CN201937547U - Static noise elimination circuit for audio-frequency amplifier - Google Patents
Static noise elimination circuit for audio-frequency amplifier Download PDFInfo
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- CN201937547U CN201937547U CN201120034298XU CN201120034298U CN201937547U CN 201937547 U CN201937547 U CN 201937547U CN 201120034298X U CN201120034298X U CN 201120034298XU CN 201120034298 U CN201120034298 U CN 201120034298U CN 201937547 U CN201937547 U CN 201937547U
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Abstract
The utility model provides a static noise elimination circuit for an audio-frequency amplifier, which comprises a negative terminal feedback signal circuit, a positive terminal feedback signal circuit, a negative feedback signal off-center circuit, a gain control circuit and a delay filter circuit, wherein the input end of the negative terminal feedback signal circuit is connected with the negative output end of the audio-frequency amplifier; the input end of the positive terminal feedback signal circuit is connected with the positive output end of the audio-frequency amplifier; the input end of the negative feedback signal off-center circuit is connected with the output ends of both the negative and the positive terminal feedback signal circuits; the input end of the gain control circuit is connected with the output end of the negative feedback signal off-center circuit; and the input end of the delay filter circuit is connected with the output end of the gain control circuit, and the output end of the delay filter circuit is connected with the audio-frequency amplifier. By adopting the static noise elimination circuit provided by the utility model, no noise occurs in a loudspeaker when no audio-frequency input signals exist.
Description
Technical field
The utility model relates to electronic system, and particularly audio frequency amplifier relates in particular to the noise control circuit of audio frequency amplifier.
Background technology
Audio signal in the source of sound and noise enter into the input of audio frequency amplifier by the audio frequency incoming line, through outputing to loudspeaker after the audio frequency amplifier processing, when the audio signal input is arranged, the amplitude of audio signal is much larger than the amplitude of noise signal, embody not obviously in loudspeaker, when not having the audio signal input, noise signal outputs to loudspeaker after amplifying, loudspeaker send apparent in view noise, and people's ear is easy to distinguish.
Summary of the invention
In order to improve The noise, the purpose of this utility model is to provide a kind of audio frequency amplifier noise control circuit.
The technical solution adopted in the utility model is:
The static noise of at first a kind of audio frequency amplifier of the utility model is eliminated circuit, comprises: the negative terminal feedback signal circuit, and its input is connected with the negative output terminal of audio frequency amplifier; The anode feedback signal circuit, its input is connected with the positive output end of audio frequency amplifier; The negative-feedback signal off-centre circuit, its input is connected with the output of negative terminal feedback signal circuit with the anode feedback signal circuit; Gain control circuit, its input is connected with the output of negative-feedback signal off-centre circuit; And the delay filtering circuit, its input is connected with the output of gain control circuit, and its output is connected with audio frequency amplifier.
In the utility model one embodiment, described negative-feedback signal off-centre circuit receives from the positive feedback signal of the negative-feedback signal of described negative terminal feedback signal circuit and described anode feedback signal circuit, calculates the offset deviation between positive feedback signal and the negative-feedback signal, and this offset deviation is passed to described gain control circuit.
In the utility model one embodiment, described gain control circuit judges it is noise or signal plus noise according to the offset deviation that receives, when noise threshold that noise surpass to be set, control circuit send reduce the audio frequency amplifier gain order to the delay filtering circuit.
In the utility model one embodiment, described delay filtering circuit is by delay filtering control audio Amplifier Gain.
The utility model provides a kind of audio system in addition, and its static noise that comprises above-mentioned any audio frequency amplifier is eliminated circuit.
The static noise of another audio frequency amplifier of the utility model is eliminated circuit, comprises: feedback signal circuit, and its input is connected with the positive output end of audio frequency amplifier and a wherein end of negative output terminal; The negative-feedback signal off-centre circuit, its input is connected with the output of feedback signal circuit; Gain control circuit, its input is connected with the output of negative-feedback signal off-centre circuit; And the delay filtering circuit, its input is connected with the output of gain control circuit, and its output is connected with audio frequency amplifier.
