WO2017107392A1 - Method and system for reproducing low-frequency signals - Google Patents

Abstract

The present invention discloses a method for reproducing low-frequency signals, comprising: performing low-frequency filtering on inputted audio signals to obtain low-frequency audio signals from the audio signals; performing frequency mixing on the obtained low-frequency audio signals and preset high-frequency signals, so as to modulate the low-frequency signals with the preset high-frequency signals to form mixed-frequency signals, wherein the preset high-frequency signals are of a frequency higher than a highest frequency perceivable by human ears; outputting the mixed-frequency signals and the original audio signals, or outputting the mixed-frequency signals and high-frequency audio signals obtained by subjecting the audio signals to high-frequency filtering. The present invention also discloses a system for reproducing low-frequency signals. The present invention solves the problem of small speakers being unable to reproduce low-frequency signals.

Description

 Low frequency signal reproduction method and system

Technical field

The present invention relates to the field of audio signal technologies, and in particular, to a method and system for reproducing low frequency signals.

Background technique

At present, the internal speakers of mobile phones, tablet computers, flat-panel TVs and other terminals on the market are small in size, and the intermediate frequency and high-frequency signals can only be reproduced for the input full-band audio signals, and for low-frequency signals, The structure and space limitations of the speaker itself, for example, the high characteristic frequency of the speaker itself, the bandwidth of the sound pressure curve cannot be extended to the low frequency, and the terminals with small speaker sizes cannot reproduce the low frequency signal.

Summary of the invention

The invention provides a low frequency signal reproducing method and system, the main purpose of which is to solve the problem that a small size speaker cannot reproduce a low frequency signal.

To achieve the above object, the present invention provides a low frequency signal reproduction method, and the low frequency signal reproduction method includes:

Performing low-frequency filtering processing on the input audio signal to acquire a low-band audio signal in the audio signal;

Mixing the obtained low-band audio signal with a preset high-frequency signal to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where the preset high The frequency of the frequency signal is greater than the highest frequency that can be heard by the human ear;

The amplitude control of the acquired low-band audio signal is performed according to a speaker parameter of a device that outputs the mixed signal;

Mixing the amplitude-controlled low-band audio signal with a preset high-frequency signal;

Performing high frequency filtering processing on the input audio signal to obtain a high frequency band audio signal in the audio signal, wherein the low cutoff frequency for performing high frequency filtering processing on the input audio signal is equal to the audio signal High cutoff frequency for low frequency filtering;

Outputting the mixed signal through a speaker while outputting the original audio signal through a speaker other than the speaker, or adding the formed mixed signal to the acquired high-band audio signal, and outputting an overlay The subsequent mixing signal and the high frequency audio signal.

Preferably, the step of performing the mixing processing of the amplitude-adjusted low-band audio signal and the preset high-frequency signal comprises:

And amplitude-adjusting the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive;

The low-band audio signal after the amplitude offset is mixed with the preset high-frequency signal.

To achieve the above object, the present invention provides a low frequency signal reproduction method, and the low frequency signal reproduction method includes:

Performing low-frequency filtering processing on the input audio signal to acquire a low-band audio signal in the audio signal;

Mixing the obtained low-band audio signal with a preset high-frequency signal to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where the preset high The frequency of the frequency signal is greater than the highest frequency that can be heard by the human ear;

Outputting the mixed signal and the original audio signal, or outputting the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.

Preferably, before the step of outputting the mixed signal and the high frequency signal obtained by the high frequency filtering of the audio signal, the low frequency signal reproducing method further comprises the steps of:

Performing high frequency filtering processing on the input audio signal to obtain a high frequency band audio signal in the audio signal, wherein the low cutoff frequency of performing high frequency filtering processing on the input audio signal is equal to the opposite The high cutoff frequency of the audio signal subjected to low frequency filtering processing;

The step of outputting the mixed signal and the high frequency signal obtained by the high frequency filtering of the audio signal includes:

And adding the formed mixed frequency signal to the acquired high frequency band audio signal, and outputting the superposed mixed frequency signal and the high frequency band audio signal.

Preferably, the step of mixing the acquired low-band audio signal with a preset high-frequency signal to modulate the low-band signal on the preset high-frequency signal to form a mixed-frequency signal includes: :

And performing amplitude control on the acquired low-band audio signal according to a speaker parameter of a device that outputs the mixed signal;

The amplitude-controlled low-band audio signal is mixed with the preset high-frequency signal.

