CN100490345C - Power line transmission sound box system - Google Patents
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- CN100490345C CN100490345C CNB021218242A CN02121824A CN100490345C CN 100490345 C CN100490345 C CN 100490345C CN B021218242 A CNB021218242 A CN B021218242A CN 02121824 A CN02121824 A CN 02121824A CN 100490345 C CN100490345 C CN 100490345C
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Abstract
The invention relates to a power line transmission speaker system characterized by that, the transmitter comprises audio input circuit, audio filtering shaping circuit, audio modulation coding circuit, oscillation and phase-locked loop circuit, high-frequency amplification & coupling output circuit and power supply circuit. The receiving speaker is composed of high-frequency coupling and input circuit, local oscillator circuit, FM integration receiving circuit, audio signal processing circuit, power amplifier circuit, squelch circuit, stereo horn set and power supply. The invention can realize the high fidelity stereophonic transmission.
Description
Technical field
The present invention relates to a kind of sound box system, particularly a kind of power line transmission sound box system.Belong to audio class radio electronics product technical field.
Background technology
At present, the power line transmission technology is mainly used in the power line communications engineering.This be a kind of be connected on the local area network (LAN) subscriber computer by power line at local area network (LAN) inner or and WAN outlet between transmit the application technology of data.Its principle is: computer compresses packing data by software, sends on the power line by special connector, and the computer of reception is from the decoding of unpacking later on of power line received signal.Mainly be applicable to the communication between the local area network (LAN) inner computer.Shortcoming is: be subjected to disturb big, decay is big, make mistakes easily in the data transfer procedure and be blocked, and needs to encrypt, and requires the power output of transmitter bigger.
The Chinese patent communique discloses name and has been called " power line carrier frequency-modulated broadcast transmitter and receiver ", the patent No. and is " 93234182.9 ", name is called " power line carrier broadcasting transmitter and receiver ", the patent No. is " 89209064.2 ", the binomial patent of invention, their common feature is made up of transmitter and receiver, utilize power line to carry, transmitter is modulated into fm carrier signal with audio signal and is coupled on the power line, is sent on the receiver by power line.But because the unreasonable structure of these two patents, therefore have the shortcoming of two aspects: the FM signal instability that transmitter sends and can not send stereo audio signal, receiver can only be play simple broadcast singal, can not constitute stereo broadcast terminal.
Summary of the invention
The objective of the invention is to utilize existing power line network, realize the Wireless Fidelity transmission of stereo audio, undistorted reduction of audio signal and broadcast for a kind of power line transmission sound box system is provided.
Purpose of the present invention can reach by taking following measure: power line transmission sound box system, its design feature is: transmitter is by the audio frequency input circuit, the audio frequency filtering shaping circuit, the voice modulation coding circuit, vibration and phase-locked loop circuit, high frequency amplification and coupling output circuit and power circuit are formed by connecting, the input of audio frequency input circuit, output connects the source of sound output respectively, the input of audio frequency filtering shaping circuit, the input of voice modulation coding circuit, output connects the output of audio frequency filtering shaping circuit respectively, the input of vibration and phase-locked loop circuit, the input of high frequency amplification and coupling output circuit, output connects the output of vibration and phase-locked loop circuit respectively, power line, the output of power circuit connects the power input of each circuit.
With the supporting reception audio amplifier of aforementioned transmitter, its design feature is: by high-frequency coupling and input circuit, local oscillation circuit, the integrated receiving circuit of FM, audio signal processing circuit, power amplifier, squelch circuit, stereo loudspeaker group and power circuit are formed by connecting, the input of high-frequency coupling and input circuit receives high-frequency signal from power line, output connects the input of the integrated receiving circuit of FM, the input of audio signal processing circuit, output connects the output of the integrated receiving circuit of FM respectively, the input of power amplifier, the input of squelch circuit, output connects the output of power amplifier respectively, the input of stereo loudspeaker group, the output of power circuit connects the power input of each circuit.
Purpose of the present invention can also reach by taking following measure:
The audio frequency input circuit is formed by connecting by audio interface and automatic gain control circuit, audio interface is connected with external sound source, import by low level, high level is imported two groups of input interfaces and is constituted, its output connects two inputs of selector switch S, the output of switch S connects the input of automatic gain control circuit, the output of high level interface connects the input of selector switch S by amplitude limiter circuit, automatic gain control circuit mainly amplifies chip by the dual track prime of band automatic gain control and the peripheral electron element is formed by connecting, and its output connects the input of audio frequency filtering shaping circuit.
