CN103024632B - A kind of noise reduction device of earphone - Google Patents
A kind of noise reduction device of earphone Download PDFInfo
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- CN103024632B CN103024632B CN201210586310.7A CN201210586310A CN103024632B CN 103024632 B CN103024632 B CN 103024632B CN 201210586310 A CN201210586310 A CN 201210586310A CN 103024632 B CN103024632 B CN 103024632B
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Abstract
The present invention discloses a kind of noise reduction device of earphone, and this noise reduction device of earphone comprises earphone socket and pilot circuit, and earphone socket comprises detector switch; The bottom of earphone socket is located at by detector switch; When detector switch is touched at headset plug insertion and top, detector switch sends the first signal to pilot circuit; When headset plug extracts earphone socket and top is separated with described detector switch, detector switch sends second signal to pilot circuit; Pilot circuit is not when headset plug inserts earphone socket, and the power amplifier of control audio-frequency apparatus is in mute state; When receiving the first signal that detector switch sends, the biased voltage of the Mike of control earphone socket is first stablized, and transfers playback state after the power amplifier of audio-frequency apparatus to; When receiving the second signal that detector switch sends, the power amplifier of control audio-frequency apparatus first transfers mute state to, stable after the biased voltage of Mike. The technical scheme of the present invention avoids the plosive emergence period of earphone socket, greatly improves practical comfort level.
Description
Technical field
The present invention relates to earphone and fall technical field of making an uproar, in particular to a kind of noise reduction device of earphone.
Background technology
The exact connect ion of existing earphone socket each terminal of plug and socket that has been simple realization, although detector switch have issued earphone insertion signal during use, but it is not now that each terminal in earphone socket contacts stable state with the respective electrode in headset plug, does not meet insertion detection function completely; When headset plug is extracted, detector switch does not also detect extracts operation, and each terminal in earphone socket and the respective electrode in headset plug just disconnect, and detector switch can not accomplish the effect detected in advance. And plug noise is not processed by existing earphone socket, in headset plug insertion process, the connection of Mike's terminal and Mike's electrode can cause the level sudden change from high to low of the biased voltage instantaneous of Mike, in headset plug withdrawal process, can there is sudden change from low to high in the biased voltage of Mike, although this sudden change signal time length is very short, but output to earphone after monitoring amplification circuit, thus produce ear-piercing plosive, it is that Consumer's Experience is not good. The following is the analysis that prior art is produced the reason of plosive and carries out:
Fig. 1 is the schematic diagram that in prior art, earphone plug plosive produces. Mike's electrode 501 of 1 headset plug coordinates with Mike's terminal 303 of earphone socket in the drawings, and the ground-electrode 502 of headset plug coordinates with the ground terminal 304 of earphone socket. see Fig. 1, headset plug insertion process, namely the process that in Fig. 1, Mike's electrode 501 of headset plug coordinates with Mike's terminal 303 of earphone socket, the process that the ground-electrode 502 of headset plug coordinates with the ground terminal 502 of earphone socket, in the process, Mike's terminal 303 of earphone socket does not also reliably contact with Mike's electrode 501 of headset plug, now continue insertion and will cause detector switch action, monitoring amplification circuit is in normal operation, do not meet insertion detection function completely, the withdrawal process of headset plug, namely the process that Mike's electrode 501 of the headset plug in Fig. 1 disconnects with Mike's terminal 303 of earphone socket, the process that the ground-electrode 502 of headset plug disconnects with the ground terminal 304 of earphone socket, in the process, when detector switch does not also detect that dial-out operates, Mike's terminal 303 just disconnects with Mike's electrode 501, detector switch does not have the effect detected in advance, thus the plug noise shown in Fig. 1 can be produced, plug noise forms plosive by the amplification of the power amplifier 103 of audio-frequency apparatus.
The signal that usual microphone produces is very faint general at about 10mV, and plosive signal generally can reach 1000mV, although but the equipment that so there is no to take measures output to plosive time of earphone very short can be very ear-piercing.
Summary of the invention
In view of the above problems, it is proposed that the present invention is to provide a kind of a kind of noise reduction device of earphone overcoming the problems referred to above or solving the problem at least in part.
