CN105305991A - Compression limiter - Google Patents
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- CN105305991A CN105305991A CN201510859970.1A CN201510859970A CN105305991A CN 105305991 A CN105305991 A CN 105305991A CN 201510859970 A CN201510859970 A CN 201510859970A CN 105305991 A CN105305991 A CN 105305991A
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Abstract
The invention provides a compression limiter. The compression limiter comprises a gain adjustment module used for outputting a first output signal according to an input signal of the compression limiter, and performing feedback regulation on a first signal gain which is used for realizing the compression limiting of the input signal according to the first output signal; a sound amplification module, which is connected with the gain adjustment module and used for performing power amplification on the first output signal outputted by the gain adjustment module, and outputting a second output signal; and a clipping control module, which is respectively connected with the gain adjustment module and the sound amplification module, and used for performing feedback regulation on a second signal gain according to clipping distortion occurring in the second output signal outputted by the sound amplification module; the compression limiter performs compression limiting on the input signal according to the first signal gain and the second signal gain, and controls the second output signal outputted by the compression limiter within a limiting amplitude and outputs the second output signal. The compression limiter provided by the invention automatically eliminates the clipping distortion occurring in the second output signal, improves the output sound quality of the sound amplification module and improves the user experience.
Description
Technical field
The present invention relates to audio signal processing technique field, particularly relate to a kind of compression amplitude limiter.
Background technology
The sense of hearing dynamic range of the mankind can reach 120dB (decibel), and larger than minimum sound 1,000,000 times of the maximum acoustic that can hear.When public address equipment is at playing audio signal, make an uproar and the maximum fan-out capability (dynamic range of equipment) of public address equipment in the end being often limited to public address equipment itself, as, the end that less sound can be submerged in system, cannot be heard in making an uproar, and maximum sound can be subject to the restriction of the maximum fan-out capability of public address equipment, even there will be clipping distortion.In order to address this problem, introduce the dynamic process of voice signal, it is by reducing the dynamic range of sound, and making to amplify, establish can normal play, and compression limiting technology just belongs to a kind of technology wherein.
Compress the general principle of limiting technology generally: the entire gain first improving source of sound, the end making less sound can not be submerged in system, can be heard in making an uproar; When voice signal reaches the threshold threshold value of setting, according to the compression ratio of setting, reduce the gain of system, to reduce the dynamic range of sound; When voice signal reaches the maximum fan-out capability of system, export and no longer increase with the increase of input, prevent the clipping distortion of voice signal, in this process, the graph of a relation of the input signal of system and output signal as shown in Figure 1, in diagram, V1 is the threshold threshold value of above-mentioned setting, V2 is the magnitude of voltage that above-mentioned system reaches maximum fan-out capability, V
lfor the amplitude limit amplitude of system, and the region that the amplitude of input signal is 0 ~ V1 is linear zone, and the amplitude of input signal is the region of V1 ~ V2 is compressional zone, and the amplitude of input signal is amplitude limit district more than the region of V2.In addition, when the dynamic range of system is less, can uses and only be with the algorithm of amplitude limit function to realize above-mentioned purpose, as shown in Figure 2, V
lfor the amplitude limit amplitude of system, when the amplitude of input signal reaches V, export and no longer increase with the increase of input, corresponding with Fig. 1, the amplitude of input signal is the region of 0 ~ V is linear zone, and the amplitude of input signal is amplitude limit district more than the region of V.
In the process of compression amplitude limit, two parameters are very important, are respectively start-up time and release time.Wherein, start-up time from systems axiol-ogy to signal, exceeds threshold threshold value to the time of signal controlling in threshold threshold value; Release time is after signal diminishes, the time of the change in gain elimination of compression amplitude limit, as shown in Figure 3.As can be seen from the figure, when input signal reaches the maximum fan-out capability of system, then system reduces the gain of system according to A start-up time preset, until output signal controlled in threshold threshold value; When input signal diminishes, system increases the gain of system in right amount according to B release time preset, and increases output signal and is controlled in threshold threshold value.