The audio frequency filtering shaping circuit is made of filter circuit, preemphasis circuit and audio frequency simulation compressor circuit, the input of filter circuit connects the output of audio frequency input circuit, the input that output connects preemphasis circuit, and the input of audio frequency simulation compressor circuit, output connect the output of preemphasis circuit, the input of voice modulation coding circuit respectively; Filter circuit adopts the filtering of LC formula, and wherein inductance L adopts week in the colour TV line frequency 15.625KHz filtering, the very little above high-frequency interferencing signal of 15KHz of the sense of hearing in the filtering audio frequency; Preemphasis circuit adopts single-stage RC formula preemphasis, forms preemphasis network by resistance, electric capacity; The electronic component that the audio frequency simulation compressor circuit amplifies chip and their peripheries by audio frequency simulation compression/extension chip and computing is formed by connecting.
The voice modulation coding circuit is formed by connecting by audio modulating circuit and audio amplifier circuit, the input of audio modulating circuit, output connect the output of audio frequency filtering shaping circuit, the input of audio amplifier circuit respectively, and the output of audio amplifier circuit connects the input of vibration and phase-locked loop circuit; Audio modulating circuit is formed by connecting by dual-channel audio hybrid modulation chip and peripheral resistor network thereof, and audio amplifier circuit amplifies chip by computing and peripheral resistance, electric capacity is formed by connecting.
Vibration and phase-locked loop circuit are made of oscillating circuit, phase-locked loop circuit and cpu control circuit, the output of oscillating circuit connects the input of phase-locked loop circuit, the output of phase-locked loop circuit connects the input of high frequency amplification and coupling output circuit, the control input end of phase-locked loop circuit connects the output of cpu control circuit, the frequency of cpu control circuit control phase-locked loop circuit.
High frequency amplifies and the coupling output circuit is formed by connecting by high-frequency amplifier circuit, low-pass filter circuit and coupling output circuit, the output, output that the input of high-frequency amplifier circuit connects phase-locked loop circuit connects the input of coupling output circuit by low-pass filter circuit, and the output of coupling output circuit is coupled to high-frequency signal on the alternating current wires of 220V.
High-frequency coupling and input circuit are formed by connecting by high-frequency coupler, input circuit, high-frequency coupler by high frequency transformer be formed by connecting with electric capacity, its input receives the high-frequency signal of high-voltage power-line, the input that output is connected input circuit, input circuit is formed by connecting by protective circuit, filter circuit and amplifying circuit, and its output connects the input of local oscillation circuit; Local oscillation circuit is formed by connecting by triode Q1, transformer T1, switch S 2, resistance R 2, R3, R4, crystal oscillator X5, X6, X7 and capacitor C 14, and its output connects the input of the integrated receiving circuit of FM; The integrated receiving circuit of FM receives tuning reception IC by AM/FM and peripheral circuit is formed by connecting, and its output connects the input of audio signal processing circuit; Audio signal processing circuit is formed by connecting by filter circuit amplification, expanded circuit and tone control circuit, and its output connects the input of power amplifier; Power amplifier is formed by connecting by audio frequency power amplifier chip and peripheral resistance thereof, electric capacity, and its output connects the input of three-dimensional speaker group; Squelch circuit is formed by connecting by singlechip chip and peripheral triode thereof, resistance, electric capacity etc., and its output connects the noise control end of power amplifier; The output of power circuit connects the power input of aforementioned each circuit.
The present invention has following outstanding advantage:
1, the stereo audio signal shaping is modulated on the high frequency carrier, again high frequency carrier being coupled in power line sends, the transmitter and receiver major part is made of integrated chip, therefore simple, the stable performance of circuit structure, the FM signal that transmitter sends is stable and what send is stereo audio signal, receiver not only can be play monaural broadcast singal, and can play stereophonic broadcasting, the stereo broadcast terminal of formation.
2, the present invention by existing power line transmission stereo audio signal, need not be special transmission lines, frequency band does not take up room, do not disturb spatial microwave to transmit, can realize Hi-Fi stereo transmission, have the easy easy realization of circuit, simple to operate, can select characteristics such as transmission frequency.
The drawing explanation
Fig. 1 is the structured flowchart of the transmitter of the embodiment of the invention 1.
Fig. 2 is the audio frequency input circuit schematic diagram of the transmitter of the embodiment of the invention 1.
