CN202475675U - Network type set top box silencing circuit - Google Patents
Network type set top box silencing circuit Download PDFInfo
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- CN202475675U CN202475675U CN2011205721484U CN201120572148U CN202475675U CN 202475675 U CN202475675 U CN 202475675U CN 2011205721484 U CN2011205721484 U CN 2011205721484U CN 201120572148 U CN201120572148 U CN 201120572148U CN 202475675 U CN202475675 U CN 202475675U
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Abstract
The utility model relates to a network type set top box silencing circuit, comprising an active silencing control circuit, a powering-on impact noise elimination control circuit, a powering-off impact noise elimination control circuit, and a common portion of the silencing circuit, wherein the active silencing control circuit, the powering-on impact noise elimination control circuit, a powering-off impact noise elimination control circuit are respectively connected with the common portion of the silencing circuit, the active silencing control circuit is connected with the powering-off impact noise elimination control circuit, and the powering-off impact noise elimination control circuit is connected with the powering-on impact noise elimination control circuit. The network type set top box silencing circuit not only can perfectly eliminate powering on and off impact noises, but also is reasonable in power supply design and strong in circuit reliability.
Description
[technical field]
The utility model relates to a kind of mute circuit, specifically is meant a kind of network edition STB mute circuit.
[background technology]
In the inserted audio-video circuit, mute function need satisfy the user to quiet needs, when cut bank, standby, switching on and shutting down and software startup, all will play quiet effect.Generally can adopt software control audio decoder process or control audio digital to analog converter DAC to realize mute function; But be not easy to realize aspect the noise of these two kinds of methods when control switch machine and audio digital to analog converter DAC startup, cause quiet effect undesirable.
When existing muting control circuit starts at user's start, shutdown or master chip internal audio frequency digital to analog converter DAC; Power supply by transient state to the stable state transition period; The noise of inside circuit amplifies through amplifying circuit, when exporting power amplifier loud speaker or audio amplifier to, can send " bang " plosive.Noise when said open and close machine and audio digital to analog converter DAC start can directly influence user's auditory effect.
Present switching on and shutting down impact noise elimination circuit is not ideal, and quiet effect lacks perfection, and reaction speed is slow, poor anti jamming capability.And function is single relatively, has some complicated relatively again with the circuit of manual mute function, some is arranged even adopted operational amplification circuit.Also having some is to cooperate the chip of external belt mute function to realize.Key is that present switching on and shutting down impact noise is eliminated control circuit a very big defective is arranged, and is promptly relatively poor for the noise suppression effect of high-speed switch machine repeatedly.
China's utility model patent 201010249839.0 discloses a kind of switching on and shutting down automatic mute circuit of inserted audio-video equipment; As shown in Figure 1; This circuit comprises three parts, and the start impact noise is eliminated control circuit, the shutdown impact noise is eliminated control circuit and active muting control circuit.The start impact noise is eliminated control circuit and is made up of triode Q6, resistance R 9, capacitor C D2, diode D3; Shutdown impact noise elimination control circuit is made up of triode Q5, diode D2, capacitor C D1, resistance R 7, resistance R 8, and initiatively muting control circuit comprises triode Q1, triode Q2, resistance R 1, resistance R 2, resistance R 3, resistance R 4.The switching on and shutting down impact noise of this circuit is eliminated control circuit, and to belong to hardware quiet, and quiet quiet with shutdown moment in system boot moment, this mute circuit is can't provide quiet situation to use at software.It is quiet to belong to hardware but the switching on and shutting down impact noise is eliminated control circuit, can only solve the noise problem of moment, after getting up for system, hopes long quiet of relative time, then need be through the initiatively quiet mode of software.
