the fourth resistor R4 is connected to the input terminal of the first audio interface chip (41a); the other end of the grounding resistor R5 is grounded.

6. An audio acquisition card according to claim 1, characterized in that, The output control pins of the first audio interface chip (41a) and / or the second audio interface chip (41b) are connected to a switching circuit (42) for controlling the output enable of the decoded digital audio signal; the switching circuit (42) includes a transistor Q1; the output control pin of the audio interface chip is connected to the base of the transistor Q1 through a sixth resistor R6, the emitter of the transistor Q1 is grounded, and the collector is connected in series in the output path of the decoded digital audio signal, and the on / off control signal of the transistor is used to output the on / off state.

7. An audio acquisition card according to claim 1, characterized in that, The FPC interface (5) includes a multi-channel digital audio signal transmission pin (51), a power supply pin (52), and a control signal pin (53).

8. An audio acquisition card according to claim 7, characterized in that, The digital audio signal transmission pin (51) is configured to transmit multiple digital audio signals from the analog-to-digital conversion module (2) and the audio processing module (4).

9. An audio acquisition card according to claim 7, characterized in that, The power supply pin (52) is used to introduce an external operating power supply.

10. An audio acquisition card according to claim 7, characterized in that, The control signal pin (53) includes the SCL pin and the SDA pin for the I²C communication protocol.

Images