In the utility model one embodiment, described negative-feedback signal off-centre circuit receives feedback signal from described feedback signal circuit, calculates this feedback signal with the offset deviation between the common-mode signal in the circuit, and this offset deviation is passed to described gain control circuit.
In the utility model one embodiment, described gain control circuit judges it is noise or signal plus noise according to the offset deviation that receives, when noise threshold that noise surpass to be set, gain control circuit send reduce the audio frequency amplifier gain order to the delay filtering circuit.
In the utility model one embodiment, described delay filtering circuit is by delay filtering control audio Amplifier Gain.
The utility model provides a kind of audio system again, and its static noise that comprises above-mentioned each described audio frequency amplifier is eliminated circuit.
Because the utility model adds feedback circuit at positive-negative output end, positive feedback signal transfers back to the prime control circuit with the offset deviation between the negative-feedback signal, it is noise or signal plus noise that control circuit is judged, when noise surpasses the noise threshold of setting, control circuit sends the order that reduces the audio frequency amplifier gain, by control audio Amplifier Gain after certain delay filtering, therefore when not having audio input signal, loudspeaker do not have noise.
The utility model adds feedback circuit at the positive output end or the negative output terminal of audio frequency amplifier, feedback signal with common-mode signal in the circuit relatively, the deviation that draws feedback signal transfers back to the prime control circuit, it is noise or signal plus noise that control circuit is judged, when noise surpasses the noise threshold of setting, control circuit sends the order that reduces the audio frequency amplifier gain, by control audio Amplifier Gain after certain delay filtering, therefore when not having audio input signal, loudspeaker do not have noise.
Below in conjunction with accompanying drawing enforcement of the present utility model and advantage are further explained.
Description of drawings
Fig. 1 is a block diagram of eliminating circuit according to the static noise of a kind of audio frequency amplifier of the present utility model;
Fig. 2 is a block diagram of eliminating circuit according to the static noise of another kind of audio frequency amplifier of the present utility model;
Fig. 3 is a block diagram of eliminating circuit according to the static noise of another audio frequency amplifier of the present utility model;
Fig. 4 is the contrast waveform schematic diagram of the input of the utility model noise, output.
Embodiment
The explanation of relevant embodiment of the present utility model is graphic with reference to what add, can be in order to the specific embodiment of implementing in order to illustration the utility model.In following examples, in different figure, same section is to represent with same numeral.Fig. 1 shows first preferred embodiment of the present utility model, and Fig. 2 to Fig. 3 shows second embodiment of the present utility model, and Fig. 4 has illustrated the contrast waveform of noise of the present utility model input, output.
With reference to figure 1.Static noise according to the audio frequency amplifier of the utility model first preferred embodiment is eliminated circuit 10, comprises: negative terminal feedback signal circuit 13, and its input is connected with the negative output terminal of audio frequency amplifier 12; Anode feedback signal circuit 14, its input is connected with the positive output end of audio frequency amplifier 12; Negative-feedback signal off-centre circuit 15, its input is connected with the output of negative terminal feedback signal circuit 13 with anode feedback signal circuit 14; Gain control circuit 16, its input is connected with the output of negative-feedback signal off-centre circuit 15; And delay filtering circuit 17, its input is connected with the output of gain control circuit 16, and its output is connected with audio frequency amplifier 12.Audio frequency amplifier 12 can output signal to loudspeaker 11.
Continuation is with reference to figure 1.In the utility model one embodiment, described negative-feedback signal off-centre circuit 15 receives from the positive feedback signal of the negative-feedback signal of described negative terminal feedback signal circuit 13 and described anode feedback signal circuit 14, calculates the offset deviation between positive feedback signal and the negative-feedback signal, and this offset deviation is passed to described gain control circuit 16.Described gain control circuit 16 judges it is noise or signal plus noise according to the offset deviation that receives, when noise surpasses the noise threshold of setting, gain control circuit 16 send reduce audio frequency amplifier gain order to delay filtering circuit 17, this mainly comprises two kinds of situations, when input signal only is noise and when the threshold value of noise in the input signal during greater than audio signal.In the utility model one embodiment, described delay filtering circuit 17 is by the gain of delay filtering control audio amplifier 12.
