CN112822621A

CN112822621A - Test circuit and test method of dual-channel microphone and audio codec

Info

Publication number: CN112822621A
Application number: CN201911129915.1A
Authority: CN
Inventors: 叶宗立; 黄义政
Original assignee: Realtek Semiconductor Corp
Current assignee: Realtek Semiconductor Corp
Priority date: 2019-11-18
Filing date: 2019-11-18
Publication date: 2021-05-18
Anticipated expiration: 2039-11-18
Also published as: CN112822621B

Abstract

The invention discloses a test circuit and a test method of a dual-channel microphone and an audio codec, which are used for testing the dual-channel microphone comprising a first microphone and a second microphone. The first microphone outputs first data and the second microphone outputs second data. The test circuit comprises a comparison circuit, a counter and a decision circuit. The comparison circuit is used for comparing the first data with the second data and generating a comparison result. The counter is coupled to the comparison circuit and used for generating a count value according to the comparison result. The decision circuit is coupled to the counter and used for indicating whether the dual-channel microphone is faulty or not according to the count value and a threshold value.

Description

Test circuit and test method of dual-channel microphone and audio codec

Technical Field

The present invention relates to a dual-channel microphone, and more particularly, to a test circuit, a test method and an audio codec for a dual-channel microphone.

Background

Fig. 1 is a functional block diagram of a conventional two-channel microphone system. The binaural microphone system 100 comprises a binaural microphone 110 and an audio codec 120. The dual channel microphone 110 is soldered to a Printed Circuit Board (PCB), and includes a microphone 112 and a microphone 114. Microphones 112 and 114 may be microphones based on Micro Electro Mechanical System (MEMS) technology. The microphone 112 has a frequency pin cp1, a data output pin dp1 and a select pin SLC 1. The microphone 114 has a frequency pin cp2, a data output pin dp2 and a select pin SLC 2. The clock pin cp1 and the clock pin cp2 are electrically connected to the printed circuit board and receive the clock CLK from the audio codec 120. Microphone 112 and microphone 114 operate according to a frequency CLK. The data output pin dp1 and the data output pin dp2 are electrically connected on the printed circuit board. The microphone 112 outputs Pulse Density Modulation (PDM) data d1 of one bit through a data output pin dp1, and the microphone 114 outputs pulse density modulation data d2 of one bit through a data output pin dp 2. Data D is a combination of data D1 and data D2. The audio codec 120 provides the frequency CLK of the binaural microphone 110 through a frequency pin, and receives the data D (including the data D1 and the data D2) generated by the binaural microphone 110 through a data pin. After receiving the plurality of data D1 and the plurality of data D2, the audio codec 120 decodes or filters the data D1 and the data D2 to generate multi-bit Pulse-code modulation (PCM) data D _ PCM.

FIG. 2 shows the relationship between data D1, data D2, data D and clock CLK. Since the selection pin SLC1 is connected to the voltage source VDD and the selection pin SLC2 is grounded, when the clock CLK is at the high level (i.e., logic 1), the output data d1 of the microphone 112 has a value (i.e., the bit value1 shown in fig. 2, which may be bit 1 or 0), the output data d2 of the microphone 114 has a high impedance (i.e., Z shown in fig. 2), and when the clock CLK is at the low level (i.e., logic 0), the output data d1 of the microphone 112 has a high impedance, and the output data d2 of the microphone 114 has a value (i.e., the bit value2 shown in fig. 2, which may be bit 1 or 0). When the binaural microphone 110 normally operates, the content of the data D is an alternate arrangement of the bit values 1 and 2, which is equivalent to an alternate arrangement of the data D1 and D2.

Microphone 112 and microphone 114 may be soldered incorrectly. More specifically, the clock pin cp1, the data output pin dp1, the clock pin cp2 and the data output pin dp2 may float, which may result in a loss of communication or communication connection between the microphone 112 and/or the microphone 114 and the audio codec 120, i.e., a failure of the binaural microphone 110. However, the floating pin is not easily detected by human eyes, which causes difficulty in debugging the circuit.

Disclosure of Invention

In view of the foregoing, it is an object of the present invention to provide a testing circuit, a testing method and an audio codec for a binaural microphone.

