CN110868672B - Loudspeaker signal protection device and method - Google Patents
Loudspeaker signal protection device and method Download PDFInfo
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- CN110868672B CN110868672B CN201810990834.XA CN201810990834A CN110868672B CN 110868672 B CN110868672 B CN 110868672B CN 201810990834 A CN201810990834 A CN 201810990834A CN 110868672 B CN110868672 B CN 110868672B
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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
- H04R3/00—Circuits for transducers, loudspeakers or microphones
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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
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Abstract
The embodiment of the invention provides a loudspeaker signal protection device and method. The device comprises one or more signal protection modules which are connected in sequence; the input end of the signal protection module is used for receiving a first audio signal to be processed or is connected with the signal protection module connected in front, and the output end of the signal protection module is connected with the signal protection module connected in back or outputs the processed audio signal; the signal protection module comprises a first gain device and a first gain calculator; the input end of the first gain calculator is used for receiving a first audio signal to be processed, and the output end of the first gain calculator is connected with the input end of the first gain calculator; the input end of the first booster is also used for receiving a first audio signal to be processed, and the output end of the first booster is connected with a signal protection module connected behind or outputs the processed first audio signal, so that signal protection of the target loudspeaker is realized.
Description
Technical Field
The embodiment of the invention relates to the field of loudspeaker control, in particular to a loudspeaker signal protection device and method.
Background
With the popularization and popularity of portable intelligent devices, people have higher requirements on the audio playback effect of portable devices. This makes it necessary for manufacturers to fully exploit the performance of the loudspeaker under conditions limited by many parties. The limitations here are on the one hand the ability of the loudspeaker to withstand the mechanical displacements of the diaphragm and the temperature of the coil, and on the other hand the upper limit of the voltage amplitude that can be output by the device (e.g. power amplifier) itself that outputs the electrical signal to the loudspeaker. The latter presence allows manufacturers to introduce truncation distortion into the output signal if the gain on the signal link is increased in an undesirable manner in pursuit of better playback. This, while not necessarily directly causing damage to the speaker, can cause significant deterioration in the audible perception and is therefore to be avoided.
In view of the above problems, the prior art compares the input signal of the loudspeaker with N (N ≧ 2) thresholds of different levels, and the higher the threshold exceeded by the input signal, the faster the device will reduce the gain on the input link. The typical application method is to use a "first threshold value for monitoring the truncation distortion", and to set a "second preset threshold value" to a level value corresponding to the rated power value of the speaker, thereby limiting the speaker to its rated power or below most of the time, and avoiding the truncation distortion while allowing the speaker to operate with a short excess of the rated power.
However, since the above method is based on a feedback loop, it is only able to react after the truncation distortion actually occurs, and it is even impossible to predict the truncation distortion in advance and to respond in advance, so that it is impossible to fundamentally avoid the harm caused by the truncation distortion.
Disclosure of Invention
Aiming at the problems in the prior art, the embodiment of the invention provides a loudspeaker signal protection device and a loudspeaker signal protection method.
In a first aspect, an embodiment of the present invention provides a speaker signal protection apparatus, including:
one or more signal protection modules connected in sequence; the input end of the signal protection module is used for receiving a first audio signal to be processed or is connected with the signal protection module connected in front, and the output end of the signal protection module is connected with the signal protection module connected in back or outputs the processed audio signal;
the signal protection module comprises a first gain device and a first gain calculator;
the input end of the first gain calculator is used for receiving a first audio signal to be processed, and the output end of the first gain calculator is connected with the input end of the first gain calculator;
the input end of the first booster is also used for receiving a first audio signal to be processed, and the output end of the first booster is connected with a signal protection module connected behind or outputs the processed first audio signal.
In a second aspect, an embodiment of the present invention provides a loudspeaker signal protection method based on the loudspeaker signal protection apparatus in the first aspect, including:
acquiring a first target gain value according to an instantaneous value or a peak value of a first audio signal to be processed and a rated maximum voltage of a current signal link;
and performing gain on the first audio signal to be processed according to the first target gain value and outputting the first audio signal to be processed.