But in the process of existing compression amplitude limiter start-up time, due to a variety of causes, easily there is the phenomenon of slicing truncation in output signal.As, start-up time is longer, there will be the phenomenon of slicing truncation; And for example, when there is the application conditions such as output loading becomes weight, supply voltage step-down, temperature uprise change, the dynamic range of public address equipment can reduce, and the phenomenon that now also there will be slicing truncation is waited for.System, when there is the phenomenon of slicing truncation, can produce a large amount of harmonic distortion signals thereupon, thus causes equipment sense of hearing to be deteriorated, and easily damages loud speaker.
Summary of the invention
For the problems referred to above, the present invention aims to provide a kind of compression amplitude limiter, and it eliminates the clipping distortion occurred in existing compression amplitude limiter by a clipping control module.
Technical scheme provided by the invention is as follows:
A kind of compression amplitude limiter, comprising: gain regulation module, public address module and clipping control module, wherein,
Described gain regulation module, exports the first output signal according to the input signal of described compression amplitude limiter; And according to described first output signal, feedback regulation is for realizing the first signal gain of described input signal compression amplitude limit;
Described public address module, is connected with described gain regulation module, described in amplify mould to described gain regulation module export first output signal carry out power amplification, export second output signal;
Described clipping control module, be connected with described gain regulation module and described public address module respectively, described clipping control module according to described public address module export second output signal in occur clipping distortion, feedback regulation for realize described input signal compression amplitude limit secondary signal gain;
Described compression amplitude limiter carries out compression amplitude limit according to described first signal gain and described secondary signal gain to described input signal, and the second output signal exported by described compression amplitude limiter controls to export in amplitude limit amplitude.
In the technical program, the input signal inputted system by gain regulation module is amplified, compress and amplitude limit exports the first output signal, then carry out amplification generation second by public address module to the first output signal to export, in order to eliminate the clipping distortion caused by public address module, use clipping control module to carry out feedback regulation according to the second output signal occurring clipping distortion to the gain of input signal, improve the sense of hearing of public address equipment.
Further preferably, a Gain selector is also comprised in described compression amplitude limiter, described Gain selector respectively with described gain regulation module and described clipping control model calling, described Gain selector is according to described first signal gain and the gain of described secondary signal Gain generating system signal, and described compression amplitude limiter realizes the compression amplitude limit of described input signal according to described system signal gain.
In the technical program, Gain selector is utilized to carry out selecting the yield value can eliminating the clipping distortion occurred in current system as system signal gain in the first signal gain and secondary signal gain.
Further preferably, at synchronization, described Gain selector selects less yield value as the yield value in system signal gain in described first signal gain and described secondary signal gain, and described compression amplitude limiter realizes the compression amplitude limit of described input signal according to described system signal gain.
In the technical program, Gain selector selects yield value less in the first signal gain and the second gain signal as system gain signal, thus the export second output signal is controlled in the dynamic range of public address equipment.
Further preferably, described clipping control module comprises distortion detector and the second time schedule controller, wherein,
Described distortion detector, is connected with described public address module, described distortion detector for detect described public address module export second output signal in whether there is clipping distortion;
Described second time schedule controller, be connected with described distortion detector and described Gain selector respectively, when described distortion detector detects that described second occurs clipping distortion, secondary signal gain after adjustment according to described second output signal adjustment secondary signal gain, and is inputted described Gain selector by described second time schedule controller.
In the technical program, distortion detector detects in the second output signal whether occurred clipping distortion in real time, and when having there is clipping distortion, then the second time schedule controller then adjusts secondary signal gain automatically, rapidly the amplitude that second outputs signal is controlled, in slicing amplitude, to eliminate this clipping distortion; Certainly, if not there is clipping distortion in the second output signal, then the second time schedule controller does not work (do not adjust secondary signal gain, secondary signal gain remains on original level).
Further preferably, in described second time schedule controller:
When described second occurs clipping distortion, described second time schedule controller, according to the slicing start-up time of presetting, reduces the yield value of described secondary signal gain;
When described second output signal clipping distortion is eliminated, described second time schedule controller, according to the slicing release time of presetting, increases the yield value of described secondary signal gain.