The invention discloses a test circuit for testing a dual-channel microphone. The dual-channel microphone operates according to a frequency and includes a first microphone and a second microphone. The first microphone outputs first data through the first data output pin at a first level of the frequency, the second microphone outputs second data through the second data output pin at a second level of the frequency, and the first level is not equal to the second level. The first data output pin and the second data output pin are coupled with the capacitor. The test circuit comprises a comparison circuit, a counter and a decision circuit. The comparison circuit is used for comparing the first data with the second data and generating a comparison result. The counter is coupled to the comparison circuit and used for generating a count value according to the comparison result. The decision circuit is coupled to the counter and used for indicating whether the dual-channel microphone is faulty or not according to the count value and a threshold value.

The invention further discloses a testing method for testing the dual-channel microphone. The dual-channel microphone operates according to a frequency and includes a first microphone and a second microphone. The first microphone outputs first data through the first data output pin at a first level of the frequency, the second microphone outputs second data through the second data output pin at a second level of the frequency, and the first level is not equal to the second level. The first data output pin and the second data output pin are coupled with the capacitor. The test method comprises the following steps: (a) comparing the first data with the second data and generating a comparison result; (b) generating a count value according to the comparison result; and (c) indicating whether the dual-channel microphone is wrong or not according to the counting value and a threshold value.

The invention further discloses a testing method for testing the dual-channel microphone. The dual-channel microphone operates according to a frequency and includes a first microphone and a second microphone. The first microphone outputs a plurality of first data through the first data output pin at a first level of the frequency, the second microphone outputs a plurality of second data through the second data output pin at a second level of the frequency, and the first level is not equal to the second level. The first data output pin and the second data output pin are coupled with the capacitor. The test method comprises the following steps: (a) decoding or filtering the first data and the second data to generate first pulse code modulation data and second pulse code modulation data; (b) comparing the first pulse code modulation data with the second pulse code modulation data and generating a comparison result; (c) generating a count value according to the comparison result; and (d) indicating whether the two-channel microphone is wrong or not according to the counting value and a threshold value.

The invention further discloses an audio codec for testing a dual-channel microphone. The dual-channel microphone operates according to a frequency and includes a first microphone and a second microphone. The first microphone outputs a plurality of first data through the first data output pin at a first level of the frequency, the second microphone outputs a plurality of second data through the second data output pin at a second level of the frequency, and the first level is not equal to the second level. The first data output pin and the second data output pin are coupled with the capacitor. The audio codec includes a memory and a processor. The memory stores a plurality of program instructions or program codes. The processor is coupled to the memory and is configured to execute the program instructions or the program codes to perform the following operations: (a) decoding or filtering the first data and the second data to generate first pulse code modulation data and second pulse code modulation data; (b) comparing the first pulse code modulation data with the second pulse code modulation data and generating a comparison result; (c) generating a count value according to the comparison result; and (d) indicating whether the two-channel microphone is wrong or not according to the counting value and a threshold value.

The test circuit and the test method of the dual-channel microphone and the audio codec can quickly find whether the dual-channel microphone has errors. Compared with the prior art, the invention can accelerate the debugging process of the circuit.

The features, implementations and functions of the present invention will be described in detail with reference to the drawings.

Drawings

FIG. 1 is a functional block diagram of a conventional dual-channel microphone system;

FIG. 2 is a timing diagram of data D1, data D2, data D and clock CLK;

FIG. 3 is a functional block diagram of a binaural microphone system according to the present invention;

FIG. 4 is a functional block diagram of a test circuit according to an embodiment of the present invention;

FIG. 5 is a flow chart of an embodiment of the testing method of the present invention;

FIG. 6 shows an embodiment of the comparison circuit of FIG. 5;

FIG. 7 is a functional block diagram of a dual-channel microphone system according to another embodiment of the present invention; and

FIG. 8 is a flow chart of another embodiment of the testing method of the present invention.

Detailed Description

The technical terms of the following description refer to conventional terms in the technical field, and some terms are explained or defined in the specification, and the explanation of the some terms is based on the explanation or definition in the specification.

The disclosure includes a testing circuit, a testing method and an audio codec for a dual-channel microphone. Since some of the components included in the testing circuit and audio codec of the binaural microphone of the present invention may be known components alone, the following description will omit details of the known components without affecting the full disclosure and the feasibility of the device invention. In addition, part or all of the process of the testing method of the binaural microphone of the invention may be in the form of software and/or firmware, and may be executed by the testing circuit of the binaural microphone of the invention, the audio codec, or the equivalent thereof.