Fig. 3 is audio frequency filtering, shaping and the modulation circuit schematic diagram of the transmitter of the embodiment of the invention 1.
Fig. 4 is vibration, the phase-locked loop circuit schematic diagram of the transmitter of the embodiment of the invention 1.
Fig. 5 is the vibration of transmitter of the embodiment of the invention 1 and the cpu control circuit schematic diagram of phase-locked loop circuit.
Fig. 6 is the high-frequency amplifier circuit schematic diagram of the transmitter of the embodiment of the invention 1.
Fig. 7 is the coupling output power supply circuit schematic diagram of the transmitter of the embodiment of the invention 1.
Fig. 8 is the structured flowchart of the receiver of the embodiment of the invention 1.
Fig. 9 is the electrical schematic diagram of the receiver of the embodiment of the invention 1.
Figure 10 is the high-frequency coupling and the input circuit schematic diagram of the receiver of the embodiment of the invention 1.
Figure 11 is the audio signal processing circuit schematic diagram of the receiver of the embodiment of the invention 1.
Preferred embodiment
Fig. 1 to Figure 11 constitutes embodiments of the invention 1.As can be seen from Figure 1, the transmitter of present embodiment is formed by connecting by audio frequency input circuit 1-1, audio frequency filtering shaping circuit 1-2, voice modulation coding circuit 1-3, vibration and phase-locked loop circuit 1-4, high frequency amplification and coupling output circuit 1-5 and power circuit 1-6.Receiver is formed by connecting by high-frequency coupling and input circuit 2-1, the integrated receiving circuit 2-3 of local oscillation circuit 2-2, FM, audio signal processing circuit 2-4, power amplifier 2-5, squelch circuit 2-6, stereo loudspeaker group 2-7 and power circuit 2-8.As can be seen from Figure 8, the transmitter of present embodiment is formed by connecting by high-frequency coupling and input circuit 2-1, the integrated receiving circuit 2-3 of local oscillation circuit 2-2, FM, audio signal processing circuit 2-4, power amplifier 2-5, squelch circuit 2-6, stereo loudspeaker group 2-7 and power circuit 2-8.
As can be seen from Figure 2, the audio frequency input circuit mainly is the stereo audio signal of audio interface input to be made amplitude limit amplify, and promptly imports audio amplitude hour, and multiplication factor is bigger; When input range is excessive, reduce multiplication factor relatively, and keep undistorted.The importation is mainly amplified by amplitude limit and automatic gain control amplification two parts are formed.
Three audio interface J1, J2, J3 of transmitter are connected with external sound source respectively, are divided into low level input and high level and import two classes, select input by switch S 1.The audio frequency signal amplitude of low level input input is usually less than 1V (effective value), with resistance R7, R8, R9, R10 directly be coupled import just passable; And the audio frequency signal amplitude of high level input input is very big usually, and 1V～18V (effective value) is for avoiding excessive other components and parts of current/voltage impact failure, so need to import through the amplitude limiting amplifier circuit of being made up of the TLO72 operational amplifier again.The gain of this amplifying circuit is G=R5/R3.
Automatic gain control (ALC) amplifying circuit mainly is made up of KA22241 chip and peripheral circuit thereof.Audio signal is input to later KA22241 again through the resistor network decay that R17, R18, R19, R20, R21, R22 form earlier, KA22241 is that the dual track prime of the band automatic gain control of Samsung semiconductor company production is amplified chip, audio signal is imported from the 2nd, the 8th pin, is exported by the 3rd, the 7th pin after the chip internal alc circuit amplifies.1st, the 9th pin is the negative feedback input, and the 5th pin is the ALC control end, and the 6th pin is a power end.
Automatic gain control circuit can also adopt other chip to realize, as LS22241 and the KA2220 of Samsung or the BA3308 of ROHM company etc. of LIGHTNING company.
As can be seen from Figure 3, the audio frequency filtering shaping circuit is the adjustment member of audio signal waveform, and this part has important effect for parameters such as the signal to noise ratio of complete machine, the distortion factors.Filtering shaping circuit is divided into filtering, preemphasis and audio frequency simulation and compresses three parts.
The audio signal of alc circuit output is input to filter circuit through R28, R29, R31, R32 resistance net dividing potential drop.The filtering partial circuit adopts LC filtering, and wherein inductance L 3, L4 adopt week in the colour TV line frequency 15.625KHz filtering, the high-frequency interferencing signal that the 15KHz that auditory induction is very little in the filtering audio frequency is above.