For achieving the above object, the technical scheme of the present invention is achieved in that
The present invention discloses a kind of noise reduction device of earphone, and this device described comprises earphone socket and pilot circuit, and described earphone socket comprises detector switch; Described detector switch is arranged at the bottom of described earphone socket; The input terminus of described pilot circuit is connected with detector switch; The output terminal of described pilot circuit is connected with the quiet control port of the power amplifier of audio-frequency apparatus;
When the headset plug coordinated with described earphone socket inserts described earphone socket, and when described detector switch is touched at the top of headset plug, described detector switch sends the first signal to pilot circuit; When described headset plug extracts described earphone socket, and when the top of described headset plug is separated with described detector switch, described detector switch sends second signal to pilot circuit;
Pilot circuit, for when described headset plug does not insert described earphone socket, the power amplifier of control audio-frequency apparatus is in mute state; For when receiving the first signal that detector switch sends, the biased voltage of Mike controlling described earphone socket first rises to rated value by zero and stablizes, and transfers playback state after the power amplifier of audio-frequency apparatus to; For when receiving the second signal that detector switch sends, the power amplifier of control audio-frequency apparatus first transfers mute state to, after the biased voltage of Mike, it is returned to zero by rated value.
Can selection of land, described detector switch comprises: the first detector switch terminal and the 2nd detector switch terminal;
Wherein the first detector switch terminal maintains static, and the 2nd detector switch terminal is movable;
When described detector switch is touched at the top of described headset plug, the 2nd detector switch terminal is separated with the first detector switch terminal;
When the top of described headset plug is separated with described detector switch, the 2nd detector switch terminal merges with the first detector switch terminal.
Can selection of land, described earphone socket also comprises: Mike's terminal;
Described Mike's terminal extends to the insertion port near earphone socket.
Can selection of land, described earphone socket also comprises: ground terminal and sound channel terminal; Wherein, the ground-electrode of described ground terminal and headset plug coordinates; The sound channel electrode of described sound channel terminal and headset plug coordinates; Mike's electrode of Mike's terminal and headset plug coordinates.
Can selection of land, described Mike's terminal, ground terminal, sound channel terminal, the first detector switch terminal and the 2nd detector switch terminal are shell fragment.
Can selection of land, described pilot circuit comprises Mike's bias voltage control circuit and power amplification control circuit.
Can selection of land, described Mike's bias voltage control circuit comprises resistance six, PNP triode one, power supply four, electric capacity five, resistance four and resistance eight;
One end of resistance six is connected with one end of resistance eight, the other end ground connection of resistance eight, and the tie point between resistance six and resistance eight is also for the Mike's terminal connection with described earphone socket; The other end of resistance six is connected with the collector electrode of PNP triode one; The emtting electrode of PNP triode one is connected with the positive pole of power supply four, the negative pole ground connection of power supply four; The base stage of PNP triode one is connected with one end of electric capacity five, the other end ground connection of electric capacity five; The base stage of PNP triode one also one end with resistance four is connected; The other end of resistance four is for being connected with the detector switch of earphone socket, and the other end of resistance four is also connected with one end of power amplification control circuit.
Can selection of land, described power amplification control circuit comprises: resistance two, electric capacity four, NPN triode two, resistance 12, resistance one, electric capacity one, NPN triode four, resistance three, resistance seven, resistance 11 and power supply one; One end of resistance two is connected with the other end of resistance four, and one end of resistance two also one end with resistance 12 is connected, and one end of resistance two also one end with resistance one is connected; The other end of resistance 12 is connected with one end of resistance seven, and the other end of resistance seven is connected with the collector electrode of NPN triode two, and the base stage of NPN triode two is connected with the other end of resistance one; The other end of resistance one also one end with electric capacity one is connected, the other end ground connection of electric capacity one; The other end of resistance 12 also positive pole with power supply one be connected, the negative pole ground connection of power supply one; The other end of resistance 12 also one end with resistance 11 is connected, and the other end of resistance 11 is connected with one end of resistance three, the other end ground connection of resistance three, the other end of resistance 11 also collector electrode with NPN triode four be connected; Tie point between the collector electrode of NPN triode four and resistance three is for the quiet control end that connects the power amplifier of audio-frequency apparatus; The grounded emitter of NPN triode four; The base stage of NPN triode four is connected with the other end of resistance two; The base stage of NPN triode four also one end with electric capacity four is connected, the other end ground connection of electric capacity four; The base stage of NPN triode four also emtting electrode with NPN triode two be connected.
Can selection of land, described electric capacity four and electric capacity five have identical capacitance; The capacitance of electric capacity one is much smaller than electric capacity four; The resistance of resistance two is greater than resistance four; The resistance of resistance seven is less than resistance four;
Each electric capacity discharges when headset plug inserts, and NPN triode two first ends, PNP triode one secondly conducting, NPN triode four final coutoff;
Each electric capacity charges when headset plug is extracted, the first conducting of NPN triode two, NPN triode four secondly conducting, PNP triode one final coutoff.
