CN112822610A - DSP-based stereo power amplifier no-signal automatic muting method and system - Google Patents
DSP-based stereo power amplifier no-signal automatic muting method and system Download PDFInfo
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- CN112822610A CN112822610A CN202110048046.0A CN202110048046A CN112822610A CN 112822610 A CN112822610 A CN 112822610A CN 202110048046 A CN202110048046 A CN 202110048046A CN 112822610 A CN112822610 A CN 112822610A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R5/00—Stereophonic arrangements
- H04R5/04—Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2205/00—Details of stereophonic arrangements covered by H04R5/00 but not provided for in any of its subgroups
- H04R2205/041—Adaptation of stereophonic signal reproduction for the hearing impaired
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2430/00—Signal processing covered by H04R, not provided for in its groups
- H04R2430/01—Aspects of volume control, not necessarily automatic, in sound systems
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Abstract
The invention discloses a DSP-based stereo power amplifier no-signal automatic mute method and a system, comprising an audio codec, a digital signal processor, a power amplifier and a main controller; the audio coder-decoder converts the analog audio signals of the left channel and the right channel into audio digital signals; the digital signal processor processes the audio digital signal, and the audio codec converts the processed audio digital signal into an analog signal and sends the analog signal to the input end of the power amplifier; the main controller sends a mute signal or cancels the mute signal to the power amplifier according to the audio digital signal processed by the audio codec. According to the invention, through the cooperation of the main controller and the DSP, after an input level is obtained, a series of analysis is carried out, the switch of the power amplifier can be automatically controlled, the mute is turned off when a signal is input, and the mute is turned on when no signal is input, so that the mute is automatically turned off when no signal is input, and the power amplifier bottom noise is thoroughly eliminated.
Description
Technical Field
The invention relates to the technical field of audio processing, in particular to a DSP-based stereo power amplifier signal-free automatic muting method and system.
Background
In the application of the traditional stereo power amplifier, for the power amplifier bottom noise without signal input, a noise gate is usually built through a DSP to remove the previous stage input noise of the power amplifier, the noise gate has a threshold value, when the DSP detects that the input signal level is smaller than the noise gate threshold value, the noise gate can cut off the signal output, when the signal level is larger than the noise gate threshold value, the signal can be normally output, and the method plays a role in inhibiting the bottom noise.
Disclosure of Invention
The invention aims to solve the technical problems that the prior art can only remove noise input to a DSP (digital signal processor) and can not completely remove the bottom noise of the whole power amplifier system, and aims to provide a DSP-based stereo power amplifier signal-free automatic muting method and system, so that the problem of completely removing the bottom noise of the system under the condition of no signal input is solved.
The invention is realized by the following technical scheme:
a DSP-based stereo power amplifier signal-free automatic mute method comprises an audio codec, a digital signal processor, a power amplifier and a main controller; the method comprises the following steps: step S1: the audio codec converts analog audio signals of a first channel and a second channel into audio digital signals; the digital signal processor processes the audio digital signal, and the audio codec converts the processed audio digital signal into an analog signal and sends the analog signal to the input end of the power amplifier; step S2: and the main controller sends a mute signal or cancels the mute signal to the power amplifier according to the audio digital signal processed by the audio codec.
The invention firstly carries out AD and DA conversion and digital signal processing on original analog audio signals input by a left channel and a right channel, on one hand, the audio signals are input to a power amplifier, on the other hand, a main controller is matched with a digital signal processor, and after a series of analysis is carried out according to the audio digital signals processed by an audio codec, a mute signal is determined to be sent to the power amplifier or the mute signal is cancelled, so that the on-off of the power amplifier can be automatically controlled. When a signal is input, the mute is closed, and when no signal exists, the mute is opened, so that the aims of moving the mute when no signal exists and thoroughly eliminating the power amplifier noise floor are fulfilled.
Further, the step S2 includes: step S21: acquiring a first sound channel level and a second sound channel level, and acquiring a counting set according to the first sound channel level and the second sound channel level; step S22: controlling the power amplifier according to the count set.
Further, in step S21, a processed audio digital signal is obtained, and the processed audio digital signal is divided into a first channel level and a second channel level.
Further, in step S22, the count set includes: a first channel level on count M, a second channel level on count N, a first channel level off count I, and a second channel level off count J.