What preemphasis partly adopted is that single-stage RC increases the weight of, and C21, C22, R35, R36 form preemphasis network, to the audio signal 3dB weighting more than the 2KHz, helps the fidelity of noise reduction and intermediate-freuqncy signal.Be coupled to compandor by R23, R24 electrolysis after the audio signal preemphasis.
What the analog signal compressor circuit adopted is the audio frequency simulation compression/extension chip SA572N of philips semiconductor company and the NJM4560 amplifier of NJRC company.The function of audio compression circuit is the compression to small-signal, is used the effect of eliminating noise that reaches with expanded circuit in the receiver.Be similar to Doby B, the C compression noise reduction technology principle of Doby company.
The analog signal compression chip can also maybe can omit this part circuit with the isobaric expansion of SA571, the SA575 IC of philips semiconductor company.
As can be seen from Figure 4, the voice modulation partial circuit is fed to audio modulating circuit from the audio signal of compandor SA572 output.Modulation circuit is made up of voice modulation and amplification two parts, sends into the amplifying circuit amplification that TL072 forms referring to accompanying drawing 4 stereo audio signals later on through the IC hybrid modulation.
Be imported into the BA1404 chip after audio signal process R49, R50, Ra, the Rb resistor network dividing potential drop.BA1404 is the dual-channel audio hybrid modulation chip that ROHM company produces.Audio signal is imported by the 1st, the 18th pin, and signal is sent into the MPX balanced modulator after left and right sides signal channels amplifier amplifies, and the difference signal S of generation is modulated on the 38K subcarrier that is produced by crystal oscillator, exports from the 14th pin.The 13rd pin output 19KHz pilot signal.5th, the external 38K crystal oscillator of the 6th pin, the 16th, the 17th pin is the adjustment of left and right acoustic channels balance, the 15th, the 3rd pin connects power supply and ground respectively.
The modulating wave of BA1404 output and pilot signal are coupled to the two-stage amplification that amplifier TL072 forms through electrolysis C58 after C55, C56, R54, R54 mix.The first order is amplified Ga=R57/R56=5, and second level amplification is adjusted output amplitude by the size of VR2 Control and Feedback amount, and signal is through C62 coupling output.
From Fig. 4, Fig. 5 as can be known, vibration and phase-locked loop partial circuit major function are that the modulation and the mixed signal of pilot tone are loaded on the high frequency carrier of oscillating circuit generation, and use the stabilized frequency.Comprise that Voltage-Controlled oscillation circuit, phase-locked loop circuit, CPU control three parts.
Voltage-Controlled oscillation circuit (VCO) usefulness be the vibrations of active three ends, adopt the DC level control variable capacitance diode of CPU control phase-locked loop output to come gear shift and stabilized frequency.The size of capacitor C a, Cb and inductance L has determined frequency of oscillation.
The phase-locked loop circuit of CPU control is mainly used in frequency stabilization, that phase-locked loop adopts is the PLL phase-locked loop MC145170 of motorola company of Motorola, frequency of oscillation from the introducing of MC145170 the 4th pin, deliver to CPU by data wire, CPU relatively produces a control signal with data and set point, control phase-locked loop MC145170 and the 14th, the 15th pin output pulse width, 14th, the pulse of the 15th pin output becomes DC level through the discharge circuit Integral Transformation, is input to the variable capacitance diode two ends of Voltage-Controlled oscillation circuit (VC0) after mixing with the signal of C62 output again.
As can be seen from Figure 5, cpu circuit mainly is to select and control frequency, and that CPU adopts is the 8-bit microprocessor EM78P156E of EMC Inc..CPU selects the frequency of setting by the conducting state of the toggle switch that detection is attached thereto, and controls phase-locked loop and come stabilized frequency.CPU can use the general-purpose microprocessor chips of other companies.
As can be seen from Figure 6, the high frequency carrier that has loaded modulating wave is input to high-frequency amplifier circuit and is exaggerated, and through the low pass filter of a LC network, is coupled on the power line by output winding at last again.High-frequency amplifier circuit adopts two-stage to amplify.The first order is that two-tube SRPP amplifies, and multiplication factor is approximately 50.The second level is that complementary push-pull output is amplified, and adopts 2N3904,2N3906, and multiplication factor is about 10.The high-frequency signal that amplifies is by C87 coupling output.High-frequency amplifier circuit can also be put the chip realization with other special-purpose height.