Can selection of land, described electric capacity four and electric capacity five capacitance are 10 �� F; The capacitance of electric capacity one is 100nF; The resistance of resistance two is 500K ��; The resistance of resistance four is the resistance 1K �� of 100K ��, resistance seven.
This kind of technical scheme of the present invention redesigns the detector switch of earphone socket and the position of Mike's terminal, headset plug insertion process makes each terminal of headset plug contact with the respective electrode of earphone socket stable after, make detector switch action again, send, to pilot circuit, the first signal that plug inserts completely; Dial-out process first makes detector switch action, after sending, to pilot circuit, the second signal transfering to prompting each terminal of earphone socket again each electrode with headset plug disconnect respectively, make the working order of the power amplifier of the first signal that pilot circuit sends according to detector switch or second signal control audio-frequency apparatus, thus avoid the emergence period of plosive, substantially increase the comfort of user.
Accompanying drawing explanation
Fig. 1 is the schematic diagram that in prior art, earphone plug plosive produces;
Fig. 2 is the functional block diagram that the embodiment of the present invention eliminates earphone plug noise;
Fig. 3 is the top TV structure figure of the standard level Four earphone socket of the embodiment of the present invention;
Fig. 4 is the side block diagram of the standard level Four earphone socket of the embodiment of the present invention;
Fig. 5 is each electrode schematic diagram of standard headphone plug of the embodiment of the present invention;
Fig. 6 is the schematic circuit diagram of the pilot circuit of embodiment of the present invention earphone socket.
Embodiment
Based on the problem that the plosive described in background technology produces, it is proposed that technical solution of the present invention, the condition that earphone socket should meet in the inventive solutions is:
In plug insertion process, each terminal in earphone socket first contacts with the respective electrode of headset plug after stablizing, detector switch is action again, and namely in plug insertion process, detector switch wants sluggish other terminals in earphone socket to contact the stable time with the respective electrode of headset plug opening time;
In plug withdrawal process, the first action of the detector switch of earphone socket, other terminals in earphone socket again respective electrode with headset plug disconnect, namely in plug withdrawal process, detector switch opening time will time of disconnecting of the respective electrode of the terminal of other in earphone socket and headset plug in advance.
Not using and signalling channel closed during equipment, in earphone insertion process, the electrode contact waiting noise to produce each terminal of earphone socket and headset plug opens signalling channel after stablizing again;
Know in advance and namely noise will occur, then cut off signalling channel at once.
Based on the condition that the technical solution of the present invention of above-mentioned proposition should meet, the technical scheme of the present invention is:
Detector switch extends to direction of insertion, strengthens the distance between detector switch and Mike's terminal;
Suitably increasing the length of Mike's terminal, contact Mike's electrode of headset plug when reaching insertion in advance, detector switch is action again, detector switch first action during dial-out, the effect that Mike's electrode of headset plug disconnects with Mike's terminal of earphone socket again;
The parameter of electric capacity and resistance in design con-trol circuit so that headset plug is before insertion process, and the power amplifier of pilot circuit control audio-frequency apparatus is in mute state; Headset plug insertion earphone socket, and when touching detector switch, during detector switch action, the biased voltage of Mike of pilot circuit control earphone socket first rises to rated value by zero and stablizes, playback state is transferred to, and the power amplifier of audio-frequency apparatus is in the time sluggish time produced in plug noise of playback state after the power amplifier of audio-frequency apparatus; Headset plug transfers to earphone socket, and during detector switch action, the power amplifier of pilot circuit control audio-frequency apparatus first transfers mute state to, is returned to zero by rated value after the biased voltage of Mike.
Specifically, a kind of noise reduction device of earphone disclosed by the invention, this device comprises earphone socket and pilot circuit, and earphone socket comprises detector switch; Detector switch is arranged at the bottom (i.e. the end of earphone socket) of earphone socket; The input terminus of pilot circuit is connected with detector switch; The output terminal of pilot circuit is connected with the quiet control port of the power amplifier of audio-frequency apparatus; When the headset plug insertion earphone socket coordinated with earphone socket, and when detector switch is touched at the top of headset plug, detector switch sends the first signal to pilot circuit; When headset plug extracts earphone socket, and when the top of headset plug is separated with detector switch, detector switch sends second signal to pilot circuit; Pilot circuit, for when headset plug does not insert described earphone socket, the power amplifier of control audio-frequency apparatus is in mute state, for when receiving the first signal that detector switch sends, the biased voltage of the Mike of control earphone socket first rises to rated value by zero and stablizes, and transfers playback state after the power amplifier of audio-frequency apparatus to, for when receiving the second signal that detector switch sends, the power amplifier of control audio-frequency apparatus first transfers mute state to, is returned to zero by rated value and stablizes after the biased voltage of Mike.