Fig. 3 is a functional block diagram of a binaural microphone system according to the present invention. The binaural microphone system 200 includes a binaural microphone 110 and an audio codec 220. The audio codec 220 may be a system on chip (SoC). The binaural microphone 110 and the audio codec 220 are soldered to a printed circuit board (not shown). The audio codec 220 samples the data D through its internal capacitor 225. The capacitor 225 has one end connected to ground and the other end coupled to one of the pins of the audio codec 220, through which the audio codec 220 receives the data D. The audio codec 220 may retrieve the data D1 and the data D2 from the data D according to the frequency CLK and the terminal voltage of the capacitor 225. The audio codec 220 decodes or filters the data D1 and the data D2 to generate a plurality of multi-bit pulse code modulation data D _ PCM.

When the microphone 112 and/or the microphone 114 are not properly soldered, the data D will appear to be specific. For example, when the clock pin cp1 or the data output pin dp1 is floating, the data d1 always presents a high impedance state, so that the terminal voltage of the capacitor 225 will not change (i.e., remain in the previous state) when the clock CLK is high. Thus, the content of the data D only includes the data D2, i.e., the audio codec 220 samples the data D2 at both the high level and the low level of the clock CLK. That is, when the binaural microphone 110 is not actually soldered to the pcb, the audio codec 220 samples two identical data frames within one cycle of the frequency CLK.

In one embodiment, the audio codec 220 has built-in test circuitry 230 to test the binaural microphone 110. FIG. 4 is a functional block diagram of a test circuit according to an embodiment of the present invention. FIG. 5 is a flowchart of an embodiment of a testing method of the present invention. Please refer to fig. 4 and fig. 5. The test circuit 230 includes a comparison circuit 410, a counter 420, and a decision circuit 430. The comparison circuit 410 compares the data d1 with the data d2 and generates a comparison result CR (step S510). The counter 420 generates a count value CV based on the comparison result CR (step S520). The decision circuit 430 indicates whether an error occurs in the binaural microphone 110 according to the count value CV and the threshold value Th (step S530). Details of each component and step are described below.

The comparison circuit 410 and step S510 can be implemented by logic gates. As shown in fig. 6, the logic gate 500 includes two inputs and one output. The two inputs of the logic gate 500 respectively receive the data d1 and the data d2, and the output thereof outputs the comparison result CR. In embodiment (a), when data d1 is equal to data d2, logic gate 500 outputs logic 1, and when data d1 is not equal to data d2, logic gate 500 outputs logic 0; for example, the logic gate 500 may be an exclusive-or (XNOR gate). In embodiment (B), when data d1 is not equal to data d2, logic gate 500 outputs logic 1, and when data d1 is equal to data d2, logic gate 500 outputs logic 0; for example, the logic gate 500 may be an exclusive OR gate (XOR gate).

Step S520 includes sub-steps S522, S524, and S526. In the embodiment (a), when the comparison result CR is equal to 1 (yes at step S522), the counter 420 increments the counter value CV (step S524), and when the comparison result CR is equal to 0 (no at step S522), the counter 420 resets the counter value CV (i.e., returns the counter value CV to zero) (step S526). In the embodiment (B), when the comparison result CR is equal to 1 (no at step S522), the counter 420 resets the counter value CV (step S526), and when the comparison result CR is equal to 0 (yes at step S522), the counter 420 increments the counter value CV (step S524).

Step S530 includes sub-steps S532, S534, and S536. In sub-step S532, the decision circuit 430 compares the counter value CV with a threshold Th. In either embodiment (a) or (B), when the count value CV is greater than the threshold Th (yes in step S532), the decision circuit 430 sets the flag FG to a first logic value (e.g., logic 1) to indicate that an error occurs in the binaural microphone (step S534); when the count value CV is not greater than the threshold Th (no at step S532), the decision circuit 430 sets the flag FG to a second logic value (e.g., logic 0) to indicate that the binaural microphone is not erroneous (step S536). The first logical value is not equal to the second logical value. In some embodiments, decision circuit 430 may be implemented with a comparator. The threshold Th may be empirically set, for example, several hundreds or thousands.