Preferably, the step of adding the formed mixing signal to the acquired high-band audio signal and outputting the superimposed mixed signal and the high-band audio signal comprises:

After the formed mixed signal is added to the acquired high-band audio signal and amplified by the power amplifier, the speaker is driven to output the superimposed mixed signal and the high-band audio signal.

Preferably, the step of performing the mixing processing of the amplitude-adjusted low-band audio signal and the preset high-frequency signal comprises:

And amplitude-adjusting the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive;

The low-band audio signal after the amplitude offset is mixed with the preset high-frequency signal.

Preferably, the step of outputting the mixing signal and the original audio signal comprises:

The mixed signal is output through a speaker while the original audio signal is output through a speaker other than the speaker.

In addition, to achieve the above object, the present invention also provides a low frequency signal reproduction system, the low frequency signal reproduction system comprising:

a first filtering module, configured to perform low-frequency filtering processing on the input audio signal, and acquire a low-band audio signal in the audio signal;

a mixing module, configured to perform mixing processing on the acquired low-band audio signal and a preset high-frequency signal, to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where The frequency of the preset high frequency signal is greater than the highest frequency that can be heard by the human ear;

And an output module, configured to output the mixed signal and the original audio signal, or output the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.

Preferably, the low frequency signal reproduction system further comprises:

a second filtering module, configured to perform high frequency filtering processing on the input audio signal, to acquire a high frequency band audio signal in the audio signal, wherein the input of the audio signal is low in high frequency filtering processing a cutoff frequency equal to a high cutoff frequency for low frequency filtering of the audio signal;

The output module includes:

a signal superimposing unit, configured to add the formed mixing signal to the acquired high-band audio signal;

And a signal output unit, configured to output the superimposed mixed signal and the high frequency audio signal.

Preferably, the mixing module comprises:

An amplitude adjustment unit, configured to perform amplitude control on the acquired low-band audio signal according to a speaker parameter of a device that outputs the mixed signal;

And a signal modulating unit, configured to perform mixing processing on the amplitude-controlled low-band audio signal and the preset high-frequency signal.

Preferably, the output module is further configured to add the formed mixing signal to the acquired high-band audio signal and amplify the power amplifier, and then drive the speaker to output the superimposed mixed signal. And the high frequency audio signal.

Preferably, the signal modulating unit is further configured to perform amplitude offset on the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive; and after being amplitude-biased The low frequency audio signal is mixed with the preset high frequency signal.

Preferably, the step of outputting the mixing signal and the original audio signal comprises:

The mixed signal is output through a speaker while the original audio signal is output through a speaker other than the speaker.

The low frequency signal reproducing method and system proposed by the invention filter the input audio signal to obtain a low frequency audio signal in the audio signal, and mix the low frequency audio signal with a preset high frequency signal, wherein The frequency value of the high frequency signal is greater than the highest frequency that can be heard by the human ear to modulate the low frequency audio signal on the preset high frequency signal, so that the amplitude of the preset high frequency signal follows the low frequency audio signal. The change is changed, and the small-sized speaker can reproduce the preset high-frequency signal, and the human ear can perceive the low-band audio signal modulated on the preset high-frequency signal, thereby solving the problem that the small-sized speaker cannot reproduce the low-frequency signal. problem.

DRAWINGS

1 is a flow chart of a first embodiment of a low frequency signal reproduction method according to the present invention;

2 is a schematic flowchart of a refinement step of a mixing step in a second embodiment of a low frequency signal reproducing method according to the present invention;

3 is a schematic flowchart of adding a low-band audio signal and a high-band audio signal in a second embodiment of the low-frequency signal reproducing method according to the present invention;

4 is a schematic diagram of a mixing process in a second embodiment of the low frequency signal reproducing system of the present invention;

5 is a schematic diagram of functional modules of a first embodiment of a low frequency signal reproduction system according to the present invention;

6 is a schematic diagram of a refinement function module of a mixing module in a second embodiment of the low frequency signal reproducing system of the present invention.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a low frequency signal reproduction method.

Referring to Figure 1, there is shown a flow chart of a first embodiment of a low frequency signal reproduction method of the present invention.