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.
See Fig. 2, for the embodiment of the present invention eliminates the functional block diagram of earphone plug noise.
See Fig. 2, the noise reduction device of earphone in the embodiment of the present invention comprises earphone socket 200 and pilot circuit 202. Earphone socket 200 comprises detector switch 201; Detector switch 201 is arranged at the bottom of earphone socket 200; The input terminus of pilot circuit 202 is connected with detector switch 201; The output terminal of pilot circuit 202 is connected with the power amplifier 103 of audio-frequency apparatus; When the headset plug 204 coordinated with earphone socket 200 inserts earphone socket 200, and when described detector switch 201 is touched at the top of headset plug 204, detector switch 201 sends the first signal to pilot circuit 202; When headset plug 204 extracts earphone socket, and when the top of headset plug 204 is separated with detector switch 201, detector switch 201 sends second signal to pilot circuit 202; Pilot circuit 202, for when headset plug 204 does not insert earphone socket 200, the power amplifier 103 of control audio-frequency apparatus is in mute state; For when receiving the first signal that detector switch 201 sends, the biased voltage of the Mike of control earphone socket 200 first rises to rated value by zero and stablizes, and transfers playback state to after the power amplifier 103 of audio-frequency apparatus; For when receiving detection and open the second signal that 201 passes send, the power amplifier 103 of control audio-frequency apparatus first transfers mute state to, it is returned to zero by rated value after the biased voltage of Mike and stablizes. In an embodiment of the present invention, pilot circuit 202 is connected with the quiet control port of the power amplifier 103 of audio-frequency apparatus.
Owing to detector switch in the embodiment of the present invention is placed in the bottom of earphone socket, thus in headset plug insertion process, other terminals can first contact with the respective electrode of headset plug, other terminals at earphone socket contact in stable process with the respective electrode of headset plug, the sudden change of biased voltage can be caused, and then have the generation of plug noise, but the power amplifier that pilot circuit makes audio-frequency apparatus is in mute state, although thus there being plug noise to produce, but owing to the power amplifier of audio-frequency apparatus is in mute state, so earphone can not hear plosive, subsequently, other terminals of earphone socket contact stable with the respective electrode of headset plug, plug noise disappears, now detector switch sends the first signal, in an embodiment of the present invention, this first signal is specially low level signal, the power amplifier that pilot circuit controls audio-frequency apparatus after receiving this low level signal is converted to working order from mute state, although now earphone can hear sound, but plug noise disappears, so plosive can not be heard. in dial-out process, the first action of detector switch, send second signal and it is specially high level signal here to pilot circuit, pilot circuit is after receiving this high level signal, the power amplifier of control audio-frequency apparatus transfers mute state to from working order, other terminals of earphone socket again respective electrode with headset plug disconnect, the moment disconnected, the sudden change of biased voltage can be caused, and then have the generation of plug noise, although now there being plug noise to produce, but owing to the power amplifier of audio-frequency apparatus is in mute state, sound be can't hear by earphone, so plosive also be can't hear by earphone.
The standard level Four earphone socket 200 that Fig. 3 is the embodiment of the present invention pushes up TV structure figure.
See Fig. 3, in this earphone socket 200, detector switch comprises: the first detector switch terminal 301 and the 2nd detector switch terminal 302; Wherein the first detector switch terminal 301 maintains static, and the 2nd detector switch end 302 is movable; When detector switch is touched at the top of headset plug, the 2nd detector switch terminal 302 is separated with the first detector switch terminal 301; When extracting headset plug, the top of headset plug is separated with detector switch, and the 2nd detector switch terminal 302 merges with the first detector switch terminal 301.
In an embodiment of the present invention, the first signal is low level signal, and second signal is high level signal; In an initial condition, the 2nd detector switch terminal 302 is in the first detector switch terminal 301 and merges state, and now pilot circuit makes the power amplifier of audio-frequency apparatus be in mute state. When headset plug 204 inserts, the 2nd detector switch terminal 302 turns into being separated from merging with the state of the first detector switch terminal 301, and detector switch 201 action, sends low level signal to pilot circuit 202; When headset plug 204 is transferred to, the 2nd detector switch terminal 302 turns into merging from being separated with the state of the first detector switch terminal 301, and detector switch 201 action, sends high level signal to pilot circuit 202.