In summary, the test circuit 230 and the corresponding test method can indicate the abnormality of the binaural microphone 110 (e.g., the floating of the data output pin and/or the frequency pin of the microphone 112 and/or the microphone 114), which is helpful for the circuit designer to find the error early.

Referring to fig. 7, fig. 7 is a functional block diagram of a binaural microphone system according to another embodiment of the invention. The binaural microphone system 700 includes a binaural microphone 110 and an audio codec 720. The audio codec 720 includes a capacitor 725, a processor 740, and a memory 750. The audio codec 720 may be a system-on-a-chip. The binaural microphone 110 and the audio codec 720 are soldered to a printed circuit board (not shown). The audio codec 720 samples the data D through a capacitor 725. The capacitor 725 has one end connected to ground and the other end coupled to one of the pins of the audio codec 720, through which the audio codec 720 receives the data D. The audio codec 720 may fetch the data D1 and the data D2 from the data D according to the frequency CLK and the terminal voltage of the capacitor 725. The audio codec 720 decodes or filters the data D1 and the data D2 to generate a plurality of multi-bit pulse code modulation data D _ PCM.

The processor 740 can be a circuit or an electronic component with program execution capability, such as a central processing unit, a microprocessor, a micro-processing unit or an application-specific integrated circuit (ASIC), which processes the data d1 and the data d2 by executing a plurality of program codes or program instructions stored in the memory 750. The application specific integrated circuit may be, for example, a Digital Signal Processor (DSP). In the embodiment of fig. 7, the binaural microphone 110 is tested by the processor 740 executing software and/or firmware (i.e., executing program code or program instructions in the memory 750).

FIG. 8 is a flowchart of another embodiment of the testing method of the present invention. The method of fig. 8 is performed by the audio codec 720 and the processor 740.

Initially, the processor 740 decodes or filters the plurality of data D1 and the plurality of data D2 to generate the pulse code modulation data D _ PCM1 and the pulse code modulation data D _ PCM2 (step S810). The audio codec 720 outputs the pulse code modulation data D _ PCM1 and the pulse code modulation data D _ PCM2 simultaneously or alternately, in other words, the pulse code modulation data D _ PCM includes pulse code modulation data D _ PCM1 and pulse code modulation data D _ PCM 2. The pulse code modulation data D _ PCM1 corresponds to one channel of the binaural microphone 110, and the pulse code modulation data D _ PCM2 corresponds to the other channel of the binaural microphone 110. When the data output pin and/or the frequency pin of the microphone 112 and/or the microphone 114 are floating, the PCM data D _ PCM1 is equal to the PCM data D _ PCM 2. Step S810 is well known to those skilled in the art, and therefore will not be described herein.

Next, the processor 740 compares the pulse code modulation data D _ PCM1 with the pulse code modulation data D _ PCM2 and generates a comparison result CR (step S820), generates a counter value CV according to the comparison result CR (step S830), and then indicates whether an error has occurred in the binaural microphone 110 according to the counter value CV and the threshold Th (step S840). Steps S820, S830 and S840 are similar to steps S510, S520 and S530, respectively, and thus are not repeated.

Since the details and variations of the present invention can be understood by those skilled in the art from the disclosure of the present invention, the repetitive description is omitted here for the sake of avoiding unnecessary detail without affecting the disclosure requirements and the feasibility of the present invention. It should be noted that the shapes, sizes, proportions, and sequence of steps of the components and steps shown in the drawings are illustrative only and are not intended to be limiting, since those skilled in the art will recognize the present invention.

Although the embodiments of the present invention have been described above, these embodiments are not intended to limit the present invention, and those skilled in the art can make variations on the technical features of the present invention according to the explicit or implicit contents of the present invention, and all such variations may fall within the scope of the patent protection sought by the present invention.

[ notation ] to show

100. 200, 700 dual-channel microphone system

110 double-track microphone

120. 220, 720 audio codec

112. 114 microphone

VDD voltage source

SLC1, SLC2 select pin

cp1 and cp2 frequency pin

dp1, dp2 data output pin

CLK frequency

D1, D2, D data

D _ PCM pulse code modulation data

value1, value2 bit value

Z high impedance

225. 725 capacitor

230 test circuit

740 processor

750 memory

410 comparison circuit

420 counter

430 decision circuit

CR comparison results

CV count value

Th threshold

FG flag

500 logic gate

S510 to S536 and S810 to S840.