Also there is following shortcoming in the technical scheme of above-mentioned patent: 1, the start impact noise is eliminated control circuit, the shutdown impact noise is eliminated control circuit and active muting control circuit; The power supply of three part uses is VCC_Audio; Just exist unreasonable on such design theory; Hope using system that group power supply the earliest that powers on because the start impact noise is eliminated control circuit, the shutdown impact noise eliminate being that control circuit hopes to use down the fastest that of electricity organize power supply.2, initiatively the effect of muting control circuit in this circuit all be confined to system get up later quiet, to system's effect that do not have at that time that powers on.3, there is design defect in start impact noise elimination control circuit, and capacitor C D2 can't be full of, and causes turn-on muting unreliable, occurs at VCC_Audio unusual quiet action might occurring under the situation of fluctuation.
[summary of the invention]
The utility model technical problem to be solved is to provide a kind of network edition STB mute circuit, not only can perfectly eliminate the switching on and shutting down impact noise, and power supply is reasonable in design, the good reliability of circuit.
The utility model adopts following technical scheme to solve the problems of the technologies described above:
Network edition STB mute circuit comprises initiatively muting control circuit, and the start impact noise is eliminated control circuit, and the shutdown impact noise is eliminated control circuit, and the public part of mute circuit; Said active muting control circuit, start impact noise are eliminated control circuit, the shutdown impact noise is eliminated control circuit and is connected with the public part of said mute circuit respectively; Said active muting control circuit connects said shutdown impact noise and eliminates control circuit; Said shutdown impact noise is eliminated control circuit and is connected said start impact noise elimination control circuit.
The public part of said mute circuit comprises diode D1, resistance R 5, R6, triode Q3, Q4; Two anodes of said diode D1 connect said active muting control circuit respectively, said start impact noise is eliminated control circuit, said shutdown impact noise elimination control circuit; The negative electrode of said diode D1 divides two-way to connect resistance R 5 and resistance R 6 respectively; Resistance R 5 other ends connect the base stage of triode Q3, the base stage that resistance R 6 other ends connect triode Q4; The collector electrode of triode Q3 is connected to audio signal output end; The collector electrode of triode Q4 also is connected to audio signal output end; The equal ground connection of the emitter of triode Q3, Q4;
Said active muting control circuit comprises resistance R 1, R2, R3, R4, triode Q1, Q2, diode D4, capacitor C D4; The emitter of triode Q1 is connected to system power supply; The collector electrode of triode Q1 is connected to the public part of said mute circuit through resistance R 1; The base stage of triode Q1 divides three the tunnel, the one tunnel to be connected to the collector electrode of triode Q2 through resistance R 3, and another road is connected to system power supply+5V_STB through resistance R 2 with its diode connected in parallel D4, and another road is through capacitor C D4 ground connection; The base stage of triode Q2 is connected to the MUTE end through resistance R 4; The grounded emitter of triode Q2;
Said shutdown impact noise is eliminated control circuit, comprises resistance R 7, R8, triode Q5, capacitor C D1, diode D2; The ground level of triode Q5 is connected to power supply VCC5V through resistance R 8; The collector electrode of triode Q5 is connected respectively to the public part and the said start impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q5 divides two-way, and one the tunnel connects diode D2 negative electrode, and another road is connected to capacitor C D1 anode through resistance R 7; Capacitor C D1 minus earth; Diode D2 anode is connected to power supply VCC5V;
Said start impact noise is eliminated control circuit, comprises triode Q6, diode D3, resistance R 9, resistance R 9, capacitor C D2; Triode Q6 collector electrode is connected to the public part and the said shutdown impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q6 is connected to power supply VCC12V; The base stage of triode Q6 connects resistance R 9; Resistance R 9 other ends divide two-way, the one road be connected to diode D3 anode and with its parallel resistor R10, the one tunnel connects capacitor C D2 anode; Diode D3 negative electrode and receive power supply VCC12V with its parallel resistor R10; Capacitor C D2 minus earth.