According to the loudspeaker signal protection device and the loudspeaker signal protection method based on the loudspeaker signal protection device, the temperature protection module is constructed through the gain device and the gain calculator, the gain calculation is carried out according to the instantaneous value or the peak value of the input audio signal and the rated maximum voltage of the current signal link, the truncation distortion can be predicted in advance, the gain value required for avoiding the signal truncation distortion is obtained, and the gain is carried out through the gain device, so that the signal protection of the target loudspeaker is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the description of the embodiments or the prior art, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a first structure of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a second structure of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a third structure of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 4 is a fourth structural diagram of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 5 is a fifth structural diagram of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 6 is a sixth structural schematic diagram of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a first structure of a temperature protection module of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 8 is a schematic diagram of a second structure of a temperature protection module of a speaker signal protection apparatus according to an embodiment of the present invention;
fig. 9 is a first flowchart of a speaker signal protection method according to an embodiment of the invention;
fig. 10 is a second flowchart of a speaker signal protection method according to an embodiment of the invention.
Description of the reference numerals
1. Upstream equipment, 2, a temperature protection module, 4, a target horn,
5. a signal protection module, 21, a second delayer, 22, a second booster,
23. a second detector, 24, a second gain calculator, 51, a first delayer,
52. a first booster, 53, a first peak detector, 54, a first gain calculator.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In view of the foregoing, embodiments of the present invention provide a speaker signal protection device and a speaker signal protection method based on the speaker signal protection device, so as to solve the problems in the prior art.
Fig. 1 is a schematic diagram of a first structure of a speaker signal protection apparatus according to an embodiment of the present invention. The embodiment of the invention provides a loudspeaker signal protection device, which comprises: one or more signal protection modules 5 connected in sequence; the input end of the signal protection module 5 is used for receiving a first audio signal to be processed or is connected with the signal protection module 5 connected in front, and the output end of the signal protection module 5 is connected with the signal protection module 5 connected in back or outputs the processed audio signal;
the signal protection module 5 includes a first gain calculator 52 and a first gain calculator 54;
the input end of the first gain calculator 54 is used for receiving a first audio signal to be processed, and the output end is connected with the input end of the first booster 52;
the input end of the first booster 52 is further configured to receive a first audio signal to be processed, and the output end is connected to the signal protection module 5 connected in the rear or outputs the processed first audio signal.
The first gain calculator 54 is configured to compare an instantaneous value of the first audio signal to be processed with a rated maximum voltage of a current signal link, and obtain a first target gain value;
specifically, the gain value calculated by the first gain calculator 54 may be set as the first target gain value, or a value obtained by smoothing the gain value calculated by the first gain calculator 54 may be set as the first target gain value. Specifically, the smoothing process for the gain value calculated by the first gain calculator 54 may be implemented by an envelope detector (envelope detector) with adjustable start time (attack time), recovery time (release time), and hold time (hold time).
The first booster 52 is configured to gain and output the first audio signal to be processed according to the first target gain value.
Referring to fig. 1, the speaker signal protection apparatus shown in fig. 1 includes a signal protection module 5, where the signal protection module 5 receives a first audio signal to be processed provided by any upstream device 1, and the first audio signal to be processed may be subjected to any other processing upstream. In the embodiment of the present invention, the first audio signal to be processed is duplicated into two identical audio signals, wherein one of the audio signals is directly input to the first gain calculator 52, and the other audio signal is input to the first gain calculator 54 and then input to the first gain calculator 52; the first gain calculator 52 has one input terminal for receiving the first audio signal to be processed and another input terminal for receiving the output signal of the first gain calculator 54, wherein the output signal of the first gain calculator 54 is the first target gain value required for signal protection. Thus, the first gain device 52 receives two input signals, one is the first audio signal to be processed, and the other is the first target gain value output by the first gain calculator 54, and the first gain device 52 gains the first audio signal to be processed according to the target gain value and outputs the first audio signal after the gain; if the output end of the first booster 52 is connected to the target speaker 4, the first audio signal after being boosted is output to the target speaker 4.
It should be noted that the target speaker is a speaker that receives the audio signal output by the speaker signal protection apparatus according to the embodiment of the present invention, and will not be described in detail hereinafter. In all embodiments of the present invention, the upstream device 1 and the target loudspeaker 4 are external devices, which do not belong to the loudspeaker signal protection apparatus in the embodiments of the present invention, and will not be described again.