Form one three rank low filter, the harmonic component of filtering high-frequency signal by L7, L8, L9, L10, L11, C88, C89, R95.Be coupled on the 220V power line by the coil of 3:1 at last through the later high frequency carrier of amplification filtering, launch by power line.
From Fig. 8 to Figure 11 as can be known, receiving circuit is made up of high-frequency coupler, input circuit, frequency mixer, local oscillator intermediate frequency amplifier, amplitude limiter, frequency discriminator, stereo synchronizing separator circuit, expander power amplifier etc.Its workpiece principle is: from power line transmission frequency modulation electromagnetic wave through coupler, input circuit is delivered to high-frequency amplifier and is amplified, carry out mixing at frequency mixer and local oscillation signal, obtain the 10.7KHz intermediate-freuqncy signal, intermediate-freuqncy signal obtains the stereo mix signal through filtering, frequency discrimination, mixed signal is delivered to the stereo decoding circuit, carry out separated in synchronization, the three-dimensional signal of two sound channels about output has, the modulation signal that restores is through after the processed, stereophonic reproduction is carried out in the work of promotion loudspeaker.This shows, power line FM reception audio amplifier circuit and stereo ceiver circuit are roughly the same, different is: receive the mode difference of high-frequency signal, power line FM reception audio amplifier is coupled signal from the power line directly, and broadcast receiver then is from aerial induction of high frequency signal by antenna.Because the signal of stereo power line transmission system adopts the power line transmission mode, so efficiency of transmission height, antijamming capability are strong, and the width of cloth penetrates little, environmental protection, and this is that other wireless transmission method is incomparable.
The main effect of high-frequency coupler and input circuit is: (1) coupling, received signal from the power line.(2) isolate, be with forceful electric power on the power line, power line and receiving circuit are isolated fully on electric with high-frequency coupling.(3) impedance conversion and filtering.
High-frequency coupler is made up of T402, T403, C400, and T402, T403 are identical, is the high frequency transformer by the coiling of diplopore iron gas magnetic core, and first umber of turn is 1:3 or 2:2.Generally speaking, use a coupler promptly to meet design requirement, in order to improve sensitivity, adopt two couplers, to increase input impedance.The effect of C400 is: coupling, promptly logical high frequency resistance low frequency.Input circuit mainly is made up of protective circuit, filter circuit, amplifying circuit.As shown in Figure 9; Q6, Q7, Q8 and peripheral cell have been formed protective circuit; Q6, Q8 adopt the form of reversal connection in parallel; its effect is equivalent to the diode of two reverse parallel connections; be used for absorbing high-voltage pulse; Q7 is an emitter follower, makes the impedance between frequency conversion coupler and the filter realize coupling.
Filter circuit is made up of L1, L2, L3, C44, C45, C46, L1, C44 and L2, C45 constitute two LC series resonant circuits respectively, and L2, C45 constitute a parallel circuits, and the resonance frequency of three lc circuits all is 27MHz, the 3dB band of filter is 6MHz, and it inserts loss is 6dB.
Q2, R2, T2, C103, R5 form a 27MHz high-frequency amplifier, and to improve receiving sensitivity, Amplifier Gain is 10dB, and Q2 adopts 2SC1674Y or 2SK1674Y, and its characteristic frequency is fT=600MHz.T2 adopts the tap access way, can improve the Q value of circuit like this.
Local oscillation circuit is made up of Q1, T1, S2, R2, X5, X6, X7, R3, C14, R4, this is a crystal resonant circuit, S2 is one three and selects one switch, the resonance frequency of crystal X3～5 is respectively 36.94,37.44,37.94MHz, select by S2, can produce above three kinds of different local frequencies.Q3 is a buffer, make 21 pin of local oscillation circuit and TA8122 realize impedance matching, the resonance amplitude of local oscillation circuit be-40dBm about, penetrate in order to reduce the width of cloth, with shielding to cover local oscillation circuit is shielded.
The integrated receiving circuit U9-TA8122AN/AF-TA8123AF:TA8122AN/AF of FM is that the AM/FM that the design of TOSHIBA company is produced receives tuning reception IC, is mainly used in pocket radio set and wireless headphone system.Chip internal is integrated input circuit, high-frequency amplifier circuit, variation parallel operation, frequency discriminator, stereo decoding circuit.