In the first embodiment, the low frequency signal reproduction method includes:

Step S10, performing low frequency filtering processing on the input audio signal to acquire a low frequency band audio signal in the audio signal;

The audio signal may include signals of various frequency bands. In this embodiment, the low-band audio signal in the input audio signal needs to be processed for processing, so that the human ear can feel the existence of the low-frequency signal, so it is necessary to filter out first. The low-band audio signal in the input audio signal is subjected to low-frequency filtering processing on the input audio signal to obtain a low-band audio signal, which can be implemented by a filter. For example, a low-pass filter can be used, and the cutoff frequency f2 can be set to enable the input. In the audio signal, the frequency signal with frequency lower than f2 is almost not attenuated, and the frequency signal higher than f2 in the audio signal is greatly attenuated by ground; or the band pass filter is used, the user can set the frequency of a low frequency band. The interval (f1, f2) is used as a pass band, so that a frequency signal having a frequency higher than f1 and lower than f2 in the input audio signal is hardly attenuated to obtain a low-band audio signal in the input audio signal, The setting of the frequency value of the filter can be set by the user according to the characteristics of the speaker and the low frequency band that needs to be reproduced. Set, in the present preferred embodiment, bandpass filter to filter, wherein the cutoff value of the low frequency f1 is preferably 20-30 Hz, the cutoff value of the high frequency f2 is preferably 100-140 Hz.

Step S20, performing the mixing process on the acquired low-band audio signal and the preset high-frequency signal, to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where The frequency of the preset high frequency signal is greater than the highest frequency that can be heard by the human ear;

Step S30, outputting the mixed signal and the original audio signal, or outputting the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.

Introducing a preset high frequency signal, mixing the obtained low frequency band audio signal with a preset high frequency signal, and multiplying the obtained low frequency band audio signal by a preset high frequency signal to achieve the obtained The low-band audio signal modulation forms a mixed signal on the introduced preset high-frequency signal, and the preset high-frequency signal is introduced as a carrier, and the amplitude of the preset high-frequency signal changes with the change of the low-band audio signal. It should be noted that the frequency of the above-mentioned preset high-frequency signal is greater than the highest frequency that can be heard by the human ear, since the frequency range that the human ear can perceive is 20 Hz-20 KHz, but, in general, when the frequency of the audio signal When the value is greater than 16 kHz, the human ear sensitivity is substantially not heard by the signal. Therefore, the frequency of the preset high frequency signal in this embodiment is greater than 16 kHz, that is, outside the frequency range that can be heard by the human ear. After obtaining the above mixing signal, the mixing signal is output. For example, the mixing signal can be sent to the power amplifier to amplify the driving speaker for output, since the preset high frequency signal can be reproduced by the small-sized speaker, because the human ear is The response to acoustic energy is non-linear. This nonlinearity produces additional overtones and intermodulation distortions in the form of harmonics during the auditory action, which does not exist in the actual input original audio signal. These nonlinear effects are very noticeable for low frequency signals, and these effects have a significant effect on the way the low frequency sound is perceived, so that the human ear can perceive the low frequency envelope (the beat principle) modulated on the high frequency signal, thereby generating a low frequency. The feeling of sound.

Further, since there may be no low-band audio signal in the input audio signal, after filtering through the filter, the low-band audio signal may not be obtained or the obtained low-band audio signal is very weak and negligible. The frequency band of the input audio signal is mainly located in the high frequency band, and the frequency value thereof is greater than the high cutoff frequency f2, so that the low frequency signal reproduction processing of the audio signal is not required.

Regarding the processing of the high-band audio signal in the input audio signal, there may be various implementation manners. Two embodiments are listed below. In the first mode, after the mixing signal is obtained, the speaker can directly output the audio signal. Mixing the signal, and simultaneously playing the input original audio signal through other speakers, and secondly, superimposing the input original audio signal and the mixed signal, and outputting the method, the specific embodiment is: before step S30, the low frequency signal reproducing method Also includes the steps:

And performing high frequency filtering processing on the input audio signal to obtain a high frequency band audio signal in the audio signal, wherein the low cutoff frequency of performing high frequency filtering processing on the input audio signal is equal to the audio The signal performs a high cutoff frequency of the low frequency filtering process; the step S30 includes: adding the formed mixed signal to the acquired high frequency band audio signal, and outputting the superposed mixed frequency signal and the high frequency band audio signal .

