CN205793249U - The circuit of automatic mute during the input of a kind of no signal - Google Patents
The circuit of automatic mute during the input of a kind of no signal Download PDFInfo
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- CN205793249U CN205793249U CN201620481821.6U CN201620481821U CN205793249U CN 205793249 U CN205793249 U CN 205793249U CN 201620481821 U CN201620481821 U CN 201620481821U CN 205793249 U CN205793249 U CN 205793249U
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Abstract
The circuit of automatic mute when the utility model discloses the input of a kind of no signal.This utility model relates to electronic technology field, quiet more practical for realizing, more cylinder list and design, being mainly used in the active case of multimedia teaching, the equipment such as power amplification, owing to most of equipment lines are long, multi-thread tie together etc. all can produce the biggest interfering noise, apply this circuit can be effectively prevented these noises do not teaching, examination, review one's lessons and wait the unnecessary noise of period appearance.
Description
Technical field
This utility model relates to the circuit of automatic mute during the input of a kind of no signal.
Background technology
nullThere are plurality of devices in universities, middle and primary schools unavoidably when installing multimedia equipment,There is equipment the most leaded,If tone frequency channel wire、Power line、Video line ties together unavoidable generation and disturbs signal，Active case，Typically all it is placed on the both sides wall in classroom，At least the line that several rice is long is had from dais，Because computer and microphone are all placed on dais，The audio signal of these computers and microphone signal source are bundled in same wire casing simultaneously through several meters of long lines and with the power line of power supply the most again，The tone frequency channel wire tied together often produces interference (also having even if doing tone frequency channel wire with shielding line)，And once these signals are input to power-amplifier stage,After power-amplifier stage amplifies,The noise that people's least original meaning is listened will be heard at audio amplifier,Just these noise parts can be removed if we quote quietness technology with little money,Thus can go back the quiet environment in one, classroom.
Summary of the invention
For solving above-mentioned technical problem, the circuit of automatic mute when this utility model provides the input of a kind of no signal, including by amplified signal level, rectifying and wave-filtering, auto-changing circuit, quiet control.
The beneficial effects of the utility model: computer audio frequency, MP3, disc player, the signal source such as microphone input, it connects machine preamplifier state and amplified signal level, preamplifier state output connects quiet control, quiet control is connected to the input of power-amplifier stage, and amplified signal level is connected to rectifying and wave-filtering, and rectifying and wave-filtering connects automatic output transform circuit, being allowed to export malleation or negative pressure according to the condition that the output of automatic output transform circuit has set, automatic output transform circuit is connected to quiet control.According to the audion of the quiet control of Control of Voltage of automatic output transform circuit output, thus control the input of power-amplifier stage below or low level or high level, make power-amplifier stage realize during no audio signal quiet.
When there being source of sound to input, power-amplifier stage normally works, and when inputting without source of sound, rectifying and wave-filtering, auto-changing circuit, quiet control can filter off unnecessary interference signal, and power-amplifier stage does not works.
Accompanying drawing explanation
Automatic mute principle assumption diagram during the input of Fig. 1 this utility model no audio signal.