Further preferably, when described second occurs clipping distortion, described second time schedule controller, according to the slicing start-up time of presetting, reduces the yield value of described secondary signal gain; And within described slicing start-up time, the yield value of described secondary signal gain reduces the yield value that speed is greater than described first signal gain and reduces speed.
In the technical program, within slicing start-up time, the yield value of secondary signal gain reduces the yield value that speed is greater than the first signal gain and reduces speed, could elimination clipping distortion rapidly on original basis.
Further preferably, described gain regulation module comprises a variable gain amplifier, compression control amplifier, comparator and the first time schedule controller, wherein,
Described variable gain amplifier, is connected with described Gain selector, amplifies input signal according to the system signal gain that described Gain selector exports, and exports the first output signal;
Described compression control amplifier, is connected with described variable gain amplifier, according to described first output signal adjustment reference voltage;
Described comparator, is connected with described variable gain amplifier and described compression control amplifier respectively, and the amplitude of described first output signal and described reference voltage compare by described comparator;
Described first time schedule controller, is connected with described Gain selector and described comparator respectively, and described first time schedule controller adjusts the first signal gain according to the comparative result of described comparator, and the first signal gain after adjustment is inputted described Gain selector.
Further preferably, in described compression control amplifier:
When the amplitude of described first output signal is less than compression threshold threshold value, described reference voltage is drawn high by described compression control amplifier;
When the amplitude of described first output signal is between compression threshold threshold value and amplitude limit threshold threshold value, described compression controller is according to the compression ratio generating reference voltage preset;
When the amplitude of described first output signal is greater than amplitude limit threshold threshold value, described compression controller is by magnitude of voltage corresponding to described compression amplitude limiter output violent change for described reference voltage constant control.
Further preferably, in described comparator:
When the amplitude of described first output signal is greater than the reference voltage of compression control amplifier output, sends and enter instruction start-up time to described first time schedule controller;
When the amplitude of described first output signal is less than the reference voltage of compression control amplifier output, sends and enter instruction release time to described first time schedule controller.
Further preferably, in described first time schedule controller:
When entering instruction start-up time described in described first time schedule controller receives, described first time schedule controller, according to the start-up time of presetting, reduces the yield value of described first signal gain;
When entering instruction release time described in described first time schedule controller receives, described first time schedule controller, according to the release time of presetting, increases the yield value of described first signal gain;
Described start-up time much larger than described slicing start-up time.
In the technical program, start-up time is the first output signal detected beyond amplitude limit threshold threshold value to the time controlled in amplitude limit threshold threshold value; And slicing to be start-up time the second output signal occurred that clipping distortion (amplitude of the second output signal is beyond slicing amplitude) is to the time controlled in slicing amplitude.And generally, slicing amplitude is often large than amplitude limit amplitude (amplitude limit threshold threshold value and amplitude limit amplitude Cheng Ding are than relation and amplitude limit threshold threshold value is less than amplitude limit amplitude), therefore start-up time is certainly long for start-up time than slicing.We wish elimination clipping distortion as early as possible again, thus slicing often to arrange start-up time shorter, still start-up time can be long for start-up time more than slicing here.
Compression amplitude limiter provided by the invention, can bring following beneficial effect:
In the present invention, gain regulation module carries out feedback regulation according to from the first output signal exported to the first signal gain, clipping control module carries out feedback regulation according to the second output signal occurring clipping distortion to the second gain signal, and use Gain selector in the first signal gain and the second gain signal, to select to eliminate the yield value of current clipping distortion as system signal gain (selecting less yield value as system signal gain in the first signal gain and secondary signal gain), thus automatically eliminate in the second output signal because start-up time is long or weigh because output loading becomes, supply voltage step-down, the public address module reduced dynamic range that temperature causes when the application conditions change such as to uprise and the clipping distortion that occurs, improve the output tonequality of public address module, promote Consumer's Experience,
Have again, in the present invention, distortion detector and the second time schedule controller are set in clipping control module, in the course of the work, whether the second output signal first utilizing distortion detector to detect in real time to export in public address module there is clipping distortion, once occurred that clipping distortion second time schedule controller reduces the yield value of secondary signal gain immediately start-up time according to the slicing preset, thus eliminate this clipping distortion.After clipping distortion is eliminated, signals revivification slowly controls in amplitude limit amplitude according to the release time of presetting by the second time schedule controller immediately, simple and convenient, and can reach object of the present invention fast.