In this embodiment, in order to make the finally outputted audio signal have a good sound effect, the input audio signal is filtered by a filter to obtain a high-band audio signal in the original audio signal, for example, can be set by a high-pass filter. The high-pass filter has a low cutoff frequency of f3, preferably f3=f2, or is filtered by a bandpass filter with a high cutoff frequency set to f4 and a passband of (f3, f4) so that the input audio signal can be made The frequency signal with a medium frequency higher than f3 and lower than f4 is hardly attenuated to obtain a high-band audio signal in the input audio signal, and after the above-mentioned mixed signal, the mixed signal is filtered and obtained. The high-band audio signals are added and outputted. Specifically, the formed mixed signal is added to the acquired high-band audio signal and amplified by the power amplifier, and the mixed output of the speaker output is driven. Frequency signal and the high frequency audio signal. Since the audio signal generally exceeds 16KHz, the human ear is basically inaudible, and for a general speaker, it can emit 15KHz-20 The signal of KHz, therefore, preferably, in the present embodiment, the value of f4 is preferably 14-16 KHz.

Further, in the embodiment, a single-frequency high-frequency signal is introduced as a preset high-frequency signal, and the single-frequency high-frequency signal is used as a carrier as a carrier with respect to a high-frequency signal with multiple frequency bands, so that a better mixing effect can be obtained. Preferably, the frequency value of the single-frequency high-frequency signal is greater than f4, preferably, 17KHz-18 KHz, for example, takes 17 kHz.

The low-frequency signal reproducing method proposed in this embodiment performs filtering processing on the input audio signal to obtain a low-band audio signal in the audio signal, and mixes the low-band audio signal with a preset high-frequency signal, where The frequency value of the high frequency signal is greater than the highest frequency that can be heard by the human ear to modulate the low frequency audio signal on the preset high frequency signal, so that the amplitude of the preset high frequency signal changes with the audio signal of the low frequency band. And the change, while the small-sized speaker can reproduce the preset high-frequency signal, the human ear can perceive the low-band audio signal modulated on the preset high-frequency signal, thereby solving the problem that the small-sized speaker cannot reproduce the low-frequency signal. .

Referring to Fig. 2, a second embodiment of the low frequency signal reproducing method of the present invention is proposed based on the first embodiment of the low frequency signal reproducing method of the present invention. In this embodiment, the method differs from the first embodiment in that step S20 includes the following refinement steps:

Step S21, performing amplitude control on the acquired low-band audio signal according to the speaker parameter of the device that outputs the mixed signal;

Step S22, mixing the amplitude-controlled low-band audio signal with the preset high-frequency signal.

Referring to FIG. 3, in the embodiment, in order to balance the high-frequency and low-frequency signal amplitudes after the filtered high-band audio signal and the mixed-frequency signal are added, the low-band signal obtained by filtering is first used before the mixing process. Amplitude adjustment, for example, the amplitude of the audio signal can be controlled by a digital resistance attenuator, or the amplitude of the low-band audio signal obtained by automatic gain control. The automatic gain control is a type of limiting output, which utilizes linear amplification and compression amplification. The effective combination adjusts the output signal of the hearing aid. When the weak signal is input, the linear amplifying circuit works to ensure the intensity of the output signal. When the input signal reaches a certain intensity, the compression amplifying circuit is activated to reduce the output amplitude.

Further, step S22 includes:

And amplitude-adjusting the amplitude-adjusted low-band audio signal, so that the amplitude value of the low-band audio signal is positive; the low-band audio signal after being amplitude-biased and the preset high-frequency signal Perform mixing processing.

If the amplitude-adjusted low-band audio signal is directly mixed with the preset high-frequency signal, or the low-band audio signal directly obtained by the filtering is directly mixed with the preset high-frequency signal, although the human ear can feel To the low-band audio signal in the mixed signal, but the frequency value of the obtained mixed signal is different from the frequency value of the low-band audio signal. For example, the frequency value of the mixed signal may be only the frequency value of the low-band audio signal. Half, therefore, in order to ensure that the frequency value of the output mixed signal is equal to the frequency value of the low-band audio signal before mixing, the signal amplitude offset processing is performed on the amplitude-adjusted low-band audio signal before the mixing process, The amplitude values of the low-band audio signals are all positive; as shown in FIG. 4, the amplitudes of the low-band audio signals after the offset processing are positive values, and the obtained frequency of the mixed signals is adjusted after the amplitude adjustment. The frequency values of the low-band audio signals are the same.