The advantage of the utility model is: same group of the power sharing of the impact noise of 1, no longer will starting shooting elimination control circuit, shutdown impact noise elimination control circuit and active muting control circuit; But the start impact noise eliminates control circuit and uses VCC12V, and this group power supply is that power in the set-top-box system the earliest that organized power supply; The shutdown impact noise is eliminated control circuit and is used VCC5V to be that group power supply early of electricity under the system; And the use of active muting control circuit is with the same power supply of SCM system.Such power supply design more reasonable.2, initiatively muting control circuit increases capacitor C D4 and diode D4; The benefit of design is that initiatively muting control circuit also can play effect in the beginning part that system powers on like this; As long as SCM system is come together, just can play quiet effect, general set-top-box system all can use the single-chip microcomputer mini system; Be used for button start, infrared function or the like; SCM system regular software function is fairly simple, and system gets up than comparatively fast, can remedy the start impact noise and eliminate defective of a specified duration inadequately of quiet duration of control circuit.3, the start impact noise is eliminated control circuit increases resistance R 10, and the purpose of design is to eliminate the defective of circuit like this, if do not add resistance R10; Occur under the situation of fluctuation at the VCC12V of system; Quiet when system will have, not quiet sometimes, circuit reliability is relatively poor.Increase resistance R 10, guarantee that the cathode voltage of capacitor C D2 can reach with power supply VCC12V, occur at the VCC12V power supply under the situation of fluctuation, also can not occur unnecessary quietly, the reliability of circuit has strengthened.
[description of drawings]
Combine embodiment that the utility model is done further to describe with reference to the accompanying drawings.
Fig. 1 is the prior art circuits structural representation.
Fig. 2 is the utility model electrical block diagram.
[embodiment]
Network edition STB mute circuit sees also shown in Figure 2ly, comprises initiatively muting control circuit, and the start impact noise is eliminated control circuit, and the shutdown impact noise is eliminated control circuit, and the public part of mute circuit; Said active muting control circuit, start impact noise are eliminated control circuit, the shutdown impact noise is eliminated control circuit and is connected with the public part of said mute circuit respectively; Said active muting control circuit connects said shutdown impact noise and eliminates control circuit; Said shutdown impact noise is eliminated control circuit and is connected said start impact noise elimination control circuit.
The public part of mute circuit comprises diode D1, resistance R 5, R6, triode Q3, Q4; The anode of said diode D1 connects said active muting control circuit respectively, and said start impact noise is eliminated control circuit, and said shutdown impact noise is eliminated control circuit; The negative electrode of said diode D1 divides two-way to connect resistance R 5 and resistance R 6 respectively; Resistance R 5 other ends connect the base stage of triode Q3, the base stage that resistance R 6 other ends connect triode Q4; The collector electrode of triode Q3 is connected to audio signal output end OUT_L; The collector electrode of triode Q4 is connected to audio signal output end OUT_R; The equal ground connection of the emitter of triode Q3, Q4.When triode Q3, Q4 conducting, audio signal OUT _ L and OUT_R are clamped to signal ground, reach quiet effect.
Initiatively muting control circuit comprises resistance R 1, R2, R3, R4, triode Q1, Q2, diode D4, capacitor C D4; The emitter of triode Q1 is connected to system power supply+5V_STB; The collector electrode of triode Q1 is connected to the public part of said mute circuit through resistance R 1; The base stage of triode Q1 divides three the tunnel, the one tunnel to be connected to the collector electrode of triode Q2 through resistance R 3, and another road is connected to system power supply+5V_STB through resistance R 2 with its diode connected in parallel D4, and another road is through capacitor C D4 ground connection; The base stage of triode Q2 is connected to the MUTE end through resistance R 4; The grounded emitter of triode Q2.Control signal is MUTE, and high level is effective.Control logic is following: triode Q2 conducting when MUTE is high level; And then triode Q1 conducting; Power supply+5V_STB is through triode Q1, resistance R 1, diode D1, and resistance R 5, R6 inject base current to triode Q3, Q4 respectively, triode Q3, Q4 conducting; Audio signal OUT _ L and OUT_R are reached initiatively quiet effect by clamp.