Fig. 2 is a schematic diagram of a second structure of a speaker signal protection apparatus according to an embodiment of the present invention, where the speaker signal protection apparatus shown in fig. 2 includes two signal protection modules 5, a first signal protection module 5 receives a first audio signal to be processed provided by an upstream device 1, and outputs the first audio signal to a signal protection module 5 (referred to as a second signal protection module) connected to the first signal protection module after signal protection processing, and at this time, the processed first audio signal output by the first signal protection module 5 serves as a first audio signal to be processed by the second signal protection module. If the rear of the second signal protection module is also connected with a signal protection module 5, and so on, the output of the former signal protection module is used as the input of the latter signal protection module, and the output of the last signal protection module is used as the final output signal. If the output end of the last signal protection module is connected with the target loudspeaker 4, the first audio signal after the gain, namely the audio signal output by the last signal protection module, is output to the target loudspeaker 4.
In this embodiment, fig. 1 shows a speaker signal protection device including one signal protection module 5, fig. 2 shows a speaker signal protection device including two signal protection modules 5, and further, signal protection may be implemented by sequentially connecting more signal protection modules, and internal parameters of each signal module may be different, which is not described herein again.
The above-mentioned serial connection of multiple signal protection modules can be used to set multiple signal thresholds and set different time constants for different signal thresholds.
It should be noted that, in all embodiments of the present invention, the gain value calculated by the gain calculator may be used as the target gain value, or a value obtained by smoothing the gain value calculated by the gain calculator may be used as the target gain value, which is not described herein again. Specifically, the smoothing process for the gain value calculated by the first gain calculator 54 may be implemented by an envelope detector (envelope detector) with adjustable start time (attack time), recovery time (release time), and hold time (hold time).
According to the embodiment of the invention, the signal protection module is constructed through the gain device and the gain calculator, the gain calculation is carried out according to the peak value of the input audio signal and the rated maximum voltage of the current signal link, the gain value required by signal protection is obtained, the truncation distortion can be predicted in advance, the gain value required by avoiding the signal truncation distortion is obtained, and the gain is carried out through the gain device, so that the signal protection of the target loudspeaker is realized. The embodiment of the invention realizes the signal protection of the loudspeaker through 1 or more signal protection modules, has simple structure and low software and hardware expenditure.
Fig. 3 is a schematic diagram of a third structure of a speaker signal protection apparatus according to an embodiment of the present invention, and based on the above embodiment, the signal protection module further includes a first peak detector 53;
the first peak detector 53 has an input for receiving a first audio signal to be processed and an output connected to the input of the first gain calculator 54.
Specifically, the first peak detector 53 is configured to detect a peak value of a first audio signal to be processed, and output the detected peak value to the first gain calculator 52;
in the case where the peak detector is not added to the signal protection module of the previous embodiment, the first gain calculator 54 compares the instantaneous value of the first audio signal to be processed with the rated maximum voltage of the current signal link to perform a gain calculation. In this embodiment, the first gain calculator 54 is configured to compare a peak value of the first audio signal to be processed with a rated maximum voltage of the current signal link, and obtain a first target gain value.
The embodiment is suitable for the case that a plurality of signal protection modules in fig. 2 are connected in series, and each signal protection module may be added with a peak detector completely or partially, and may be flexibly combined as required.
In particular, peak detectors have a number of existing non-proprietary implementations in the digital and analog domains to choose from, for example: the peak detector can be realized in an analog mode as an analog peak detection circuit, and can also be realized in a digital mode as a digital peak detector which is basically equivalent to the analog peak detection circuit.
Fig. 4 is a schematic diagram of a fourth structure of a speaker signal protection apparatus according to an embodiment of the present invention, and based on the above embodiment, the signal protection module 5 further includes a first delayer 51;
the input of the first delay 51 is used for receiving a first audio signal to be processed, and the output is connected to the input of the first booster 52.
Specifically, the first delayer 51 is configured to delay a first audio signal to be processed for a first preset time and output the delayed first audio signal to the first gainer 52.
Referring to fig. 4, after the first audio signal to be processed is copied into two identical audio signals, one of the audio signals is input into the first delayer 51, delayed and input into the first gainer 52, and the other of the audio signals is input into the peak detector 53, passed through the first gain calculator 54, and input into the first gainer 52.
Similarly, this embodiment is applicable to the case where a plurality of signal protection modules in fig. 2 are connected in series, and all or part of the signal protection modules may be added with a delay device, and may be flexibly combined as required.