The low frequency signal reproducing method proposed in this embodiment performs amplitude control and/or amplitude offset processing on the audio signal of the low frequency band before mixing, thereby further improving the sound quality effect of the obtained mixed frequency signal.

The invention also proposes a low frequency signal reproduction system.

Referring to FIG. 5, it is a schematic diagram of functional modules of the first embodiment of the low frequency signal reproduction system of the present invention.

In this embodiment, the low frequency signal reproduction system comprises:

The first filtering module 10 is configured to perform low-frequency filtering processing on the input audio signal to acquire a low-band audio signal in the audio signal;

The audio signal may include signals of various frequency bands. In this embodiment, the low-band audio signal in the input audio signal needs to be processed for processing, so that the human ear can feel the existence of the low-frequency signal, so it is necessary to filter out first. The low-band audio signal in the input audio signal is subjected to low-frequency filtering processing on the input audio signal to obtain a low-band audio signal, which can be implemented by a filter. For example, a low-pass filter can be used, and the cutoff frequency f2 can be set to enable the input. In the audio signal, the frequency signal with frequency lower than f2 is almost not attenuated, and the frequency signal higher than f2 in the audio signal is greatly attenuated by ground; or the band pass filter is used, the user can set the frequency of a low frequency band. The interval (f1, f2) is used as a pass band, so that a frequency signal having a frequency higher than f1 and lower than f2 in the input audio signal is hardly attenuated to obtain a low-band audio signal in the input audio signal, that is, The first filtering module 10 may be a low pass filter or a band pass filter, etc., regarding the setting of the frequency value of the filter The user can be set according to the characteristics of the speaker and the low frequency band that needs to be reproduced. In the embodiment, the band pass filter is preferably used for filtering, wherein the value of the low cutoff frequency f1 is preferably 20-30 Hz, and the high cutoff The value of the frequency f2 is preferably 100-140 Hz.

The mixing module 20 is configured to perform mixing processing on the acquired low-band audio signal and a preset high-frequency signal, to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, Wherein the frequency of the preset high frequency signal is greater than the highest frequency that can be heard by the human ear;

The output module 30 is configured to output the mixed signal and the original audio signal, or output the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.

Introducing a preset high frequency signal, the mixing module 20 performs mixing processing on the obtained low frequency band audio signal and the preset high frequency signal, and multiplies the obtained low frequency band audio signal by the preset high frequency signal to realize The obtained low-band audio signal is modulated on the introduced preset high-frequency signal to form a mixed signal, and the preset high-frequency signal is introduced as a carrier, and the amplitude of the preset high-frequency signal follows the low-band audio signal. The change of the change, need to be explained, the frequency of the above-mentioned preset high-frequency signal is greater than the highest frequency that the human ear can hear, because the human ear can perceive the frequency range of 20Hz-20KHz, but, in general, when When the frequency value of the audio signal is greater than 16 kHz, the human ear can hardly hear the signal. Therefore, the frequency of the preset high frequency signal in this embodiment is greater than 16 kHz, that is, outside the frequency range that can be heard by the human ear. After obtaining the above mixing signal, the output module 30 outputs the mixed signal, for example, the mixing signal can be sent to the power amplifier to amplify the driving speaker to output the audio signal, since the preset high frequency signal can be weighted by a small-sized speaker. Now, since the human ear is non-linear in response to acoustic energy, this nonlinearity produces additional overtones and intermodulation distortions in the form of harmonics during the auditory action, which does not exist in the actual input original audio signal. These non-linear effects are very noticeable for low frequency signals, and these effects have a significant effect on the way the low frequency sound is perceived, so that the human ear can perceive the low frequency envelope modulated at the high frequency signal, thereby producing a low frequency sound.

Further, since there may be no audio signal of the low frequency band in the input audio signal, after filtering by the first filtering module 10, the low frequency audio signal may not be obtained or the obtained low frequency audio signal is very weak and negligible. At this time, it is explained that the frequency band of the input original audio signal is mainly located in the high frequency band, and the frequency value thereof is greater than the high cutoff frequency f2, so that the low frequency signal reproduction processing of the audio signal is not required.