Fig. 4 is the side block diagram of the standard level Four earphone socket 200 of the embodiment of the present invention.
See Fig. 3 and Fig. 4, this kind of earphone socket 200 disclosed by the invention also comprises: Mike's terminal 303; See Fig. 4, Mike's terminal 303 extends to the insertion port near earphone socket. Owing to Mike's terminal 303 to be extended to the insertion port near earphone socket, thus make when earphone inserts, Mike's electrode of headset plug is stablized prior to Mike's termination contact of earphone socket, and detector switch is action again, namely sends low level signal to pilot circuit; When earphone is extracted, the first action of detector switch, namely sends high level signal to pilot circuit, Mike's electrode of headset plug is that Mike's terminal of earphone socket disconnects, and avoids the emergence period of plosive, it is to increase the comfort of user.
In this manual, other terminals of the earphone socket mentioned contact stable with the respective electrode of headset plug, mainly refer to that Mike's terminal of earphone socket and Mike's electrode contact of headset plug are stablized; The meeting mentioned causes the sudden change of biased voltage, mainly the sudden change of the biased voltage of Mike; Other terminals of earphone socket again respective electrode with headset plug disconnect, the Mike's terminal mainly referring to earphone socket again Mike's electrode with headset plug disconnect.
Fig. 5 is each electrode schematic diagram of standard headphone plug of the embodiment of the present invention.
See Fig. 3 and Fig. 5, this kind of earphone socket of the embodiment of the present invention also comprises: ground terminal 304 and sound channel terminal 305; Wherein, the ground-electrode 502 of ground terminal 304 and headset plug 204 coordinates; The sound channel electrode 503 of sound channel terminal 305 and headset plug 204 coordinates; Mike's electrode 501 of Mike's terminal 303 and headset plug 204 coordinates. In Figure 5, label 504 is the top of headset plug 204.
See Fig. 3, in this earphone socket, Mike's terminal 303, ground terminal 304, sound channel terminal 305, first detector switch terminal 301 and the 2nd detector switch terminal 302 are shell fragment.
Fig. 6 is the schematic circuit diagram of the pilot circuit of embodiment of the present invention earphone socket.
See Fig. 6, in the earphone socket of the embodiment of the present invention, pilot circuit comprises Mike's bias voltage control circuit 601 and power amplification control circuit 602.
See Fig. 6, executing in the present invention in the pilot circuit of earphone socket of example, Mike's bias voltage control circuit 601 comprises resistance R6, PNP triode Q1, power supply V4, electric capacity C5 and resistance R4; One end of resistance R6 is connected with one end of resistance R8, the other end ground connection of resistance R8, and the tie point between resistance R6 and resistance R8 is also for the Mike's terminal connection with earphone socket; The other end of resistance R6 is connected (node 6 in Fig. 6) with the collector electrode of PNP triode Q1; The emtting electrode of PNP triode Q1 is connected with the positive pole of power supply V4 (node 7 in Fig. 6), the negative pole ground connection of power supply V4; The base stage of PNP triode Q1 is connected with one end of electric capacity C5 (node 3 in Fig. 6), the other end ground connection of electric capacity C5; The base stage of PNP triode Q1 also one end with resistance R4 is connected; The other end of resistance R4 is for being connected with earphone socket detector switch, here be specifically connected (node 10 in Fig. 6) with J1A, wherein, J1A is the equivalent switch of headset plug and earphone socket state, when headset plug inserts earphone socket, J1A closes, and when headset plug transfers to earphone socket, J1A disconnects; The other end of resistance R4 also one end with power amplification control circuit 602 is connected.
Executing in the present invention in the pilot circuit of earphone socket of example, power amplification control circuit 602 comprises resistance R2, electric capacity C4, NPN triode Q2, resistance R12, resistance R1, electric capacity C1, NPN triode Q4, resistance R3, resistance R7, resistance R11 and power supply V1; One end of resistance R2 for being connected with detector switch, one end of resistance R2 also the other end with resistance R4 be connected, one end of resistance R2 also one end with resistance R12 is connected, and one end of resistance R2 also one end with resistance R1 is connected; The other end of resistance R12 is connected with one end of R7, and the other end of resistance R7 is connected with the collector electrode of NPN triode Q2 (node 1 in Fig. 6), and the base stage of NPN triode Q2 is connected with the other end of resistance R1; The other end of resistance R1 is also connected with one end of electric capacity C1 (node 2 in Fig. 6), the other end ground connection of electric capacity C1; The other end of resistance R12 also positive pole with power supply V1 be connected, the negative pole ground connection of power supply V1; The other end of resistance R12 is also connected (node 5 in Fig. 6) with one end of resistance R11, the other end of resistance R11 is connected with one end of resistance R3, the other end ground connection of resistance R3, the other end of resistance R11 is also connected (node 4 in Fig. 6) with the collector electrode of NPN triode Q4; Tie point between the collector electrode of NPN triode Q4 and resistance R3 is for the quiet control end that connects the power amplifier of audio-frequency apparatus; The grounded emitter of NPN triode Q4; The base stage of NPN triode Q4 is connected with the other end of resistance R2; The base stage of NPN triode Q4 is also connected with one end of electric capacity C4 (node 9 in Fig. 6), the other end ground connection of electric capacity C4; The base stage of NPN triode Q4 also emtting electrode with NPN triode Q2 be connected.