FIG. 5 is a fifth structural diagram of a speaker signal protection apparatus according to an embodiment of the present invention,
fig. 6 is a schematic diagram of a sixth structure of a speaker signal protection apparatus according to an embodiment of the present invention, which includes, based on the above embodiment: a temperature protection module 2; the input end of the temperature protection module 2 is connected with any signal protection module 5, and the output end is connected with the subsequent signal protection module 5 (as shown in fig. 6) or used for outputting a processed audio signal (as shown in fig. 5);
fig. 7 is a schematic diagram of a first structure of a temperature protection module according to an embodiment of the present invention, where the temperature protection module 2 includes a second detector 23, a second gain calculator 24, and a second gain calculator 22;
the second detector 23 is a root-mean-square detector or a mean-square detector, an input end of the second detector is used for receiving a second audio signal to be processed, and an output end of the second detector is connected with an input end of the second gain calculator 24; the second audio signal to be processed is an audio signal output by the signal protection module 5 connected in advance;
the output end of the second gain calculator 24 is connected with the input end of the second booster 22;
the input end of the second booster 22 is further configured to receive the second audio signal to be processed, and the output end is configured to output the processed second audio signal.
Specifically, the second detector 23 may be a root mean square detector (RMS detector) or a mean square detector (MS detector); if the second detector 23 is a root-mean-square detector, the second detector is configured to obtain a root-mean-square of the second audio signal to be processed in a first preset time window; if the second detector 23 is a mean square value detector, it is configured to obtain a mean square value of the second audio signal to be processed within a first preset time window. In the embodiment of the present invention, the second detector 23 may obtain a root mean square or a mean square value of the second audio signal in the first preset time window, and output the root mean square or the mean square value to the second gain calculator 24.
The second gain calculator 24 is configured to obtain a second target gain value required by the target loudspeaker according to the root mean square or the mean square value and a threshold determined by the rated power of the target loudspeaker;
the second booster 22 is configured to boost and output the second audio signal to be processed according to the second target gain value.
It should be noted that the time length of the first preset time window may be selected according to actual needs, and this is not specifically limited in the embodiment of the present invention.
Referring to fig. 5 and 6, in the speaker signal protection apparatus according to the embodiment of the present invention, signal protection and temperature protection for a speaker are implemented by the signal protection module 5 and the temperature protection module 2, wherein the structure of the temperature protection module 2 refers to fig. 7. In a specific application environment, the temperature protection module 2 receives the first audio signal processed by the signal protection module connected in front as the second audio signal to be processed. In the embodiment of the present invention, the signal protection module 5 outputs two identical audio signals (without the first delayer 51), or the signal protection module 5 outputs two audio signals with time difference (with the first delayer 51), so that the to-be-processed second audio signal received by the temperature protection module 2 is two audio signals with time difference or without time difference output by the signal protection module 5, wherein one audio signal is directly input to the second multiplier 22, and the other audio signal is input to the second detector 23, passes through the second gain calculator 24, and is input to the second multiplier 22; the second booster 22 has an input terminal for receiving the second audio signal to be processed and another input terminal for receiving the output signal of the second gain calculator 24, wherein the output signal of the second gain calculator 24 is the second target gain value required for temperature protection. Thus, the second booster 22 receives two input signals, one is the second audio signal to be processed, and the other is the second target gain value output by the second gain calculator 24, and the second booster 22 performs gain on the second audio signal to be processed according to the target gain value and outputs the second audio signal after gain; if the output end of the second booster 22 is connected to the target speaker 4, the second audio signal after being boosted is output to the target speaker 4. If the output end of the second booster 22 is connected to the signal protection module 5 connected in the rear, the second audio signal after being boosted is output to the signal protection module 5 connected in the rear, and is used as the first audio signal to be processed of the signal protection module 5 connected in the rear.
Specifically, the gain value calculated by the second gain calculator 24 may be set as the second target gain value, or a value obtained by smoothing the gain value calculated by the second gain calculator 24 may be set as the second target gain value. Specifically, the smoothing process for the gain value calculated by the second gain calculator 24 may be implemented by an envelope detector (envelope detector) with adjustable start time (attack time), recovery time (release time), and hold time (hold time).
Specifically, the second detector 23 has a variety of existing non-proprietary implementations in the digital and analog domains, for example:
one of them can be realized in an analog manner as a pseudo-root-mean-square detector (fake rms detector) consisting of a rectifying circuit and a filtering circuit.
And secondly, the square detector can also be digitally implemented as a root mean square detector or a mean square detector which is subjected to square operation and a section of smoothing processing with adjustable window size.
In particular, the gain calculator has a variety of existing non-proprietary implementations available in the digital and analog domains.