Detailed description of the invention
With detailed description of the invention, this utility model is further elaborated below in conjunction with the accompanying drawings
As it is shown in figure 1, the operation principle of the circuit of automatic mute is as follows during no signal input:
null1,Described without audio frequency letter input time，First when no signal (including without noise)，Through R1,R2 resistance does not has current/voltage to pass through，The 3 foot no-voltages of U1A，Amplified signal level output no signal，After R9 resistance, several exhaling of voltage is zero，It is negligible，Now D10 diode is without commutating voltage，Resistance also no-voltage through R9 flows through，Therefore the 5 foot voltages of U1B are zero，Now the 6 foot voltages of U1B are more than 5 foot voltages，Owing to U1B is open loop computing circuit，When the 5 foot voltages of U1B are more than 6 foot，Owing to 5 feet are the positive input terminal of IC，7 feet are output as malleation，On the contrary when the 5 foot voltages of U1B are less than 6 foot voltage，Owing to 6 feet are IC negative terminal input，When 6 foot inputs are more than the positive voltage of 5 feet,7 feet of U1B are output as anti-phase output，Output voltage is the negative voltage that U1B powers，Owing to 5 feet now do not have voltage，So the voltage of 7 foot outputs is negative voltage，Base stage through current-limiting resistance R13 to audion GB1，GB1 is PNP pipe，Its base stage is when for negative voltage，Now audion road leads to，In the past big signal is put through audion GB1 because colelctor electrode is to connect ground，So the signal of process has also just descended ground，Power-amplifier stage input is low level，Power-amplifier stage is without output.Audio amplifier is the quietest
2, described no audio signal, but there is noise to be input to input, now noise one tunnel is amplified through prestage amplifier stage, another road is through amplified signal level, signal after amplified signal level amplification is through diode D10 rectification, through C6 capacitor filtering, one voltage of energy storage, this flows to 5 feet of U1B through R9 resistance, the voltage that comes from R11 resistance is through R12 dividing potential drop, we can change the parameter of resistance R11 and R12, it is allowed to the size of the voltage of U1B6 foot, we can set R11 according to the size of on-site signal noise, the parameter of R22, make the voltage of U1B6 foot more than 5 foot voltages, 7 foot output or the negative voltages of U1B.Through current-limiting resistance R13G to GB1 transistor base, GB1 is PNP pipe, its base stage is when for negative voltage, now audion road leads to, and the signal amplified from preamplifier state is sent out through audion GB1 and to be thanked to electrode, because colelctor electrode is to connect ground, owing to this audion road leads to, so the noise signals through preamplifier state amplification has also just descended ground, power-amplifier stage input is low level, and power-amplifier stage is without output.Audio amplifier is the quietest
null3，Described when having audio signal or microphone signal to be input to input，Signal one tunnel now is amplified through preamplifier state，Another road is amplified through amplified signal level，Signal after amplified signal level amplification is through diode D10 rectification，Through C6 capacitor filtering，5 feet through resistance R9 to U1B，Owing to signal amplitude now is bigger，R11，The parameter that R12 is arranged makes the voltage voltage much smaller than 5 feet of 6 feet，Again due to input U1B 5 foot voltages be positive voltage，So the 7 foot outputs of U1B are malleation output，So now 7 feet of U1B export one close to U1A positive supply voltage，This voltage arrives GB1 base stage after resistance R3 current limliting，Owing to GB1 is PNP pipe，GB1 ends，Audio signal signal after preamplifier state is amplified is input to the input of power-amplifier stage smoothly，Power-amplifier stage normally works.
null4，People speak or computer signal out all can have pause，But the audio signal that power-amplifier stage is released can not feel there is docking phenomenon，C6 electric capacity the most just works，When audio signal or people speak the little stopping time，The voltage due to C6 energy storage，Now C6 electric discharge，Electric current continues the voltage to U1B5 foot through resistance R9 and will not suddenly change，5 feet of U1B maintain positive voltage during signal input，The 7 foot outputs of U1B or positive voltage export，So now 7 feet of U1B still export one close to U1A supply voltage，This voltage arrives GB1 base stage after resistance R3 current limliting，Owing to GB1 is PNP pipe，GB1 ends，Audio signal signal after preamplifier state is amplified is input to the input of power-amplifier stage smoothly，Power-amplifier stage is also in normal work，So not havinging staccato phenomenon yet.
Claims (1)
1. the circuit of automatic mute during a no signal input, it is characterized in that: the input of described signal connects preamplifier state and amplified signal level, preamplifier state output connects quiet control, quiet control is connected to the input of power-amplifier stage, amplified signal level is connected to rectifying and wave-filtering, rectifying and wave-filtering connects automatic output transform circuit, is allowed to export malleation or negative pressure according to the condition that the output of automatic output transform circuit has set, and automatic output transform circuit is connected to quiet control；The audion (road lead to) of the quiet control of Control of Voltage according to the output of automatic output transform circuit or (cut-off), thus the input of the power-amplifier stage that control is below or low level or high level, power-amplifier stage is made to realize during no audio signal quiet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620481821.6U CN205793249U (en) | 2016-05-25 | 2016-05-25 | The circuit of automatic mute during the input of a kind of no signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620481821.6U CN205793249U (en) | 2016-05-25 | 2016-05-25 | The circuit of automatic mute during the input of a kind of no signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205793249U true CN205793249U (en) | 2016-12-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620481821.6U Active CN205793249U (en) | 2016-05-25 | 2016-05-25 | The circuit of automatic mute during the input of a kind of no signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205793249U (en) |
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2016
- 2016-05-25 CN CN201620481821.6U patent/CN205793249U/en active Active
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