Further, the initial values of the count sets are all 0;
if the first channel level is greater than the set threshold, M +1, I0;
if the second channel level is greater than the set threshold, N is N +1, and J is 0;
if the first channel level is less than the set threshold, M is 0, I is I + 1;
if the second channel level is less than the set threshold, N is 0 and J is J + 1.
Further, if M is greater than a first predetermined value or N is greater than the first predetermined value, then M is 0 and N is 0, and a mute cancellation signal is sent to the power amplifier; and if I is larger than a second preset value and J is larger than the second preset value, I is 0, and J is 0, and the mute signal is sent to the power amplifier.
Further, the first predetermined value is in the range of 8-10, and the second predetermined value is in the range of 80-120.
Further, when the first channel is a left channel, the second channel is a right channel; and when the first channel is a right channel, the second channel is a left channel.
Further, a mute signal or a cancel mute signal is sent to the power amplifier through a pin.
The invention also discloses another implementation mode, in particular to a DSP-based stereo power amplifier signal-free automatic muting system, which realizes any one of the automatic muting methods, and comprises an audio codec, a digital signal processor, a power amplifier, a main controller and a sound device; the audio decoder is connected with the digital signal processor and the power amplifier, the main controller is connected with the digital signal processor and the power amplifier, and the power amplifier is connected with sound equipment; the audio decoder is connected with the digital signal processor through an IIS bus; and the digital signal processor is connected with the main controller through an IIC bus.
Compared with the prior art, the invention has the following advantages and beneficial effects:
according to the invention, through the cooperation of the main controller and the DSP, after an input level is obtained, a series of analysis is carried out, the switch of the power amplifier can be automatically controlled, the mute is turned off when a signal is input, and the mute is turned on when no signal is input, so that the mute is automatically turned off when no signal is input, and the power amplifier bottom noise is thoroughly eliminated.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 is a block diagram of the system of the present invention;
FIG. 2 is a flow chart of the method of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.
Example 1
This embodiment 1 is a DSP-based no-signal automatic mute method for stereo power amplification, which includes an audio codec, a digital signal processor, a power amplifier, and a main controller.
The method comprises the following steps: step S1: the audio codec converts analog audio signals of a first channel and a second channel into audio digital signals; the digital signal processor processes the audio digital signal, and the audio codec converts the processed audio digital signal into an analog signal and sends the analog signal to the input end of the power amplifier.
Step S2: the main controller sends a mute signal or cancels the mute signal to the power amplifier according to the audio digital signal processed by the audio codec. The method specifically comprises the following substeps:
step S21: acquiring a processed audio digital signal, and dividing the processed audio digital signal into a first channel level and a second channel level; acquiring a counting set according to the first channel level and the second channel level;
step S22: the power amplifier is controlled according to the count set. The count set includes: a first channel level on count M, a second channel level on count N, a first channel level off count I, and a second channel level off count J;
if the first channel level is greater than the set threshold, M +1, I0;
if the second channel level is greater than the set threshold, N is N +1, and J is 0;
if the first channel level is less than the set threshold, M is 0, I is I + 1;
if the second channel level is less than the set threshold, N is 0 and J is J + 1.
If M is larger than a first preset value or N is larger than the first preset value, M is 0, N is 0, and a mute cancellation signal is sent to the power amplifier; and if I is larger than a second preset value and J is larger than the second preset value, I is 0, and J is 0, and the mute signal is sent to the power amplifier. The range of the first preset value is any value between 8 and 10, and the range of the second preset value is any value between 80 and 120.
In this embodiment 1, when the first channel is a left channel, the second channel is a right channel; when the first channel is a right channel, the second channel is a left channel.
In this embodiment 1, first, the original analog audio signals input by the left and right channels are subjected to AD and DA conversion and digital signal processing, on one hand, the audio signals are input to the power amplifier, on the other hand, the main controller is matched with the digital signal processor, and after a series of analyses are performed according to the audio digital signals processed by the audio codec, it is determined to send a mute signal to the power amplifier or cancel the mute signal, so that the switching of the power amplifier can be automatically controlled. When a signal is input, the mute is closed, and when no signal exists, the mute is opened, so that the aims of moving the mute when no signal exists and thoroughly eliminating the power amplifier noise floor are fulfilled.