Accompanying drawing explanation
Below by clearly understandable mode, accompanying drawings preferred implementation, is further described above-mentioned characteristic, technical characteristic, advantage and implementation thereof.
Fig. 1 is input signal and output signal graph of a relation in existing compression amplitude limiter;
Fig. 2 be existing compression amplitude limiter dynamic range less time input signal with output signal graph of a relation;
Fig. 3 outputs signal with input signal variation diagram and system gain figure in existing compression amplitude limiter;
Fig. 4 is the structural representation compressing the first execution mode of amplitude limiter in the present invention;
Fig. 5 is the structural representation compressing amplitude limiter the second execution mode in the present invention;
Fig. 6 is the structural representation compressing the third execution mode of amplitude limiter in the present invention;
Fig. 7 is the graph of a relation between the first signal gain in the present invention, secondary signal gain and system signal gain;
Fig. 8 is the structural representation compressing amplitude limiter the 4th kind of execution mode in the present invention;
Fig. 9 is the graph of a relation in the present invention between the first output signal and reference voltage.
Drawing reference numeral illustrates:
A-start-up time, B-release time, C-slicing start-up time, D-slicing release time, Vref-reference voltage, the amplitude that Vo1-first outputs signal;
100-compresses amplitude limiter, 110-gain regulation module, 120-public address module, 130-clipping control module, 140-Gain selector, 131-distortion detector, 132-second time schedule controller, 111-variable gain amplifier, 112-compression control amplifier, 113-comparator, 114-first time schedule controller.
Embodiment
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, contrast accompanying drawing is illustrated the specific embodiment of the present invention below.Apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings, and obtain other execution mode.
Be illustrated in figure 4 the first execution mode structural representation of compression amplitude limiter 100 provided by the invention, as can be seen from the figure, comprise at this compression amplitude limiter 100: gain regulation module 110, public address module 120 and clipping control module 130, wherein, public address module 120 is connected with gain regulation module 110, and clipping control module 130 is connected with gain regulation module 110 and public address module 120 respectively.In the course of the work, first gain regulation module 110 uses the system signal gain preset to carry out amplification output first to the input signal that system inputs and outputs signal, and judges the amplitude of this first output signal and the relation of compression threshold threshold value V1/ amplitude limit threshold threshold value V2.If the amplitude of the first output signal is beyond compression threshold threshold value V1/ amplitude limit threshold threshold value V2, then gain regulation module 110 can according to this first output signal, feedback regulation is used for the first signal gain (relation of the first signal gain and said system signal gain is: if follow-up second does not occur clipping distortion, then compress this first signal gain is realized input signal by amplitude limiter 100 compression amplitude limit as system signal gain) carrying out compressing amplitude limit to input signal here.Public address module 120 (i.e. public address equipment), after receiving the first output signal, carries out power amplification to it immediately and exports the second output signal, and drives the loud speaker that is connected with public address module 120 to export this second to output signal.
Described above is the workflow compressing amplitude limiter 100 under normal circumstances, if due to a variety of causes (comprise start-up time A long, cause the dynamic range of public address equipment to reduce etc. due to a variety of causes), in the second output signal, output clipping distortion, now clipping control module 130 carries out feedback regulation according to the second output signal exported to secondary signal gain.
Finally, compression amplitude limiter 100 carries out compression amplitude limit according to the first signal gain and secondary signal gain to input signal, and the amplitude of the second output signal exported by compression amplitude limiter 100 controls to export in amplitude limit amplitude, elimination clipping distortion.Certainly, if not there is clipping distortion in the second output signal, then clipping control module 130 can not action, namely feedback regulation can not be carried out to secondary signal gain, and the yield value of secondary signal gain keeps default amplitude limit yield value always, now, amplitude limiter 100 is compressed using the first signal gain as system signal gain.