In this kind of earphone socket disclosed in the embodiment of the present invention, electric capacity C4 and electric capacity C5 has identical capacitance; The capacitance of electric capacity C1 is much smaller than electric capacity C4; The resistance of resistance R2 is greater than resistance R4; The resistance of resistance R7 is much smaller than R4; In insertion headset plug process, electric capacity C1, electric capacity C4, electric capacity C5 are when discharging, and NPN triode Q2 first ends, PNP triode Q1 secondly conducting, NPN triode Q4 final coutoff; Transfer in headset plug process, electric capacity C1, electric capacity C4, electric capacity C5 when charging, the first conducting of NPN triode Q2, NPN triode Q4 secondly conducting, PNP triode Q1 final coutoff.
In this kind of earphone socket disclosed in the embodiment of the present invention, electric capacity C4 and electric capacity C5 capacitance are 10 �� F, the capacitance of electric capacity C1 is 100nF, the resistance of resistance R2 is 500K ��, the resistance of resistance R4 is 100K ��, the resistance 1K �� of resistance R7, the resistance of resistance R1 is 200K ��, the resistance of resistance R12 is 100K ��, the resistance of resistance R11 is 100K ��, the resistance of resistance R3 is 190K ��, the resistance of resistance R6 is 3K ��, the resistance of resistance R8 is 5.6K ��, in figure 6, resistance R5 represents the equivalent resistance of headset plug, R5 and J1A connects (node 11 in Fig. 6), the resistance of resistance R5 is 32 ��, power supply V1 is 5V, power supply V4 is 2V, the model of NPN triode Q4 and NPN triode Q2 is BC847B, the model of PNP triode Q1 is BC857C.
In an embodiment of the present invention, when exporting lower level to the quiet port of the power amplifier of audio-frequency apparatus, the power amplifier of audio-frequency apparatus is in mute state; When exporting high level to the quiet port of the power amplifier of audio-frequency apparatus, the power amplifier of audio-frequency apparatus is in running order.
The principle of work of foregoing circuit is as follows:
When headset plug does not insert earphone socket, namely J1A disconnects, PNP triode Q1 is in off condition, microphone bias voltage exports as 0V, NPN triode Q2 and NPN triode Q4 saturation conduction, when NPN triode Q4 saturation conduction, lower level is exported to the quiet port of the power amplifier of audio-frequency apparatus, power amplifier is in mute state, if now inserting headset plug, namely J1A closes, before detector switch sends low level signal, the plug noise of each electrode instability contact cannot be sent by power amplifier owing to the power amplifier of audio-frequency apparatus is in mute state, and the voltage of each electrode of earphone socket is very little also can not cause friction noise, when after detector switch action, low level signal is sent to pilot circuit, each electrode is stable contact, now the electric capacity of each transistor base starts electric discharge, the calculation formula t=R of the discharge and recharge time according to electric capacity �� C calculates, when triode discharges, t1=R1 �� C1 discharge time of electric capacity C1, (R5 is relative to R1, R2 and R4 is very little, can ignore) t2=R2 �� C4 discharge time of electric capacity C4, t3=R4 �� C5 discharge time of electric capacity C5, calculate, electric capacity C1 discharges the fastest, electric capacity C5 is secondly, C4 is the slowest for electric capacity, thus NPN triode Q2 ends the soonest, PNP triode Q1 secondly conducting, the NPN triode the slowest conducting of Q4, this time missionary society cause the biased voltage of Mike first stable after power amplifier just normal playback, the plug noise that the fluctuation of the biased voltage of such Mike produces also can not export from the power amplifier of audio-frequency apparatus. during earphone withdrawal process, detector switch sends high level signal, now each triode can be charged, still calculation formula t=R �� C according to discharge and recharge time of electric capacity calculates, different with electric discharge speed, duration of charging t1=R1 �� the C1 of electric capacity C1, duration of charging is the shortest, therefore electric capacity C1 is full of at first, after the electric capacity C1 of NPN triode Q2 base stage is first full of, NPN triode Q2 conducting, such NPN triode Q2 emtting electrode can give the electric capacity C4 rapid charge of Q4 base stage place, so time electric capacity C4 duration of charging t2=R7 �� C4, and the duration of charging of electric capacity C5 is still t3=R4 �� C5, calculating electric capacity C1 charges the fastest, electric capacity C4 is secondly, C5 is the slowest for electric capacity, therefore the first conducting of NPN triode Q2, then NPN triode Q4 conducting, last PNP triode Q1 ends, this sequential relation will make the quiet biased voltage of then Mike that first starts of the power amplifier of audio-frequency apparatus make zero again, avoid the plug noise that the biased voltage fluctuation of Mike produces, it is all not charged that such earphone continues each electrode of socket in withdrawal process, also friction noise can not be produced.