TA8122, the main electric index of 23AN/AF chip:
Current sinking: (FM pattern) 18.5mA
Audio frequency output: 80mV
Signal to noise ratio: 70dB
The distortion factor: 0.4%
Separating degree: 42dB
Receiving sensitivity: 3uV
TA8122,23AN/AF have two kinds of packing forms, and wherein TA8122,23AN are the dual-in-line form.Title is SSOP24-P-300-1.78; TA8122,23AF are the surface mount form, and encapsulation number is SSOP24-P-300-1.00, two kinds of form differences, and function is in full accord.
TA8122,23AN/AF peripheral circuit: element Y4, X3 are respectively ceramic filter and ceramic discriminator, adopt three end ceramic filters, put peripheral cell in making and significantly reduce.Wherein X4 is a ceramic discriminator, and frequency is 456KHz, and it and IC internal circuit are formed phase-locked loop (PLL), and stereo mixed signal is decoded.C242, C243, C244, C250 are filter capacitor.
Signal flow among the IC is: carrier signal is imported by the 1st pin, can obtain required stereo audio signal at the 13rd, 14 pin, the conversion of all signals, amplification and decoding are all finished in a slice IC, and therefore, TA8122,23AN/AF are the core devices of receiving circuit.The IC that can replace TA8122,23AN/AF chip in the circuit has: the TA2111N of TOSHIBA company, encapsulation number for SDIP24-P-300-0.05A, and the CXA1538M of Sony Corporation, encapsulation number is 30PIN, SDIP.
The principle of filtering signal treatment circuit: as we know from the figure, the stereophonic signal that obtains from U9 the 13rd, 14 pin also need be handled accordingly and just can deliver to power amplifier and realize stereophonic reproduction.Audio signal processing circuit comprises filter amplification circuit, expanded circuit, tone control circuit.
Filter amplification circuit: filter amplification circuit is made up of Q203, Q206, L8, L9, C261, C262, U30, and (R, L) two sound channels symmetry fully about on the circuit is so it is just passable only to analyze R (right side) sound channel partial circuit.
Filter circuit: in the R sound channel, filter circuit is made up of C244, C245, C248, R201, Q203, R203, C207, C261, L8, C216, and C245, C261 are filter capacitor.,, with the radio-frequency component in the filtering audio signal.C216 also is a critical elements in the deaccentuator, and Q203 is connected into the buffer form and improves filter effect.C261, L8 are the LC parallel circuits, are used for filtering 19KHz pilot signal, and C261, C216 use terylen electric capacity, and its error is 5%, so just can obtain filter effect preferably.
Amplifying circuit: U3-4 and resistance R 32, R40, R35 constitute a typical inverting amplifier, and R32 is a negative feedback resistor, change the value of R32, just can change the multiplication factor of amplifier.
S1 is the same with S2, is a three elections switch, is used for selecting sound channel, have three kinds available, i.e. L channel, R channel, monophony.
Expanded circuit: for the dynamic range of expanding modulation, demodulation, playback audio signal, reduce caused distortion and noise in the transmission course, in power line stereo transmission system, we have used companding technology, in transmitter, the modulation stereophonic signal is compressed, correspondingly in receiver, need exchange the audio signal of separating out and carry out extension process.
Expanded circuit is made up of U3-2, U3-3, U8 and peripheral cell, U3-3 is connected into buffer, be used for impedance matching, U3-2 and R23, R28, C35 constitute an inverting amplifier, U8 the 6th pin provides biasing to the U3-2 amplifier, U8 adopts the SA572 of PHILIPS company, and SA572 is the wide dynamic range companding IC of a dual track.At receiver, only make a passage, when the expander use, the dynamic range of expander reaches 110dB, can be used to replace U9, and the IC of SA572 also has: SA570/571, SA575.
Tone control circuit: U1A (TL072 IC) is connected into differential input form, and to reduce common mode disturbances, R9 is the 47K variable potentiometer, is used to regulate volume, i.e. VOLUME.Tone control circuit is made up of element R12, R14, R19, R20, SW1, C3, C4, R15, R16, R18, R13, C2, C5, this is a RC attenuation type tone circuit, high pitch is regulated and is controlled by R16, when the Rp of R16 (tap) puts when A holds, treble boost, when shifting to the B end, the high pitch decay.SW1 is the bass switch, beats when C holds when switch, is in the high pitch position, when switch when D holds, be in the bass position.Tone control circuit is used for improving tonequality, because audio signal is through decay to some extent behind the tone control circuit, therefore, the back need connect amplifying circuit usually, and is enough big with the amplitude that guarantees audio signal, can promote power amplifier work.U1B and peripheral cell R21, R22, R23 are exactly such circuit, and circuit theory as previously mentioned.