The utility model provides a kind of audio system in addition, and its static noise that comprises above-mentioned any audio frequency amplifier is eliminated circuit.Simultaneously, the static noise of the utility model audio frequency amplifier is eliminated circuit also can add feedback circuit at the positive output end or the negative output terminal of audio frequency amplifier, feedback signal with common-mode signal in the circuit relatively, the deviation that draws feedback signal transfers back to the prime control circuit, it is noise or signal plus noise that control circuit is judged, when noise surpasses the noise threshold of setting, control circuit sends the order that reduces the audio frequency amplifier gain, by control audio Amplifier Gain after certain delay filtering.
With reference to figure 2.The static noise of a kind of audio frequency amplifier of foundation second embodiment of the present utility model is eliminated circuit 20 and is comprised: feedback signal circuit 23, and its input is connected with the positive output end of audio frequency amplifier 22; Negative-feedback signal off-centre circuit 24, its input is connected with the output of feedback signal circuit 23; Gain control circuit 25, its input is connected with the output of negative-feedback signal off-centre circuit 24; And delay filtering circuit 26, its input is connected with the output of gain control circuit 25, and its output amplifies 22 devices with audio frequency and is connected.Audio frequency amplifier 22 can output signal to loudspeaker.
Continuation is with reference to figure 2.In the utility model one embodiment, described negative-feedback signal off-centre circuit 24 receives feedback signal from described feedback signal circuit 23, calculates this feedback signal with the offset deviation between the common-mode signal in the circuit, and this offset deviation is passed to described gain control circuit 25.In the utility model one embodiment, described gain control circuit 25 judges it is noise or signal plus noise according to the offset deviation that receives, when noise surpasses the noise threshold of setting, gain control circuit 25 send reduce audio frequency amplifier gain order to delay filtering circuit 26, also be when input signal only is noise and when the threshold value of noise in the input signal, to regulate during greater than audio signal.In the utility model one embodiment, described delay filtering circuit 26 is by the gain of delay filtering control audio amplifier 22.
Fig. 3 shows according to the static noise of the another kind of audio frequency amplifier of the utility model second embodiment and eliminates circuit 30, with static noise shown in Figure 2 eliminate circuit 20 different be that feedback circuit is added to the negative output terminal of audio frequency amplifier.As shown in the figure, the input of feedback signal circuit 27 is connected with the negative output terminal of audio frequency amplifier; The input of negative-feedback signal off-centre circuit 28 is connected with the output of feedback signal circuit 27; The input of gain control circuit 25 is connected with the output of negative-feedback signal off-centre circuit 28; And the input of delay filtering circuit 26 is connected with the output of gain control circuit 25, and the output of delay filtering circuit 26 is connected with audio frequency amplifier 22.
The utility model provides a kind of audio system again, and it comprises by the static noise of Fig. 2, above-mentioned each described audio frequency amplifier illustrated in Figure 3 eliminates circuit.Comprising the audio system of eliminating circuit to the static noise of audio frequency amplifier shown in Figure 3 by Fig. 1 can be digital audio amplifier, active noise removing earphone etc., further, these audio systems can be used for any electronic equipment or electric equipment that can adopt it.
Audio frequency amplifier noise control circuit of the present utility model makes source of sound be input to audio frequency amplifier through tone frequency channel wire, audio frequency amplifier outputs to loudspeaker through amplifying signal, output is with feedback control circuit is arranged between the gain controlling, information according to audio frequency amplifier output, the size of ride gain is suppressed at the output when not having audio signal.Fig. 4 has shown the improve effect of employing the technical solution of the utility model to noise, as shown in the figure, the noise signal of prior art outputs to loudspeaker after amplifying, loudspeaker send apparent in view noise, and the application's technical scheme is not then amplified simple noise.
When not importing having only noise, turns off the utility model output, a bit picture static noise technology for eliminating.
Certainly, more than only be concrete exemplary applications of the present utility model, protection range of the present utility model is not constituted any limitation.In addition to the implementation, the utility model can also have other execution mode.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop within the utility model scope required for protection.