The shutdown impact noise is eliminated control circuit, comprises resistance R 7, R8, triode Q5, capacitor C D1, diode D2; The ground level of triode Q5 is connected to power supply VCC5V through resistance R 8; The collector electrode of triode Q5 is connected respectively to the public part and the said start impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q5 divides two-way, and one the tunnel connects diode D2 negative electrode, and another road is connected to capacitor C D1 anode through resistance R 7; Capacitor C D1 minus earth; Diode D2 anode is connected to power supply VCC5V.During start, along with the voltage rising of power supply VCC5V, to capacitor C D1 charging, stable up to power supply VCC5V, capacitor C D1 voltage is charged to the magnitude of voltage that VCC5V deducts diode D2 pressure drop to power supply VCC5V through diode D2, resistance R 7.This voltage will be as the power supply in when shutdown.Because triode Q5 base voltage is all the time greater than emitter voltage, triode Q5 ends, and mute circuit is failure to actuate.During shutdown; Voltage decline along with power supply VCC5V; Triode Q5 base voltage begins less than emitter voltage, and capacitor C D1 begins discharge through resistance R 7, triode Q5, resistance R 8, and this discharging current is input to mute circuit through diode D1 after triode Q5 amplifies.Mute circuit is accomplished mute function.Along with capacitor C D1 voltage bleed off arrives zero, the shutdown noise is over and done with, and capacitor C D1 accomplished and discharged this moment, and charging current is zero, and triode Q5 ends.Mute circuit withdraws from mute function.
The start impact noise is eliminated control circuit, comprises triode Q6, diode D3, resistance R 9, resistance R 10, capacitor C D2; Triode Q6 collector electrode is connected to the public part and the said shutdown impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q6 is connected to power supply VCC12V; The base stage of triode Q6 connects resistance R 9; Resistance R 9 other ends divide two-way, the one road be connected to diode D3 anode and with its parallel resistor R10, the one tunnel connects capacitor C D2 anode; Diode D3 negative electrode and receive power supply VCC12V with its parallel resistor R10; Capacitor C D2 minus earth.During start, along with the voltage rising of power supply VCC12V, because capacitor C D2 is a capacitor, voltage can not suddenly change, and to capacitor C D2 charging, this charging current is input to mute circuit through diode D1 to VCC12V after triode Q6 amplifies through triode Q6, resistance R 9.Mute circuit is accomplished mute function.Along with stablizing of VCC12V, start-up noises is over and done with, and this moment, capacitor C D2 accomplished charging, and charging current is zero, and triode Q6 ends.Mute circuit withdraws from mute function.
The utility model impact noise of no longer will starting shooting is eliminated control circuit, shutdown impact noise and is eliminated the control circuit and same group of the power sharing of muting control circuit initiatively; But the start impact noise eliminates control circuit and uses VCC12, and this group power supply is that power in the set-top-box system the earliest that organized power supply; The shutdown impact noise is eliminated control circuit and is used VCC5V to be that group power supply early of electricity under the system; And the use of active muting control circuit is with the same power supply of SCM system.Such power supply design more reasonable.Initiatively muting control circuit increases capacitor C D4 and diode D4; The benefit of design is that initiatively muting control circuit also can play effect in the beginning part that system powers on like this; As long as SCM system is come together, just can play quiet effect, general set-top-box system all can use the single-chip microcomputer mini system; Be used for button start, infrared function or the like; SCM system regular software function is fairly simple, and system gets up than comparatively fast, can remedy the start impact noise and eliminate defective of a specified duration inadequately of quiet duration of control circuit.The start impact noise is eliminated control circuit increases resistance R 10, and the purpose of design is to eliminate the defective of circuit like this, if do not add resistance R10; Occur under the situation of fluctuation at the VCC12V of system; Quiet when system will have, not quiet sometimes, circuit reliability is relatively poor.Increase resistance R 10, guarantee that the cathode voltage of capacitor C D2 can reach with power supply VCC12V, occur at the VCC12V power supply under the situation of fluctuation, also can not occur unnecessary quietly, the reliability of circuit has strengthened.