In sum, the technical scheme tool of the present invention has the following advantages:
1, owing to detector switch is placed in the bottom of earphone socket by the technical scheme of the present invention, and Mike's terminal is extended to the insertion port of close earphone socket, when headset plug is inserted, each terminal of earphone socket first contacts stable with the respective electrode of headset plug, detector switch is action again, headset plug when extracting, the first action of detector switch, each terminal of earphone socket again respective electrode with headset plug disconnect, avoid the generation of plosive.
2, owing to the technical scheme of the present invention is to the design of the electric capacity of pilot circuit and resistance parameter, make this circuit after coordinating with detector switch, when earphone inserts, sequential according to triode ON is different, power amplifier just playback after making the biased voltage of Mike first stable, when earphone is extracted, makes that power amplifier is quiet first to be started, the biased voltage of Mike is stablized again, avoids the generation of plosive.
The foregoing is only this better embodiment, it is not intended to limit protection scope of the present invention. All do within the spirit and principles in the present invention any amendment, equivalent replacement, improvement etc., be all included in protection scope of the present invention.
Claims (8)
1. a noise reduction device of earphone, it is characterised in that, this device described comprises earphone socket and pilot circuit, and described earphone socket comprises detector switch; Described detector switch is arranged at the bottom of described earphone socket; The input terminus of described pilot circuit is connected with detector switch; The output terminal of described pilot circuit is connected with the quiet control port of the power amplifier of audio-frequency apparatus;
When the headset plug coordinated with described earphone socket inserts described earphone socket, and when described detector switch is touched at the top of headset plug, described detector switch sends the first signal to pilot circuit; When described headset plug extracts described earphone socket, and when the top of described headset plug is separated with described detector switch, described detector switch sends second signal to pilot circuit;
Pilot circuit, for when described headset plug does not insert described earphone socket, the power amplifier of control audio-frequency apparatus is in mute state; For when receiving the first signal that detector switch sends, the biased voltage of Mike controlling described earphone socket first rises to rated value by zero and stablizes, and transfers playback state after the power amplifier of audio-frequency apparatus to; For when receiving the second signal that detector switch sends, the power amplifier of control audio-frequency apparatus first transfers mute state to, after the biased voltage of Mike, it is returned to zero by rated value;
Wherein, described pilot circuit comprises Mike's bias voltage control circuit and power amplification control circuit;
Described Mike's bias voltage control circuit comprises resistance six, PNP triode one, power supply four, electric capacity five, resistance four and resistance eight;
One end of resistance six is connected with one end of resistance eight, the other end ground connection of resistance eight, and the tie point between resistance six and resistance eight is also for the Mike's terminal connection with described earphone socket; The other end of resistance six is connected with the collector electrode of PNP triode one; The emtting electrode of PNP triode one is connected with the positive pole of power supply four, the negative pole ground connection of power supply four; The base stage of PNP triode one is connected with one end of electric capacity five, the other end ground connection of electric capacity five; The base stage of PNP triode one also one end with resistance four is connected; The other end of resistance four is for being connected with the detector switch of earphone socket, and the other end of resistance four is also connected with one end of power amplification control circuit.
2. device according to claim 1, it is characterised in that, described detector switch comprises: the first detector switch terminal and the 2nd detector switch terminal;
Wherein the first detector switch terminal maintains static, and the 2nd detector switch terminal is movable;
When described detector switch is touched at the top of described headset plug, the 2nd detector switch terminal is separated with the first detector switch terminal;
When the top of described headset plug is separated with described detector switch, the 2nd detector switch terminal merges with the first detector switch terminal.