Regarding the processing of the high-band audio signal in the input original audio signal, there may be various implementation manners. Two embodiments are listed below. In the first mode, the output module 30 can directly pass the obtained mixing signal. A separate speaker outputs the mixed signal, and at the same time, the input original audio signal is played through other speakers. In the second mode, the input original audio signal is superimposed on the mixed signal and outputted. The specific implementation manner is as follows: the low frequency signal reproduction system further include:

a second filtering module, configured to perform high frequency filtering processing on the input audio signal, to acquire a high frequency band audio signal in the audio signal, wherein the input of the audio signal is low in high frequency filtering processing a cutoff frequency equal to the high cutoff frequency of the low frequency filtering process on the audio signal;

The output module 30 includes:

a signal superimposing unit, configured to add the formed mixing signal to the acquired high-band audio signal;

And a signal output unit, configured to output the superimposed mixed signal and the high frequency audio signal.

In this embodiment, in order to make the finally outputted audio signal have a good sound effect, the input audio signal is filtered by the second filtering module to obtain a high-band audio signal in the original audio signal. For example, the second filtering module may Is a high-pass filter, set the lower cutoff frequency of the high-pass filter to f3, preferably, f3=f2, or the second filter module can also be a band-pass filter, the lower cutoff frequency is set to f3, and the upper cutoff frequency is set to f4 The passband is (f3, f4), so that the second filtering module can make the frequency signal of the input audio signal higher than f3 and lower than f4 pass through the attenuation almost without attenuation, to obtain the input audio signal. After the high frequency band audio signal is added to the mixed frequency signal, the mixed frequency signal is added to the filtered high frequency band audio signal, and specifically, the formed mixed signal and the obtained high frequency band audio are obtained. After the signals are added and amplified by the power amplifier, the speaker is driven to output the superimposed mixed signal and the high-band audio signal. Since the audio signal generally exceeds 16KHz, the human ear is basically inaudible, and for a general speaker, it can emit 16KHz-20 The signal of KHz, therefore, preferably, in the present embodiment, the value of f4 is preferably 14-16 KHz.

Further, in the embodiment, a single-frequency high-frequency signal is introduced as a preset high-frequency signal, and the single-frequency high-frequency signal is used as a carrier as a carrier with respect to a high-frequency signal with multiple frequency bands, so that a better mixing effect can be obtained. Preferably, the frequency value of the single-frequency high-frequency signal is greater than f4, preferably, 17KHz-18 KHz, for example, takes 17 kHz.

The low frequency signal reproducing system proposed in this embodiment filters the input audio signal to obtain a low frequency audio signal in the audio signal, and mixes the low frequency audio signal with a preset high frequency signal, where The frequency value of the high frequency signal is greater than the highest frequency that can be heard by the human ear to modulate the low frequency audio signal on the preset high frequency signal, so that the amplitude of the preset high frequency signal changes with the audio signal of the low frequency band. And the change, while the small-sized speaker can reproduce the preset high-frequency signal, the human ear can perceive the low-band audio signal modulated on the preset high-frequency signal, thereby solving the problem that the small-sized speaker cannot reproduce the low-frequency signal. .

Referring to Figure 6, a second embodiment of the low frequency signal reproduction system of the present invention is presented based on a first embodiment of the low frequency signal reproduction system of the present invention. In this embodiment, the system differs from the first embodiment in that the mixing module 20 includes the following units:

The amplitude adjustment unit 21 is configured to perform amplitude control on the acquired low-band audio signal according to the speaker parameter of the device that outputs the mixed signal;

The signal modulating unit 22 is configured to perform mixing processing on the amplitude-controlled low-band audio signal and the preset high-frequency signal.

Referring to FIG. 3, in the embodiment, in order to equalize the amplitudes of the high and low frequency signals after the filtered high frequency audio signal and the mixed signal are added, the amplitude adjusting unit 21 firstly filters the filtering before the mixing processing. The low-band signal is amplitude-adjusted. For example, the amplitude of the audio signal can be controlled by a digital resistor attenuator, or the amplitude of the low-band audio signal obtained by automatic gain control. The automatic gain control is a type of limiting output, which utilizes linearity. The effective combination of amplification and compression amplification adjusts the output signal of the hearing aid. When the weak signal is input, the linear amplifying circuit works to ensure the intensity of the output signal. When the input signal reaches a certain intensity, the compression amplifying circuit is activated to reduce the output amplitude.