Claims (2)
1. network edition STB mute circuit is characterized in that: comprise initiatively muting control circuit, start impact noise elimination control circuit, shutdown impact noise elimination control circuit, and the public part of mute circuit; Said active muting control circuit, start impact noise are eliminated control circuit, the shutdown impact noise is eliminated control circuit and is connected with the public part of said mute circuit respectively; Said active muting control circuit connects said shutdown impact noise and eliminates control circuit; Said shutdown impact noise is eliminated control circuit and is connected said start impact noise elimination control circuit.
2. network edition STB mute circuit as claimed in claim 1 is characterized in that:
The public part of said mute circuit comprises diode D1, resistance R 5, R6, triode Q3, Q4; Two anodes of said diode D1 connect said active muting control circuit respectively, said start impact noise is eliminated control circuit, said shutdown impact noise elimination control circuit; The negative electrode of said diode D1 divides two-way to connect resistance R 5 and resistance R 6 respectively; Resistance R 5 other ends connect the base stage of triode Q3, the base stage that resistance R 6 other ends connect triode Q4; The collector electrode of triode Q3 is connected to audio signal output end; The collector electrode of triode Q4 also is connected to audio signal output end; The equal ground connection of the emitter of triode Q3, Q4;
Said active muting control circuit comprises resistance R 1, R2, R3, R4, triode Q1, Q2, diode D4, capacitor C D4; The emitter of triode Q1 is connected to system power supply; The collector electrode of triode Q1 is connected to the public part of said mute circuit through resistance R 1; The base stage of triode Q1 divides three the tunnel, the one tunnel to be connected to the collector electrode of triode Q2 through resistance R 3, and another road is connected to system power supply+5V_STB through resistance R 2 with its diode connected in parallel D4, and another road is through capacitor C D4 ground connection; The base stage of triode Q2 is connected to the MUTE end through resistance R 4; The grounded emitter of triode Q2;
Said shutdown impact noise is eliminated control circuit, comprises resistance R 7, R8, triode Q5, capacitor C D1, diode D2; The ground level of triode Q5 is connected to power supply VCC5V through resistance R 8; The collector electrode of triode Q5 is connected respectively to the public part and the said start impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q5 divides two-way, and one the tunnel connects diode D2 negative electrode, and another road is connected to capacitor C D1 anode through resistance R 7; Capacitor C D1 minus earth; Diode D2 anode is connected to power supply VCC5V;
Said start impact noise is eliminated control circuit, comprises triode Q6, diode D3, resistance R 9, resistance R 9, capacitor C D2; Triode Q6 collector electrode is connected to the public part and the said shutdown impact noise of said mute circuit and eliminates control circuit; The emitter of triode Q6 is connected to power supply VCC12V; The base stage of triode Q6 connects resistance R 9; Resistance R 9 other ends divide two-way, the one road be connected to diode D3 anode and with its parallel resistor R10, the one tunnel connects capacitor C D2 anode; Diode D3 negative electrode and receive power supply VCC12V with its parallel resistor R10; Capacitor C D2 minus earth.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205721484U CN202475675U (en) | 2011-12-30 | 2011-12-30 | Network type set top box silencing circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011205721484U CN202475675U (en) | 2011-12-30 | 2011-12-30 | Network type set top box silencing circuit |
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| Publication Number | Publication Date |
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| CN202475675U true CN202475675U (en) | 2012-10-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011205721484U Expired - Lifetime CN202475675U (en) | 2011-12-30 | 2011-12-30 | Network type set top box silencing circuit |
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| CN (1) | CN202475675U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102572562A (en) * | 2011-12-30 | 2012-07-11 | 福建星网视易信息***有限公司 | Muting circuit of network-version STB (set top box) |
-
2011
- 2011-12-30 CN CN2011205721484U patent/CN202475675U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102572562A (en) * | 2011-12-30 | 2012-07-11 | 福建星网视易信息***有限公司 | Muting circuit of network-version STB (set top box) |
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Legal Events
| Date | Code | Title | Description |
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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: 20121003 |