Another implementation manner of this embodiment 1 is a DSP-based stereo power amplifier no-signal automatic muting system, which implements any one of the above automatic muting methods, including an audio codec, a digital signal processor, a power amplifier, a main controller, and a sound device; the audio decoder is connected with the digital signal processor and the power amplifier, the main controller is connected with the digital signal processor and the power amplifier, and the power amplifier is connected with the sound equipment; the audio decoder is connected with the digital signal processor through an IIS bus; the digital signal processor is connected with the main controller through an IIC bus.
Example 2
This embodiment 2 is a DSP-based stereo power amplifier no-signal automatic mute system and method.
A DSP-based stereo power amplifier signal-free automatic mute system is shown in figure 1, an external analog input is connected with an audio codec, the codec converts an analog signal into a digital signal and transmits the digital signal to a DSP, the DSP transmits the processed digital signal to the codec through an iis bus, the codec converts the digital signal into an analog signal and outputs the analog signal to a power amplifier, a main controller is connected with the DSP through the iic bus and outputs a mute or non-mute signal to the power amplifier through a pin, and the output end of the power amplifier is connected with a sound box. Audio codec, dsp, digital signal processor and power amplifier.
As shown in fig. 2, after a DSP power amplifier is powered on and started, a main controller first reads the levels of two input signals in the DSP through an IIC bus, and then sequentially determines the levels of left and right channels, if the level of the left channel or the right channel is greater than a set threshold, a corresponding level open counter is incremented by 1, a level close counter is cleared, and if the level of the left channel or the right channel is less than or equal to the set threshold, the corresponding level close counter is incremented by 1, and the level open counter is cleared. Then judging whether the level opening counter of any one of the left channel or the right channel is more than 10, if so, indicating that the left channel or the right channel has a signal input higher than a set threshold value, clearing the level opening counter of the left channel or the right channel by the main controller, then sending a mute canceling signal to the power amplifier through a mute pin, if not, continuously judging whether the level closing counters of the left channel and the right channel are both more than 100, if so, indicating that the input signals of the two channels do not exceed the set threshold value, clearing the level closing counters of the left channel and the right channel by the main controller, then sending a mute signal to the power amplifier through the mute pin, if not, continuously returning to the starting position to continuously read the level, and continuing to make a judgment.
Since the actual audio signal is not a signal with a constant level, the level thereof has an amplitude fluctuating with time, and if a counting process is not performed on the level, a misjudgment may be caused. Therefore, in this embodiment, the power amplifier is not directly controlled after the input left and right channel levels are determined, and a method of counting the opening or closing of the left and right channels is adopted.
By building the system platform shown in fig. 1, the main controller can automatically perform a series of processing on the input level, so that the power amplifier is controlled to turn off mute when a signal is input, turn on mute when no signal is input, and achieve the effect of automatic mute when no signal is input.
Example 3
In this embodiment 3, based on the embodiment 2, the FFT algorithm calculates the amplitude-frequency response, and is described by obtaining the detection result by performing spectrum analysis on the digital signal by using the FFT in the slave, including the following steps:
1. the digital microphone collects audio signals and sends the signals to the slave through an i2s bus;
2. the slave computer enters a recording mode;
3. the slave machine defines five buffer spaces, each buffer space stores 1024 points of recording data, and the purpose of defining the five buffer spaces is to calculate an FFT result and then take an average value, so that the result judgment error caused by some errors is avoided;
4. after the five buffer spaces receive the data, starting to perform FFT (fast Fourier transform);
5. setting the number of FFT points to be 1024;
6. transferring 1024 points of sound recording data in one of the five buffer spaces as parameters to an FFT function;
7. calculating by adopting an FFT floating point algorithm of a base 4 to obtain a complex value of each frequency point (the FFT also has an algorithm of a base 2, and is not used);
8. obtaining the amplitude by taking the modulus of the operation result;
9. repeating the three steps of 6, 7 and 8 to obtain FFT results of five buffer spaces;
10. summing the FFT results of the five buffer spaces and then averaging to obtain an average FFT result;
11. adding the amplitudes of all frequency points in a set low-frequency range (such as 20 Hz-300 Hz) and averaging to obtain the average amplitude of the low frequency;
12. adding the amplitudes of all frequency points in a set intermediate frequency range (such as 500 Hz-2000 Hz) and averaging to obtain an average amplitude of the intermediate frequency;
13. adding the amplitudes of all frequency points in a set high-frequency range (such as 5000 Hz-8000 Hz) and averaging to obtain the average amplitude of the high frequency;
14. comparing the obtained average amplitude of the low, medium and high with the average amplitude of the single frequency point of the normal loudspeaker, and regarding the loudspeaker as abnormal if the average amplitude exceeds +/-15% of the normal range. (before shipment, the average amplitude of a single bin for a group of normal speakers will be tested).