Be noted that in this embodiment, because the effect of the first signal gain and secondary signal gain is all for regulating and controlling input signal; (exceed amplitude limit amplitude) when the amplitude of input signal is excessive, in the first signal gain and secondary signal gain, select suitable yield value to control in amplitude limit amplitude by the second output signal; When outputing signal amplitude and being too small (being less than amplitude limit amplitude), same suitable yield value of selecting from the first signal gain and secondary signal gain amplifies input signal and exports.Therefore when the feedback regulation of the first signal gain can not solve this clipping distortion, clipping control module 130 realizes this purpose by carrying out feedback regulation to secondary signal gain.Thus, in the process occurring eliminating to clipping distortion from clipping distortion, clipping control module 130 will inevitably reduce the yield value of secondary signal gain rapidly, and the fall off rate of secondary signal gain is greater than the fall off rate of the first signal gain, and in this course compress amplitude limiter 100 using adjustment after secondary signal gain in yield value as system gain value, just can reach the object of elimination clipping distortion.
Above-mentioned execution mode is improved, obtain the second execution mode, as shown in Figure 5, on the basis of the first execution mode, a Gain selector 140 is also comprised in the compression amplitude limiter 100 that present embodiment provides, Gain selector 140 is connected with gain regulation module 110 and clipping control module 130 respectively, and Gain selector 140 is according to the first signal gain and the gain of secondary signal Gain generating system signal, and compression amplitude limiter 100 realizes the compression amplitude limit of input signal according to system signal gain.In a specific embodiment, at synchronization, Gain selector 140 selects less yield value as the yield value in system signal gain in the first signal gain and secondary signal gain, and compression amplitude limiter 100 realizes the compression amplitude limit of input signal according to system signal gain.
According to the description in the first execution mode, we know, in the process occurring eliminating to clipping distortion from clipping distortion, compress amplitude limiter 100 by the yield value in the gain of selection secondary signal as system gain value, therefore in the process of elimination clipping distortion, the yield value of secondary signal gain is obviously less than the yield value of the first signal gain, in other words, although this, yield value of signal gain also can reduce period first, the amplitude reduced does not have the reduction amplitude of secondary signal gain large.In order to avoid the second output signal finally exported is too small, after clipping distortion is eliminated, the yield value that clipping control module 130 can control in secondary signal gain increases gradually, and after this secondary signal gain reaches default amplitude limit yield value, no longer increases.In addition, when there is not clipping distortion in the second output signal, the yield value of secondary signal gain can remain on amplitude limit yield value (now, clipping control module 130 can not adjust secondary signal gain) always; In this process, if the amplitude of the second output signal is too small, compression amplitude limiter 100 can be adjusted by the first signal gain, until its amplitude reaches amplitude limit amplitude, the yield value in the first signal gain in Gain selector 140, is selected to carry out amplifieroperation (yield value of the first signal gain increases gradually but is less than above-mentioned amplitude limit yield value) to input signal in this case.
The second execution mode is improved, obtain the third execution mode, as shown in Figure 6, in the present embodiment, clipping control module 130 comprises distortion detector 131 and the second time schedule controller 132, wherein, distortion detector 131 is connected with public address module 120, and the second time schedule controller 132 is connected with distortion detector 131 and Gain selector 140 respectively.In compression amplitude limiter 100 course of work, the second output signal that distortion detector 131 can continue public address module 120 exports is monitored, and sees and whether occurs clipping distortion.If distortion detector 131 detects that clipping distortion appears in the second output signal, then send clipping distortion signal to the second time schedule controller 132; Second time schedule controller 132 receives this clipping distortion signal, immediately according to the second output signal adjustment secondary signal gain (reducing the yield value of secondary signal gain), and the secondary signal gain after adjustment is sent to Gain selector 140.Subsequently, if distortion detector 131 detects that in the second output signal, clipping distortion eliminates, then send clipping distortion erasure signal to the second time schedule controller 132; After second time schedule controller 132 receives this clipping distortion erasure signal, can adjust the second output gain equally (yield value increasing secondary signal gain), finally the secondary signal gain after adjustment is sent to Gain selector 140.