It should be noted that, in the speaker signal protection apparatus according to the embodiment of the present invention, each component in the temperature protection module 2, such as the second detector 23, the second gain calculator 24, and the second gain calculator 22, may be implemented entirely in the digital domain, entirely in the analog domain, or partly in the digital domain and partly in the analog domain.
According to the embodiment of the invention, the temperature protection module is constructed by the second detector, the gain calculator and the gain device, the gain calculation is carried out according to the mean square value of the input audio signal and the threshold value determined by the rated power of the target loudspeaker, the gain value required by temperature protection is obtained, and the gain is carried out by the gain device, so that the temperature protection of the target loudspeaker is realized.
Fig. 8 is a schematic diagram of a second structure of the temperature protection module according to the embodiment of the invention. Based on the above embodiment, the temperature protection module 2 further includes a second delayer 21;
the input end of the second delay unit 21 is configured to receive the second audio signal to be processed, and the output end is connected to the input end of the second booster 22.
Specifically, the second delayer 21 is configured to delay a second audio signal to be processed for a first preset time, and output the second audio signal to the second gainer 22.
Referring to fig. 8, the second audio signal to be processed includes two audio signals, one of the audio signals is input to the second delayer 21, delayed and input to the second gainer 22, the other of the audio signals is input to the second detector 23, passes through the second gain calculator 24, and input to the second gainer 22.
The specific preset time may be determined according to the needs of practical applications, and the embodiment of the present invention is not limited in this respect.
The embodiment of the invention delays the audio signal to be processed, and has the advantage that the final output power can be ensured to be in a required range by reducing the gain in advance under the application scene that the power needs to be strictly controlled.
In summary, the speaker signal protection device according to the embodiments of the present invention has a simple structure, and can implement flexible and various software and hardware structures, and each component of each speaker signal protection device embodiment can be implemented entirely in a digital domain, entirely in an analog domain, or partly in the digital domain and partly in the analog domain, so that it can provide effective temperature protection and signal protection with low software and hardware overhead.
It should be noted that, with the loudspeaker signal protection device according to the embodiment of the present invention, if the processed audio signal leaves the loudspeaker signal protection device and is further subjected to other linear processing before entering the loudspeaker, for example, filtering through a high-pass filter, etc., the following two changes may be made so that the control given by the gain calculator in the signal protection module conforms to the final actual requirement:
1. the same linear processing as described above, for example, a high pass filter, is added to the chain on which the gain calculator of the first signal protection module is located.
2. And respectively introducing signals before and after the linear processing on a link where the gain calculator of the first signal protection module is positioned into a subsequent module.
Fig. 9 is a schematic diagram of a first flow of a speaker signal protection method according to an embodiment of the present invention, and based on the speaker signal protection apparatus according to the embodiment of the present invention, an embodiment of the present invention provides a speaker signal protection method, including:
90, acquiring a first target gain value according to the instantaneous value or the peak value of the first audio signal to be processed and the rated maximum voltage of the current signal link;
and 91, performing gain on the first audio signal to be processed according to the first target gain value, and then outputting the first audio signal to be processed.
It should be noted that the method described in this embodiment may be implemented by the first structure of the speaker signal protection device shown in fig. 1, the second structure of the speaker signal protection device shown in fig. 2, or the third structure of the speaker signal protection device shown in fig. 3, and the specific steps 90 and 91 are executed by the signal protection module.
If the processing is performed according to the instantaneous value of the first audio signal to be processed, that is, the step 90 obtains the first target gain value according to the instantaneous value of the first audio signal to be processed and the rated maximum voltage of the current signal link, the method is implemented by the structure of fig. 1, and the first audio signal to be processed is the audio signal provided by the upstream device 1. If the method is implemented by the structure of fig. 2, that is, implemented by a plurality of signal protection modules connected in series, the first audio signal to be processed of the first signal protection module is the audio signal provided by the upstream device 1, and the first audio signal to be processed of the subsequent signal protection module is the output signal of the previous signal protection module. Referring to fig. 1, a first audio signal to be processed output from an upstream device 1 is input to the loudspeaker signal protection apparatus shown in fig. 1 in two paths, where one path of signal is directly input to a booster, which is a signal for gain output, the link is a main link, and the other path of signal is processed by a peak detector and a gain calculator and then input to the booster, which is called a bypass or a control link. In all embodiments of the present invention, a link for performing gain output on a signal is referred to as a main link, and a link for processing a signal to implement gain control is referred to as a control link, which will not be described in detail later. In this embodiment, an instantaneous value of a first audio signal to be processed is obtained, a rated maximum voltage of a current signal link is obtained, a gain calculator compares the instantaneous value of the first audio signal to be processed with the rated maximum voltage of the current signal link, a first target gain value which enables the current signal link to output an audio signal without clipping is obtained, and the first target gain value is output to a gain unit. The gain unit performs a gain on the first audio signal to be processed according to the first target gain value, and specifically, multiplies the audio signal input by the main link by the first target gain value and outputs the result.