3. device according to claim 2, it is characterised in that, described earphone socket also comprises: Mike's terminal;
Described Mike's terminal extends to the insertion port near earphone socket.
4. device according to claim 3, it is characterised in that, described earphone socket also comprises: ground terminal and sound channel terminal; Wherein, the ground-electrode of described ground terminal and headset plug coordinates; The sound channel electrode of described sound channel terminal and headset plug coordinates; Mike's electrode of Mike's terminal and headset plug coordinates.
5. device according to claim 4, it is characterised in that, described Mike's terminal, ground terminal, sound channel terminal, the first detector switch terminal and the 2nd detector switch terminal are shell fragment.
6. device according to claim 1, it is characterized in that, described power amplification control circuit comprises: resistance two, electric capacity four, NPN triode two, resistance 12, resistance one, electric capacity one, NPN triode four, resistance three, resistance seven, resistance 11 and power supply one; One end of resistance two is connected with the other end of resistance four, and one end of resistance two also one end with resistance 12 is connected, and one end of resistance two also one end with resistance one is connected; The other end of resistance 12 is connected with one end of resistance seven, and the other end of resistance seven is connected with the collector electrode of NPN triode two, and the base stage of NPN triode two is connected with the other end of resistance one; The other end of resistance one also one end with electric capacity one is connected, the other end ground connection of electric capacity one; The other end of resistance 12 also positive pole with power supply one be connected, the negative pole ground connection of power supply one; The other end of resistance 12 also one end with resistance 11 is connected, and the other end of resistance 11 is connected with one end of resistance three, the other end ground connection of resistance three, the other end of resistance 11 also collector electrode with NPN triode four be connected; Tie point between the collector electrode of NPN triode four and resistance three is for the quiet control end that connects the power amplifier of audio-frequency apparatus; The grounded emitter of NPN triode four; The base stage of NPN triode four is connected with the other end of resistance two; The base stage of NPN triode four also one end with electric capacity four is connected, the other end ground connection of electric capacity four; The base stage of NPN triode four also emtting electrode with NPN triode two be connected.
7. device according to claim 6, it is characterised in that,
Described electric capacity four and electric capacity five have identical capacitance; The ratio of the capacitance of electric capacity one and electric capacity four is less than the ratio of the resistance of resistance seven with resistance one; The resistance of resistance two is greater than resistance four; The resistance of resistance seven is less than resistance four;
Each electric capacity discharges when headset plug inserts, and NPN triode two first ends, PNP triode one secondly conducting, NPN triode four final coutoff;
Each electric capacity charges when headset plug is extracted, the first conducting of NPN triode two, NPN triode four secondly conducting, PNP triode one final coutoff.
8. device according to claim 7, it is characterised in that,
Described electric capacity four and electric capacity five capacitance are 10 �� F; The capacitance of electric capacity one is 100nF; The resistance of resistance two is 500K ��; The resistance of resistance four is the resistance 1K �� of 100K ��, resistance seven.
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| CN201210586310.7A CN103024632B (en) | 2012-12-30 | 2012-12-30 | A kind of noise reduction device of earphone |
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| CN103414984A (en) * | 2013-07-25 | 2013-11-27 | 苏州三星电子电脑有限公司 | System for eliminating explosion sound of earphones |
| CN103458342B (en) * | 2013-09-18 | 2016-08-17 | 上海贝岭股份有限公司 | A kind of circuit eliminating shutdown POP sound of audio power amplifier |
| US20170078797A1 (en) * | 2014-06-30 | 2017-03-16 | Huawei Technologies Co., Ltd. | Terminal and System Capable of Reducing Noise Generated in Process of Plugging or Unplugging Earphone |
| AU2015395527B2 (en) * | 2015-05-15 | 2018-10-18 | Huawei Technologies Co., Ltd. | Noise reduction headset setting method, terminal, and noise reduction headset |
| CN106535038A (en) * | 2015-09-15 | 2017-03-22 | 展讯通信（上海）有限公司 | Circuit and method for eliminating plug and play noise of headphone |
| CN111294685B (en) * | 2019-07-02 | 2022-02-11 | 展讯通信（上海）有限公司 | Method, device, terminal and storage medium for reducing earphone insertion noise |
| CN117278904A (en) * | 2023-11-03 | 2023-12-22 | 荣耀终端有限公司 | Earphone control circuit, earphone control method and electronic equipment |
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