In a specific embodiment, as shown in Figure 7, the process that adjusts of the second time schedule controller 132 pairs of secondary signal gains is as follows:
When second occurs clipping distortion, according to slicing C start-up time preset, (there is the time that clipping distortion is eliminated in clipping distortion to second time schedule controller 132, amplitude by the second output signal controls the time in slicing amplitude), reduce the yield value of secondary signal gain.In real work, we wish the elimination that the clipping distortion of appearance can be fast as far as possible, therefore here, slicing C start-up time preset usually can be shorter, only has several milliseconds or even delicate level.When the second time schedule controller 132 receives clipping distortion signal, slicing C start-up time that can preset according to this, controlled in slicing amplitude rapidly, and the yield value of secondary signal gain reduces the yield value reduction speed that speed is greater than the first signal gain, during this period, Gain selector 140 selects the yield value of secondary signal gain as the yield value of system signal gain.Yield value as secondary signal gain reduces that speed outputs signal with second, slicing C start-up time and slicing amplitude relevant, can change in real time, at this not to concrete values.In addition, as can be seen from figure we, slicing C start-up time will much smaller than A start-up time (first output signal exceed amplitude limit amplitude to the time controlled in amplitude limit amplitude, start-up time, A was generally several milliseconds to a few tens of milliseconds).
When the second output signal clipping distortion is eliminated, the second time schedule controller 132 increases the yield value of secondary signal gain until amplitude limit yield value according to slicing D release time preset (time by the amplitude that second outputs signal controls in amplitude limit amplitude from slicing amplitude).As can be seen from the figure, in start-up time A, the yield value of the first signal gain is in the state of reduction always, and the yield value of secondary signal gain first can reduce (slicing C start-up time in) and increases (in slicing D release time) again, and in slicing D release time, the yield value that there will be a bit of time secondary signal gain is less than the signal gain value of the first signal (Gain selector 140 selects the yield value of secondary signal gain as system signal gain), the yield value of secondary signal gain afterwards increases to the yield value that is greater than the first signal gain and is in the state (Gain selector 140 selects the yield value of the first signal gain as system signal gain) being greater than the first signal gain always, as shown in Figure 7, until there is the situation of clipping distortion next time, clipping control module 130 adjusts secondary signal gain again, circulate with this.
Above execution mode is improved, obtain present embodiment, as shown in Figure 8, in the present embodiment, gain regulation module 110 comprises a variable gain amplifier 111, compression control amplifier 112, comparator 113 and the first time schedule controller 114, wherein, variable gain amplifier 111 is connected with Gain selector 140, compression control amplifier 112 is connected with variable gain amplifier 111, comparator 113 is connected with variable gain amplifier 111 and compression control amplifier 112 respectively, first time schedule controller 114 is connected with Gain selector 140 and comparator 113 respectively.In the course of the work, the system signal gain that first variable gain amplifier 111 exports according to Gain selector 140 is amplified input signal, exports the first output signal; Compression control amplifier 112 adjusts reference voltage Vref after receiving this first output signal immediately; Then, the first amplitude outputed signal and reference voltage Vref are compared; Finally, the first time schedule controller 114 adjusts the first signal gain according to the comparative result of comparator 113, and by the first signal gain input gain selector 140 after adjustment.
Specifically, as shown in Figure 9, in compression control amplifier 112: when the amplitude of the first output signal is less than compression threshold threshold value V1, compression control amplifier 112 is drawn high with reference to voltage Vref, now reference voltage Vref is inoperative, compress amplitude limiter in this process amplify input signal and export, namely output signal (comprising the first output signal and the second output signal) linear with input signal; When the amplitude of the first output signal is between compression threshold threshold value V1 and amplitude limit threshold threshold value V2, compression controller, according to the compression ratio generating reference voltage Vref preset, compresses voice signal; When the amplitude of the first output signal is greater than amplitude limit threshold threshold value V2, compression controller, with reference to the voltage Vref constant control magnitude of voltage corresponding when compressing amplitude limiter 100 output violent change (amplitude of the second output signal is in amplitude limit amplitude), carries out amplitude limit to input signal.