If the processing is performed according to the peak value of the first audio signal to be processed, that is, step 90 obtains a first target gain value according to the peak value of the first audio signal to be processed and the rated maximum voltage of the current signal link, the method is implemented by using the structure of fig. 3, and the first audio signal to be processed is an audio signal provided by the upstream device 1. If the method is implemented by the structure of fig. 2, that is, implemented by a plurality of signal protection modules connected in series, the first audio signal to be processed of the first signal protection module is the audio signal provided by the upstream device 1, and the first audio signal to be processed of the subsequent signal protection module is the output signal of the previous signal protection module. In this embodiment, a peak value of a first audio signal to be processed is detected by a peak value detector, a rated maximum voltage of a current signal link is obtained, a gain calculator compares the peak value of the first audio signal to be processed with the rated maximum voltage of the current signal link, a first target gain value which enables the current signal link to output a signal without topping is obtained, and the first target gain value is output to a booster. The gain unit performs a gain on the first audio signal to be processed according to the first target gain value, and specifically, multiplies the audio signal input by the main link by the first target gain value and outputs the result.
The gain of the embodiment of the invention is as follows: the target gain value is used for controlling the amplification or attenuation of the signal, the purpose of controlling the average output power and the signal strength of the signal is to control the temperature protection, the signal protection and the like of the loudspeaker, and the details are not repeated hereafter.
In the embodiment of the invention, the instantaneous value or the peak value of the input signal is detected through one or more signal protection modules, and the target gain value is obtained according to the rated maximum voltage of the current signal link, so that the current signal link outputs the target gain value without topping, thereby realizing the signal protection of the target loudspeaker.
Based on the above embodiment, in step 91, the outputting the to-be-processed first audio signal after performing gain on the to-be-processed first audio signal according to the first target gain value further includes:
and smoothing the first target gain value, and taking the smoothed result as the first target gain value.
For the gain values calculated by all the gain calculators in all the embodiments of the present invention, the calculated gain value can be directly used as the target gain value, or the smoothed calculated gain value can be used as the target gain value, which is not described in detail hereinafter. Specifically, the smoothing process for the gain value calculated by the gain calculator may be implemented by an envelope detector (envelope detector) whose start time (attack time), recovery time (release time), and hold time (hold time) are respectively adjustable.
In this embodiment, a value obtained by smoothing the calculated gain value is used as the target gain value.
Based on the above embodiment, in step 91, the outputting the to-be-processed first audio signal after performing gain on the to-be-processed first audio signal according to the first target gain value specifically includes:
delaying the first audio signal to be processed for a first preset time;
and the delayed first audio signal to be processed is output after being gained according to the first target gain value.
It should be noted that the method described in this embodiment may be implemented by the fourth structure of the speaker signal protection device shown in fig. 4 or the second structure of the speaker signal protection device shown in fig. 2.
In the foregoing embodiment, the signal protection module directly gains the input audio signal without delay; in the embodiment, the audio signal which needs to be gained is delayed for a certain time and then gained. The difference between delayed and non-delayed gain is that in the delayed case the gain will start to drop before the output signal is expected to exceed the guard threshold. Preferably, the first preset time ranges from 1ms to 15 ms.
Fig. 10 is a schematic diagram of a second flow of a speaker signal protection method according to an embodiment of the present invention, where based on the speaker signal protection apparatus according to the embodiment of the present invention, the speaker signal protection method according to the embodiment of the present invention further includes:
100, acquiring a root mean square or a mean square value of a second audio signal to be processed in a first preset time window; the second audio signal to be processed is an audio signal obtained by performing gain on the first audio signal to be processed;
101, acquiring a second target gain value according to the root mean square or the mean square value and a corresponding threshold value determined by the rated power of the target loudspeaker;
and 102, performing gain on the second audio signal to be processed according to the second target gain value, and then outputting the second audio signal to be processed.