Power amplifier is formed by connecting by U4LM1875T and peripheral cell R401, C412, R402, R403, R405, R404, R406, C411, U4 is the audio frequency power amplifier chip IC that a power is 20W, LM1875 is the product of National Semiconductor, and packing forms is TO-220.In an embodiment, the LM1875 dual power supply, maximum undistorted output voltage can reach 10Vrms.
Squelch circuit also is the MUTE circuit, is formed by connecting by U6 and Q10, Q4, Q5, Q6 and peripheral cell, and U6 adopts singlechip chip IC EM78P153E or other general little process chip.By detecting the 11 pin level of U9, TA8122, to handle through software delay, control Q6 switch reaches the purpose of MUTE.Q6 adopts MMBF439LT1 field effect transistor serial connection form, the audio noise when suppressing the disturbing pulse of circuit start moment and no signal, and the noise elimination effect is better.And the attenuation of noise〉60dB.
Claims (7)
1. power line transmission sound box system, it is characterized in that: transmitter is by audio frequency input circuit (1-1), audio frequency filtering shaping circuit (1-2), voice modulation coding circuit (1-3), vibration and phase-locked loop circuit (1-4), high frequency amplification and coupling output circuit (1-5) and power circuit (1-6) are formed by connecting, the input of audio frequency input circuit (1-1), output connects the source of sound output respectively, the input of audio frequency filtering shaping circuit (1-2), the input of voice modulation coding circuit (1-3), output connects the output of audio frequency filtering shaping circuit (1-2) respectively, the input of vibration and phase-locked loop circuit (1-4), the input of high frequency amplification and coupling output circuit (1-5), output connects the output of vibration and phase-locked loop circuit (1-4) respectively, power line, the output of power circuit (1-6) connects the power input of each circuit; Audio frequency input circuit (1-1) is formed by connecting by audio interface and automatic gain control circuit, audio interface is connected with external sound source, import by low level, high level is imported two groups of input interfaces and is constituted, its output connects two inputs of selector switch S, the output of switch S connects the input of automatic gain control circuit, the output of high level interface connects the input of selector switch S by amplitude limiter circuit, automatic gain control circuit mainly amplifies chip by the dual track prime of band automatic gain control and the peripheral electron element is formed by connecting, and its output connects the input of audio frequency filtering shaping circuit (1-2).
2. power line transmission sound box system as claimed in claim 1, it is characterized in that: receiver is by high-frequency coupling and input circuit (2-1), local oscillation circuit (2-2), the integrated receiving circuit of FM (2-3), audio signal processing circuit (2-4), power amplifier (2-5), squelch circuit (2-6), stereo loudspeaker group (2-7) and power circuit (2-8) are formed by connecting, the input of high-frequency coupling and input circuit (2-1) receives high-frequency signal from power line, output connects the input of the integrated receiving circuit of FM (2-3), the input of audio signal processing circuit (2-4), output connects the output of the integrated receiving circuit of FM (2-3) respectively, the input of power amplifier (2-5), the input of squelch circuit (2-6), output connects the output of power amplifier (2-5) respectively, the input of stereo loudspeaker group (2-7), the output of power circuit (2-8) connects the power input of each circuit; High-frequency coupling and input circuit (2-1) are formed by connecting by high-frequency coupler, input circuit; high-frequency coupler by high frequency transformer be formed by connecting with electric capacity, its input receives the high-frequency signal of high-voltage power-line, the input that output is connected input circuit; input circuit is formed by connecting by protective circuit, filter circuit and amplifying circuit, and its output connects the input of local oscillation circuit (2-2).
3. power line transmission sound box system according to claim 1, it is characterized in that: audio frequency filtering shaping circuit (1-2) is made of filter circuit, preemphasis circuit and audio frequency simulation compressor circuit, the input of filter circuit connects the output of audio frequency input circuit (1-1), the input that output connects preemphasis circuit, and the input of audio frequency simulation compressor circuit, output connect the output of preemphasis circuit, the input of voice modulation coding circuit (1-3) respectively; Filter circuit adopts the filtering of LC formula, and wherein inductance L adopts week in the colour TV audio frequency 15.625KHz filtering, the very little above high-frequency interferencing signal of 15KHz of the sense of hearing in the filtering audio frequency; Preemphasis circuit adopts single-stage RC formula preemphasis, forms preemphasis network by resistance, electric capacity; The electronic component that the audio frequency simulation compressor circuit amplifies chip and their peripheries by audio frequency simulation compression/extension chip and computing is formed by connecting.