Further, the signal modulating unit 22 is further configured to perform amplitude offset on the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive; The low frequency audio signal is mixed with the preset high frequency signal.

If the signal modulation unit 22 directly mixes the amplitude-adjusted low-band audio signal with the preset high-frequency signal, or directly mixes the low-band audio signal directly obtained by the filtering with the preset high-frequency signal, although The human ear can feel the low-band audio signal in the mixed signal, but the frequency value of the obtained mixed signal is different from the frequency value of the low-band audio signal. For example, the frequency value of the mixed signal may be only the low-band audio signal. Half of the frequency value, therefore, in order to ensure that the frequency value of the output mixed signal is equal to the frequency value of the low-band audio signal before mixing, the signal modulating unit 22 pairs the amplitude-adjusted low-band audio before the mixing process. The signal is subjected to signal amplitude offset processing such that the amplitude values of the low-band audio signals are positive; as shown in FIG. 4, the amplitudes of the low-band audio signals subjected to the bias processing by the signal modulation unit 22 are all positive values. The frequency of the mixed signal is consistent with the frequency value of the amplitude-adjusted low-band audio signal.

The low frequency signal reproducing system proposed in this embodiment performs amplitude control and/or amplitude offset processing on the audio signal of the low frequency band before mixing, thereby further improving the sound quality effect of the obtained mixed frequency signal.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the present invention and the drawings are directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims (18)

1. A low frequency signal reproducing method, characterized in that the low frequency signal reproducing method comprises:

   Performing low-frequency filtering processing on the input audio signal to acquire a low-band audio signal in the audio signal;

   Mixing the obtained low-band audio signal with a preset high-frequency signal to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where the preset high The frequency of the frequency signal is greater than the highest frequency that can be heard by the human ear;

   The amplitude control of the acquired low-band audio signal is performed according to a speaker parameter of a device that outputs the mixed signal;

   Mixing the amplitude-controlled low-band audio signal with a preset high-frequency signal;

   Performing high frequency filtering processing on the input audio signal to obtain a high frequency band audio signal in the audio signal, wherein the low cutoff frequency for performing high frequency filtering processing on the input audio signal is equal to the audio signal High cutoff frequency for low frequency filtering;

   Outputting the mixed signal through a speaker while outputting the original audio signal through a speaker other than the speaker, or adding the formed mixed signal to the acquired high-band audio signal, and outputting an overlay The subsequent mixing signal and the high frequency audio signal.
2. The low frequency signal reproducing method according to claim 1, wherein the step of mixing the amplitude-adjusted low-band audio signal with the preset high-frequency signal comprises:

   And amplitude-adjusting the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive;

   The low-band audio signal after the amplitude offset is mixed with the preset high-frequency signal.
3. A low frequency signal reproducing method, characterized in that the low frequency signal reproducing method comprises:

   Performing low-frequency filtering processing on the input audio signal to acquire a low-band audio signal in the audio signal;

   Mixing the obtained low-band audio signal with a preset high-frequency signal to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where the preset high The frequency of the frequency signal is greater than the highest frequency that can be heard by the human ear;

   Outputting the mixed signal and the original audio signal, or outputting the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.
4. The low frequency signal reproducing method according to claim 3, wherein said low frequency signal reproducing method is performed before said step of outputting said mixed frequency signal and said high frequency signal obtained by high frequency filtering of said audio signal Also includes the steps:

   Performing high frequency filtering processing on the input audio signal to obtain a high frequency band audio signal in the audio signal, wherein the low cutoff frequency for performing high frequency filtering processing on the input audio signal is equal to the audio signal High cutoff frequency for low frequency filtering;

   The step of outputting the mixed signal and the high frequency signal obtained by the high frequency filtering of the audio signal includes:

   And adding the formed mixed frequency signal to the acquired high frequency band audio signal, and outputting the superposed mixed frequency signal and the high frequency band audio signal.
5. The low frequency signal reproducing method according to claim 4, wherein the obtained low frequency band audio signal is mixed with a preset high frequency signal to modulate the low frequency band signal in the The steps of forming a mixed signal on the preset high frequency signal include:

   And performing amplitude control on the acquired low-band audio signal according to a speaker parameter of a device that outputs the mixed signal;