It should be noted that the method described in this embodiment may be implemented by the fifth structure of the speaker signal protection device shown in fig. 5, or the sixth structure of the speaker signal protection device shown in fig. 6, that is, implemented by the temperature protection module, where specific steps 100, 101, and 102 are executed by the temperature protection module.
The audio signal output by the previous signal protection module, i.e. the second audio signal to be processed, is input into the temperature protection module shown in fig. 7 in two paths, wherein one path of signal is directly input into the booster, which is a signal for gain output, and the other path of signal is processed by the second detector and the gain calculator and then input into the booster.
In step 100, a root mean square or a mean square value of a first audio signal to be processed in a first preset time window is obtained through a second detector; the length of the first preset time window may be adjusted according to the actual application, which is not limited in the embodiment of the present invention. For example, in some applications, the length of the first preset time window may range between 10ms and 1 s.
In step 101, the gain calculator compares the root mean square or the mean square value obtained by the second detector with a threshold determined by the rated power of the target loudspeaker to obtain a first target gain value at which the average output power of the audio signal in a first preset time window does not exceed the rated power of the target loudspeaker, and outputs the first target gain value to the gain unit for gain.
In step 102, the gain calculator gains the audio signal input by the main link according to the first target gain value obtained by the gain calculator. Specifically, the audio signal input by the main link is multiplied by the first target gain value and then output.
According to the embodiment of the invention, gain calculation is carried out according to the root mean square or mean square value of the input audio signal and the threshold value determined by the rated power of the target loudspeaker, the gain value required by temperature protection is obtained, and gain is carried out through the gain device, so that the temperature protection of the target loudspeaker is realized. According to the embodiment of the invention, the root mean square or mean square value of the audio signal to be processed in a certain time window is monitored in real time by the second detector, and the gain on a signal chain is reduced before, when or after the root mean square or mean square value exceeds a threshold value determined by the rated power of a target loudspeaker, so that the temperature of a loudspeaker coil does not need to be actually estimated, and the temperature protection of the loudspeaker can be realized without measuring the voltage and the current on the loudspeaker coil in real time.
Based on the above embodiment, in step 102, the step of performing gain output on the second audio signal to be processed according to the second target gain value further includes:
and smoothing the second target gain value, and taking the smoothed result as the second target gain value.
In this embodiment, a value obtained by smoothing the calculated gain value is used as the target gain value.
Based on the foregoing embodiment, in step 102, the performing gain on the second audio signal to be processed according to the second target gain value and outputting the second audio signal after the gain is performed specifically includes:
delaying the second audio signal to be processed for a second preset time;
and according to the second target gain value, the delayed second audio signal to be processed is output after being gained.
It should be noted that the method described in this embodiment may be implemented by the second structure of the temperature protection module shown in fig. 8.
In the foregoing embodiment, the input audio signal is directly subjected to gain without delay; in the embodiment, the audio signal which needs to be gained is delayed for a certain time and then gained. The difference between delayed and non-delayed gain is that in the delayed case the gain will start to drop before the expected power exceeds the threshold. Preferably, the second preset time ranges from 1ms to 15 ms.
It should be noted that, in the loudspeaker signal protection methods provided in all embodiments of the present invention, if the processed finally output audio signal is further subjected to other linear processing before entering the loudspeaker, for example, filtering through a high-pass filter, etc., a linear processing completely identical to the linear processing may be added to the link where the gain calculator of the first signal protection module is located, for example, a high-pass filter is added, and the signals before and after the linear processing are respectively introduced to the subsequent modules on the link where the gain calculator of the first signal protection module is located, so that the gain control is in accordance with the final actual requirement, and the actual requirement is met.