Compression control amplifier 112 is after adjusting reference voltage Vref, and comparator 113 compares with the amplitude and reference voltage Vref being about to the first output signal.Specifically, when the amplitude of the first output signal is greater than the reference voltage Vref of compression control amplifier 112 output, sends and enter A instruction to the first start-up time time schedule controller 114; When the amplitude of the first output signal is less than the reference voltage Vref of compression control amplifier 112 output, sends and enter B instruction to the first release time time schedule controller 114.
Subsequently, in the first time schedule controller 114: when the first time schedule controller 114 receive enter A instruction start-up time time, first time schedule controller 114, according to A start-up time preset, reduces the yield value of the first signal gain, to control in amplitude limit amplitude by the second output signal; When the first time schedule controller 114 receive enter B instruction release time time, first time schedule controller 114 is according to B release time (generally at hundreds of millisecond by several seconds) preset, increase the yield value of the first signal gain, the first signal gain with input signal change as shown in Figure 7.
Based on above description, in the present invention, detect in public address module (public address equipment) whether occur slicing by distortion detector, if there is, then at once reduce secondary signal gain start-up time by the second time schedule controller according to the slicing preset, and using the secondary signal gain after reduction as system signal gain now, reach the object of elimination clipping distortion.After clipping distortion is removed, increase secondary signal gain immediately, the second output signal is finally controlled to export in amplitude limit amplitude.Thus automatically eliminate in the second output signal due to the clipping distortion that start-up time is long or occur due to the public address module reduced dynamic range caused during the application conditions changes such as output loading change weight, supply voltage step-down, temperature uprise, improve the output tonequality of public address module, improve Consumer's Experience.
It should be noted that above-described embodiment all can independent assortment as required.The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1. compress an amplitude limiter, it is characterized in that, described compression amplitude limiter comprises: gain regulation module, public address module and clipping control module, wherein,
Described gain regulation module, exports the first output signal according to the input signal of described compression amplitude limiter; And according to described first output signal, feedback regulation is for realizing the first signal gain of described input signal compression amplitude limit;
Described public address module, is connected with described gain regulation module, and described public address module carries out power amplification to the first output signal that described gain regulation module exports, and exports the second output signal;
Described clipping control module, be connected with described gain regulation module and described public address module respectively, described clipping control module according to described public address module export second output signal in occur clipping distortion, feedback regulation for realize described input signal compression amplitude limit secondary signal gain;
Described compression amplitude limiter carries out compression amplitude limit according to described first signal gain and described secondary signal gain to described input signal, and the second output signal exported by described compression amplitude limiter controls to export in amplitude limit amplitude.
2. compress amplitude limiter as claimed in claim 1, it is characterized in that: in described compression amplitude limiter, also comprise a Gain selector, described Gain selector respectively with described gain regulation module and described clipping control model calling, described Gain selector is according to described first signal gain and the gain of described secondary signal Gain generating system signal, and described compression amplitude limiter realizes the compression amplitude limit of described input signal according to described system signal gain.
3. compress amplitude limiter as claimed in claim 2, it is characterized in that: at synchronization, described Gain selector selects less yield value as the yield value in system signal gain in described first signal gain and described secondary signal gain, and described compression amplitude limiter realizes the compression amplitude limit of described input signal according to described system signal gain.
4. compress amplitude limiter as claimed in claim 2 or claim 3, it is characterized in that: described clipping control module comprises distortion detector and the second time schedule controller, wherein,
Described distortion detector, is connected with described public address module, described distortion detector for detect described public address module export second output signal in whether there is clipping distortion;
Described second time schedule controller, be connected with described distortion detector and described Gain selector respectively, when described distortion detector detects that described second occurs clipping distortion, secondary signal gain after adjustment according to described second output signal adjustment secondary signal gain, and is sent to described Gain selector by described second time schedule controller.