   The amplitude-controlled low-band audio signal is mixed with the preset high-frequency signal.
6. The low frequency signal reproducing method according to claim 5, wherein said mixing signal is added to said acquired high frequency band audio signal, and said superimposed said mixed frequency signal and said The steps of the high frequency audio signal include:

   After the formed mixed signal is added to the acquired high-band audio signal and amplified by the power amplifier, the speaker is driven to output the superimposed mixed signal and the high-band audio signal.
7. The low frequency signal reproducing method according to claim 5, wherein the step of mixing the amplitude-adjusted low-band audio signal with the preset high-frequency signal comprises:

   And amplitude-adjusting the amplitude-adjusted low-band audio signal, so that the amplitude values of the low-band audio signals are positive;

   The low-band audio signal after the amplitude offset is mixed with the preset high-frequency signal.
8. The low frequency signal reproducing method according to claim 4, wherein said mixing the formed mixed signal and said acquired high frequency band audio signal, and outputting said superimposed said mixed frequency signal and said The steps of the high frequency audio signal include:

   After the formed mixed signal is added to the acquired high-band audio signal and amplified by the power amplifier, the speaker is driven to output the superimposed mixed signal and the high-band audio signal.
9. The low frequency signal reproducing method according to claim 3, wherein the step of outputting the mixed signal and the original audio signal comprises:

   The mixed signal is output through a speaker while the original audio signal is output through a speaker other than the speaker.
10. The low frequency signal reproducing method according to claim 6, wherein the step of outputting the mixed signal and the original audio signal comprises:

    The mixed signal is output through a speaker while the original audio signal is output through a speaker other than the speaker.
11. A low frequency signal reproduction system, characterized in that the low frequency signal reproduction system comprises:

    a first filtering module, configured to perform low-frequency filtering processing on the input audio signal, and acquire a low-band audio signal in the audio signal;

    a mixing module, configured to perform mixing processing on the acquired low-band audio signal and a preset high-frequency signal, to modulate the low-band signal on the preset high-frequency signal to form a mixed signal, where The frequency of the preset high frequency signal is greater than the highest frequency that can be heard by the human ear;

    And an output module, configured to output the mixed signal and the original audio signal, or output the mixed signal and the high frequency audio signal obtained by the high frequency filtering of the audio signal.
12. The low frequency signal reproduction system according to claim 11, wherein the low frequency signal reproduction system further comprises:

    a second filtering module, configured to perform high frequency filtering processing on the input audio signal, to acquire a high frequency band audio signal in the audio signal, wherein the input of the audio signal is low in high frequency filtering processing a cutoff frequency equal to a high cutoff frequency for low frequency filtering of the audio signal;

    The output module includes:

    a signal superimposing unit, configured to add the formed mixing signal to the acquired high-band audio signal;

    And a signal output unit, configured to output the superimposed mixed signal and the high frequency audio signal.
13. The low frequency signal reproduction system according to claim 12, wherein the mixing module comprises:

    An amplitude adjustment unit, configured to perform amplitude control on the acquired low-band audio signal according to a speaker parameter of a device that outputs the mixed signal;

    And a signal modulating unit, configured to perform mixing processing on the amplitude-controlled low-band audio signal and the preset high-frequency signal.
14. The low frequency signal reproducing system according to claim 13, wherein the output module is further configured to add the formed mixing signal to the acquired high frequency audio signal and amplify the power amplifier. And driving the speaker to output the superimposed mixed signal and the high frequency audio signal.
15. The low frequency signal reproducing system according to claim 13, wherein the signal modulating unit is further configured to perform amplitude offset on the amplitude-adjusted low-band audio signal to enable the low-band audio signal The amplitude values are all positive; and the low-band audio signal after the amplitude offset is mixed with the preset high-frequency signal.
16. The low frequency signal reproducing system according to claim 12, wherein the output module is further configured to add the formed mixing signal to the acquired high frequency audio signal and amplify the power amplifier And driving the speaker to output the superimposed mixed signal and the high frequency audio signal.
17. The low frequency signal reproducing system according to claim 11, wherein said output module is further configured to output said mixed signal through a speaker while outputting said original audio through a speaker other than said speaker signal.
18. The low frequency signal reproducing system according to claim 14, wherein said output module is further configured to output said mixed signal through a speaker while outputting said original audio signal through a speaker other than said speaker .