In the present invention, it is determined whether the on counter of the left and right channels is greater than 10, where the number 10 is a preferred value, and other values may be taken according to the needs of the actual situation. Meanwhile, it is determined that the level off counters of the left and right channels are not both greater than 100, and here, the number 100 is also an optimal value, and other approximate values may be taken according to the needs of the actual situation.
In the invention, the set threshold of the judgment level can be in the range of-60 to-80, and the specific content can be determined according to the actual situation.
In the present invention, the main controller may be a chip processor in the prior art.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A DSP-based stereo power amplifier signal-free automatic mute method is characterized by comprising an audio codec, a digital signal processor, a power amplifier and a main controller; the method comprises the following steps:
step S1: the audio codec converts analog audio signals of a first channel and a second channel into audio digital signals; the digital signal processor processes the audio digital signal, and the audio codec converts the processed audio digital signal into an analog signal and sends the analog signal to the input end of the power amplifier;
step S2: and the main controller sends a mute signal or cancels the mute signal to the power amplifier according to the audio digital signal processed by the audio codec.
2. The DSP-based stereo power amplifier signal-free automatic muting method of claim 1, wherein the step S2 comprises:
step S21: acquiring a first sound channel level and a second sound channel level, and acquiring a counting set according to the first sound channel level and the second sound channel level;
step S22: controlling the power amplifier according to the count set.
3. The DSP-based stereo power amplifier signal-free automatic muting method of claim 2, wherein in the step S21, a processed audio digital signal is obtained, and the processed audio digital signal is divided into a first channel level and a second channel level.
4. The DSP-based stereo power amplifier signal-free automatic muting method of claim 2, wherein in the step S22, the count set comprises: a first channel level on count M, a second channel level on count N, a first channel level off count I, and a second channel level off count J.
5. The DSP-based stereo power amplifier signal-free automatic muting method according to claim 4, characterized in that initial values of the count sets are all 0;
if the first channel level is greater than the set threshold, M +1, I0;
if the second channel level is greater than the set threshold, N is N +1, and J is 0;
if the first channel level is less than the set threshold, M is 0, I is I + 1;
if the second channel level is less than the set threshold, N is 0 and J is J + 1.
6. The DSP-based stereo power amplifier signal-free automatic muting method of claim 5, wherein if M is greater than a first predetermined value or N is greater than a first predetermined value, M-0, N-0, sending a mute cancellation signal to the power amplifier;
and if I is larger than a second preset value and J is larger than the second preset value, I is 0, and J is 0, and the mute signal is sent to the power amplifier.
7. The DSP-based stereo power amplifier signal-free automatic muting method according to claim 6, wherein the first predetermined value is in a range of 8-10 and the second predetermined value is in a range of 80-120.
8. The DSP-based stereo power amplifier signal-free automatic muting method of claim 1, wherein when the first channel is a left channel, the second channel is a right channel; and when the first channel is a right channel, the second channel is a left channel.
9. The DSP-based stereo power amplifier signal-less automatic muting method of claim 1, wherein the muting signal is sent or canceled to the power amplifier through a pin.
10. A DSP-based stereo power amplifier signal-free automatic mute system is characterized by comprising an audio codec, a digital signal processor, a power amplifier, a main controller and a sound device;
the audio decoder is connected with the digital signal processor and the power amplifier, the main controller is connected with the digital signal processor and the power amplifier, and the power amplifier is connected with sound equipment; the audio decoder is connected with the digital signal processor through an IIS bus; the digital signal processor is connected with the main controller through an IIC bus;
the DSP-based stereo power amplifier signal-free automatic muting system realizes the DSP-based stereo power amplifier signal-free automatic muting method in any one of claims 1-8.
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Cited By (1)
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Application publication date: 20210518 |