Claims (10)
1. the static noise of an audio frequency amplifier is eliminated circuit, it is characterized in that, comprises:
The negative terminal feedback signal circuit, its input is connected with the negative output terminal of audio frequency amplifier;
The anode feedback signal circuit, its input is connected with the positive output end of audio frequency amplifier;
The negative-feedback signal off-centre circuit, its input is connected with the output of negative terminal feedback signal circuit with the anode feedback signal circuit;
Gain control circuit, its input is connected with the output of negative-feedback signal off-centre circuit; And
The delay filtering circuit, its input is connected with the output of gain control circuit, and its output is connected with audio frequency amplifier.
2. the static noise of audio frequency amplifier according to claim 1 is eliminated circuit, it is characterized in that, described negative-feedback signal off-centre circuit receives from the positive feedback signal of the negative-feedback signal of described negative terminal feedback signal circuit and described anode feedback signal circuit, calculates the offset deviation between positive feedback signal and the negative-feedback signal, and this offset deviation is passed to described gain control circuit.
3. the static noise of audio frequency amplifier according to claim 1 is eliminated circuit, it is characterized in that, described gain control circuit judges it is noise or signal plus noise according to the offset deviation that receives, when noise threshold that noise surpass to be set, gain control circuit send reduce the audio frequency amplifier gain order to the delay filtering circuit.
4. the static noise of audio frequency amplifier according to claim 1 is eliminated circuit, it is characterized in that described delay filtering circuit is by delay filtering control audio Amplifier Gain.
5. an audio system is characterized in that, the static noise that comprises each described audio frequency amplifier among the claim 1-4 is eliminated circuit.
6. the static noise of an audio frequency amplifier is eliminated circuit, it is characterized in that, comprises:
Feedback signal circuit, its input is connected with the positive output end of audio frequency amplifier and a wherein end of negative output terminal;
The negative-feedback signal off-centre circuit, its input is connected with the output of feedback signal circuit;
Gain control circuit, its input is connected with the output of feedback signal off-centre circuit; And
The delay filtering circuit, its input is connected with the output of gain control circuit, and its output is connected with audio frequency amplifier.
7. the static noise of audio frequency amplifier according to claim 6 is eliminated circuit, it is characterized in that, described negative-feedback signal off-centre circuit receives feedback signal from described feedback signal circuit, calculates this feedback signal with the offset deviation between the common-mode signal in the circuit, and this offset deviation is passed to described gain control circuit.
8. the static noise of audio frequency amplifier according to claim 6 is eliminated circuit, it is characterized in that, described gain control circuit judges it is noise or signal plus noise according to the offset deviation that receives, when noise threshold that noise surpass to be set, gain control circuit send reduce the audio frequency amplifier gain order to the delay filtering circuit.
9. the static noise of audio frequency amplifier according to claim 6 is eliminated circuit, it is characterized in that described delay filtering circuit is by delay filtering control audio Amplifier Gain.
10. an audio system is characterized in that, the static noise that comprises each described audio frequency amplifier among the claim 6-9 is eliminated circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120034298XU CN201937547U (en) | 2011-02-01 | 2011-02-01 | Static noise elimination circuit for audio-frequency amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120034298XU CN201937547U (en) | 2011-02-01 | 2011-02-01 | Static noise elimination circuit for audio-frequency amplifier |
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| Publication Number | Publication Date |
|---|---|
| CN201937547U true CN201937547U (en) | 2011-08-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201120034298XU Expired - Lifetime CN201937547U (en) | 2011-02-01 | 2011-02-01 | Static noise elimination circuit for audio-frequency amplifier |
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| CN (1) | CN201937547U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102195566A (en) * | 2011-02-01 | 2011-09-21 | 上海矽诺微电子有限公司 | Static noise cancelling circuit of audio amplifier |
-
2011
- 2011-02-01 CN CN201120034298XU patent/CN201937547U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102195566A (en) * | 2011-02-01 | 2011-09-21 | 上海矽诺微电子有限公司 | Static noise cancelling circuit of audio amplifier |
| CN102195566B (en) * | 2011-02-01 | 2013-02-27 | 上海矽诺微电子有限公司 | Static noise cancelling circuit of audio amplifier |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20110817 |