Claims

1. A kind of test circuit, is used for testing the microphone of a pair of sound channels, this microphone of a pair of sound channels is according to a frequency movement and includes a first microphone and a second microphone, this first microphone outputs a first data through a first data output pin in a first quasi position of this frequency, this second microphone outputs a second data through a second data output pin in a second quasi position of this frequency, this first quasi position is not equal to this second quasi position, and this first data output pin and this second data output pin couple a electric capacity, this test circuit includes:

a comparison circuit for comparing the first data with the second data and generating a comparison result;

a counter coupled to the comparison circuit for generating a count value according to the comparison result; and

a decision circuit coupled to the counter for indicating whether the dual-channel microphone is faulty or not according to the count value and a threshold.

2. The test circuit of claim 1, wherein the first data and the second data are one-bit data, the comparison circuit is a logic gate, a first input of the logic gate receives the first data, a second input of the logic gate receives the second data, and an output of the logic gate outputs the comparison result.

3. The test circuit of claim 1, wherein the counter increments the count value when the comparison result indicates that the first data is equal to the second data; when the comparison result indicates that the first data is not equal to the second data, the counter resets the count value; and when the count value is larger than the threshold value, the decision circuit indicates that the two-channel microphone is in error.

4. A testing method is used for testing a dual-channel microphone, the dual-channel microphone acts according to a frequency and comprises a first microphone and a second microphone, the first microphone outputs a first data through a first data output pin at a first level of the frequency, the second microphone outputs a second data through a second data output pin at a second level of the frequency, the first level is not equal to the second level, and the first data output pin and the second data output pin are coupled with a capacitor, the testing method comprises the following steps:

(a) comparing the first data with the second data and generating a comparison result;

(b) generating a count value according to the comparison result; and

(c) and indicating whether the dual-channel microphone has errors or not according to the counting value and a threshold value.

5. The test method of claim 4, wherein the step (b) increases the count value when the comparison result indicates that the first data is equal to the second data; the step (b) resets the count value when the comparison result indicates that the first data is not equal to the second data; and when the count value is greater than the threshold value, the step (c) indicates that the two-channel microphone is in error.

6. A testing method is used for testing a dual-channel microphone, the dual-channel microphone acts according to a frequency and comprises a first microphone and a second microphone, the first microphone outputs a plurality of first data through a first data output pin at a first level of the frequency, the second microphone outputs a plurality of second data through a second data output pin at a second level of the frequency, the first level is not equal to the second level, and the first data output pin and the second data output pin are coupled with a capacitor, the testing method comprises the following steps:

(a) decoding or filtering the first data and the second data to generate first pulse code modulation data and second pulse code modulation data;

(b) comparing the first pulse code modulation data with the second pulse code modulation data and generating a comparison result;

(c) generating a count value according to the comparison result; and

(d) and indicating whether the dual-channel microphone has errors or not according to the counting value and a threshold value.

7. The test method according to claim 6, wherein the step (c) increases the count value when the comparison result indicates that the first pulse code modulation data is equal to the second pulse code modulation data; the step (c) resets the count value when the comparison result indicates that the first pulse code modulation data is not equal to the second pulse code modulation data; and when the count value is greater than the threshold value, the step (d) indicates that the two-channel microphone is faulty.

8. An audio codec for testing a dual-channel microphone, the dual-channel microphone operating according to a frequency and comprising a first microphone and a second microphone, the first microphone outputting a plurality of first data through a first data output pin at a first level of the frequency, the second microphone outputting a plurality of second data through a second data output pin at a second level of the frequency, the first level not being equal to the second level, and the first data output pin and the second data output pin being coupled to a capacitor, the audio codec comprising:

a memory for storing a plurality of program instructions or program codes;

a processor, coupled to the memory, for executing the program instructions or program codes to perform the following operations:

(c) generating a count value according to the comparison result; and

9. The audio codec of claim 8, wherein the step (c) increases the count value when the comparison result indicates that the first pulse code modulation data is equal to the second pulse code modulation data; the step (c) resets the count value when the comparison result indicates that the first pulse code modulation data is not equal to the second pulse code modulation data; and when the count value is greater than the threshold value, the step (d) indicates that the two-channel microphone is faulty.