5. compress amplitude limiter as claimed in claim 4, it is characterized in that,
In described second time schedule controller:
When described second occurs clipping distortion, described second time schedule controller, according to the slicing start-up time of presetting, reduces the yield value of described secondary signal gain;
When described second output signal clipping distortion is eliminated, described second time schedule controller, according to the slicing release time of presetting, increases the yield value of described secondary signal gain.
6. compress amplitude limiter as claimed in claim 5, it is characterized in that: when described second occurs clipping distortion, described second time schedule controller, according to the slicing start-up time of presetting, reduces the yield value of described secondary signal gain; And within described slicing start-up time, the yield value of described secondary signal gain reduces the yield value that speed is greater than described first signal gain and reduces speed.
7. the compression amplitude limiter as described in Claims 2 or 3 or 5 or 6, is characterized in that: described gain regulation module comprises a variable gain amplifier, compression control amplifier, comparator and the first time schedule controller, wherein,
Described variable gain amplifier, is connected with described Gain selector, amplifies input signal according to the system signal gain that described Gain selector exports, and exports the first output signal;
Described compression control amplifier, is connected with described variable gain amplifier, according to described first output signal adjustment reference voltage;
Described comparator, is connected with described variable gain amplifier and described compression control amplifier respectively, and the amplitude of described first output signal and described reference voltage compare by described comparator;
Described first time schedule controller, be connected with described Gain selector and described comparator respectively, described first time schedule controller adjusts the first signal gain according to the comparative result of described comparator, and the first signal gain after adjustment is sent to described Gain selector.
8. compress amplitude limiter as claimed in claim 7, it is characterized in that,
In described compression control amplifier:
When the amplitude of described first output signal is less than compression threshold threshold value, described reference voltage is drawn high by described compression control amplifier;
When the amplitude of described first output signal is between compression threshold threshold value and amplitude limit threshold threshold value, described compression controller is according to the compression ratio generating reference voltage preset;
When the amplitude of described first output signal is greater than amplitude limit threshold threshold value, described compression controller is by magnitude of voltage corresponding to described compression amplitude limiter output violent change for described reference voltage constant control.
9. compress amplitude limiter as claimed in claim 8, it is characterized in that, in described comparator:
When the amplitude of described first output signal is greater than the reference voltage of compression control amplifier output, sends and enter instruction start-up time to described first time schedule controller;
When the amplitude of described first output signal is less than the reference voltage of compression control amplifier output, sends and enter instruction release time to described first time schedule controller.
10. compress amplitude limiter as claimed in claim 9, it is characterized in that, in described first time schedule controller:
When entering instruction start-up time described in described first time schedule controller receives, described first time schedule controller, according to the start-up time of presetting, reduces the yield value of described first signal gain;
When entering instruction release time described in described first time schedule controller receives, described first time schedule controller, according to the release time of presetting, increases the yield value of described first signal gain;
Described start-up time much larger than described slicing start-up time.
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| US20100321109A1 (en) * | 2009-02-05 | 2010-12-23 | Quantance, Inc. | Amplifier Compression Adjustment Circuit |
| CN102740212A (en) * | 2011-04-13 | 2012-10-17 | 奥迪康有限公司 | Hearing device with automatic clipping prevention and corresponding method |
| CN103326677A (en) * | 2012-03-22 | 2013-09-25 | 炬力集成电路设计有限公司 | Audio power amplifier and adjusting method thereof |
| CN205212792U (en) * | 2015-11-30 | 2016-05-04 | 上海若瓦鑫电子技术有限公司 | Compression clipper -limiter |
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2015
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100321109A1 (en) * | 2009-02-05 | 2010-12-23 | Quantance, Inc. | Amplifier Compression Adjustment Circuit |
| CN102740212A (en) * | 2011-04-13 | 2012-10-17 | 奥迪康有限公司 | Hearing device with automatic clipping prevention and corresponding method |
| CN103326677A (en) * | 2012-03-22 | 2013-09-25 | 炬力集成电路设计有限公司 | Audio power amplifier and adjusting method thereof |
| CN205212792U (en) * | 2015-11-30 | 2016-05-04 | 上海若瓦鑫电子技术有限公司 | Compression clipper -limiter |
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