4. power line transmission sound box system according to claim 1, it is characterized in that: voice modulation coding circuit (1-3) is formed by connecting by audio modulating circuit and audio amplifier circuit, the input of audio modulating circuit, output connect the output of audio frequency filtering shaping circuit (1-2), the input of audio amplifier circuit respectively, and the output of audio amplifier circuit connects the input of vibration and phase-locked loop circuit (1-4); Audio modulating circuit is formed by connecting by dual-channel audio hybrid modulation chip and peripheral resistor network thereof, and audio amplifier circuit amplifies chip by computing and peripheral resistance, electric capacity is formed by connecting.
5. power line transmission sound box system according to claim 1, it is characterized in that: vibration and phase-locked loop circuit (1-4) are made of oscillating circuit, phase-locked loop circuit and cpu control circuit, the output of oscillating circuit connects the input of phase-locked loop circuit, the output of phase-locked loop circuit connects the input of high frequency amplification and coupling output circuit (1-5), the control input end of phase-locked loop circuit connects the output of cpu control circuit, the frequency of cpu control circuit control phase-locked loop circuit.
6. power line transmission sound box system according to claim 1, it is characterized in that: high frequency amplifies and coupling output circuit (1-5) is formed by connecting by high-frequency amplifier circuit, low-pass filter circuit and coupling output circuit, the output, output that the input of high-frequency amplifier circuit connects phase-locked loop circuit connects the input of coupling output circuit by low-pass filter circuit, and the output of coupling output circuit is coupled to high-frequency signal on the alternating current wires of 220V.
7. power line transmission sound box system according to claim 2, it is characterized in that: local oscillation circuit (2-2) is formed by connecting by triode Q1, transformer T1, switch S 2, resistance R 2, R3, R4, crystal oscillator X5, X6, X7 and capacitor C 14, and its output connects the input of the integrated receiving circuit of FM (2-3); The integrated receiving circuit of FM (2-3) receives tuning reception IC by AM/FM and peripheral circuit is formed by connecting, and its output connects the input of audio signal processing circuit (2-4); Audio signal processing circuit (2-4) is formed by connecting by filter circuit amplification, expanded circuit and tone control circuit, and its output connects the input of power amplifier (2-5); Power amplifier (2-5) is formed by connecting by audio frequency power amplifier chip and peripheral resistance thereof, electric capacity, and its output connects the input of three-dimensional speaker group (2-7); Squelch circuit (2-6) is formed by connecting by singlechip chip and peripheral triode thereof, resistance, electric capacity etc., and its output connects the noise control end of power amplifier; The output of power circuit (2-8) connects the power input of aforementioned each circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021218242A CN100490345C (en) | 2002-06-06 | 2002-06-06 | Power line transmission sound box system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021218242A CN100490345C (en) | 2002-06-06 | 2002-06-06 | Power line transmission sound box system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1464641A CN1464641A (en) | 2003-12-31 |
| CN100490345C true CN100490345C (en) | 2009-05-20 |
Family
ID=29743069
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021218242A Expired - Fee Related CN100490345C (en) | 2002-06-06 | 2002-06-06 | Power line transmission sound box system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100490345C (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101621312B (en) * | 2009-07-29 | 2012-12-26 | 昆明天龙经纬电子科技有限公司 | Power line carrier communication chip established by utilizing singlechip |
| TWI440368B (en) * | 2011-01-26 | 2014-06-01 | Aten Int Co Ltd | Signal extending system, and transmitter and receiver thereof |
| CN103916766A (en) * | 2012-12-31 | 2014-07-09 | 广州励丰文化科技股份有限公司 | High-quality active integrated loudspeaker with quite low background noise |
| CN107390183B (en) * | 2017-08-22 | 2023-05-12 | 无锡晶磊电子有限公司 | Narrow pulse width high frequency modulator |
| CN109951212A (en) * | 2019-02-27 | 2019-06-28 | 重庆邮电大学 | A kind of remote audio line data communication package based on PRIME standard |
| TWI743800B (en) * | 2020-05-22 | 2021-10-21 | 瑞昱半導體股份有限公司 | Circuitry and method for detecting audio standard of sound intermediate frequency signal |
-
2002
- 2002-06-06 CN CNB021218242A patent/CN100490345C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1464641A (en) | 2003-12-31 |
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Granted publication date: 20090520 Termination date: 20110606 |