In summary, embodiments of the present invention provide a speaker signal protection apparatus and a speaker signal protection method based on the speaker signal protection apparatus, in terms of signal protection, the embodiments of the present invention perform signal gain control in a feedforward manner to ensure that signal truncation distortion does not occur; in terms of temperature protection, the embodiment of the invention monitors the root mean square or mean square value of the input signal of the loudspeaker in a certain time window in real time, and reduces the gain on a signal chain before, during or after the root mean square or mean square value exceeds the threshold corresponding to the rated power of the loudspeaker, without actually estimating the temperature of a loudspeaker coil, thereby measuring the voltage and the current on the loudspeaker coil in real time. Compared with the prior art based on real-time measurement of the voltage and the current on the loudspeaker coil, the embodiment of the invention can achieve the same protection and playback effects by obviously lower software and hardware expenses; compared with the prior art based on the amplitude of the input signal of the loudspeaker, the embodiment of the invention can achieve a better playback effect while proving a more reliable protection effect.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (12)
1. A loudspeaker signal protection device, comprising: one or more signal protection modules connected in sequence; the input end of the signal protection module is used for receiving a first audio signal to be processed or is connected with the signal protection module connected in front, and the output end of the signal protection module is connected with the signal protection module connected in back or outputs the processed audio signal;
the signal protection module comprises a first gain device and a first gain calculator;
the input end of the first gain calculator is used for receiving a first audio signal to be processed, and the output end of the first gain calculator is connected with the input end of the first gain calculator;
the input end of the first booster is also used for receiving a first audio signal to be processed, and the output end of the first booster is connected with a signal protection module connected behind or outputs the processed first audio signal;
the first gain calculator is used for comparing an instantaneous value of the first audio signal to be processed with a rated maximum voltage of a current signal link to obtain a first target gain value;
and the first gain device is used for gaining the first audio signal to be processed according to the first target gain value and outputting the gained first audio signal.
2. The apparatus of claim 1, wherein the signal protection module further comprises a first peak detector;
the input end of the first peak detector is used for receiving a first audio signal to be processed, and the output end of the first peak detector is connected with the input end of the first gain calculator.
3. The apparatus of claim 1, wherein the signal protection module further comprises a first delay;
the input end of the first delayer is used for receiving the first audio signal to be processed, and the output end of the first delayer is connected with the input end of the first booster.
4. The apparatus of claim 2, wherein the signal protection module further comprises a first delay;
the input end of the first delayer is used for receiving the first audio signal to be processed, and the output end of the first delayer is connected with the input end of the first booster.
5. The device according to any one of claims 1-4, further comprising a temperature protection module; the input end of the temperature protection module is connected with any signal protection module, and the output end of the temperature protection module is connected with a subsequent signal protection module or used for outputting a processed audio signal;
the temperature protection module comprises a second detector, a second gain calculator and a second gain device;
the second detector is a root-mean-square detector or a mean-square detector, the input end of the second detector is used for receiving a second audio signal to be processed, and the output end of the second detector is connected with the input end of the second gain calculator; the second audio signal to be processed is an audio signal output by a previous signal protection module;
the output end of the second gain calculator is connected with the input end of the second gain calculator;
the input end of the second booster is also used for receiving the second audio signal to be processed, and the output end of the second booster is used for outputting the processed second audio signal.
6. The apparatus of claim 5, wherein the temperature protection module further comprises a second delay;
the input end of the second delayer is used for receiving the second audio signal to be processed, and the output end of the second delayer is connected with the input end of the second booster.
7. A loudspeaker signal protection method based on the loudspeaker signal protection device of any one of claims 1-6, comprising:
acquiring a first target gain value according to an instantaneous value or a peak value of a first audio signal to be processed and a rated maximum voltage of a current signal link;
and performing gain on the first audio signal to be processed according to the first target gain value and outputting the first audio signal to be processed.
8. The method of claim 7, wherein the gain-outputting the first audio signal to be processed according to the first target gain value further comprises:
and smoothing the first target gain value, and taking the smoothed result as the first target gain value.
9. The method according to claim 7 or 8, wherein the outputting the first audio signal to be processed after the gain is performed on the first audio signal to be processed according to the first target gain value specifically comprises:
delaying the first audio signal to be processed for a first preset time;
and the delayed first audio signal to be processed is output after being gained according to the first target gain value.
10. The method of claim 7, further comprising:
acquiring a root mean square or a mean square value of a second audio signal to be processed in a first preset time window; the second audio signal to be processed is an audio signal obtained by performing gain on the first audio signal to be processed;
acquiring a second target gain value according to the root mean square or the mean square value and a corresponding threshold value determined by the rated power of the target loudspeaker;
and performing gain on the second audio signal to be processed according to the second target gain value and outputting the second audio signal to be processed.
11. The method according to claim 10, wherein the step of performing the post-gain output on the second audio signal to be processed according to the second target gain value further comprises:
and smoothing the second target gain value, and taking the smoothed result as the second target gain value.
12. The method according to claim 10 or 11, wherein the outputting the second audio signal to be processed after the gain is performed on the second audio signal to be processed according to the second target gain value specifically comprises:
delaying the second audio signal to be processed for a second preset time;
and according to the second target gain value, the delayed second audio signal to be processed is output after being gained.
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