CN1056026A - Noise-reducing receiving circuit - Google Patents
Noise-reducing receiving circuit Download PDFInfo
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- CN1056026A CN1056026A CN 90102382 CN90102382A CN1056026A CN 1056026 A CN1056026 A CN 1056026A CN 90102382 CN90102382 CN 90102382 CN 90102382 A CN90102382 A CN 90102382A CN 1056026 A CN1056026 A CN 1056026A
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Abstract
The present invention relates to a kind of noise-reducing receiving circuit, it is by frequency changer circuit, oscillating circuit, mixting circuit and frequency selection circuit, difference frequency frequency selection circuit, radio station carrier wave select circuit, the selection of signal intermediate frequency noise carrier and amplifying circuit, signal intermediate frequency wave circuit, noise carrier detecting circuit, merging circuit etc. to form frequently.Owing to set up in the amplifying circuit detection before a kind of and the signal carrier different frequency and the weak high-frequency alternating current of band signal not, allow each element produces in the receiving circuit noise voltage when signal carrier is gone in modulation, also modulate the high-frequency alternating current of going into to set up, and the reverse detection of employing in detecting circuit, obtain another noise voltage identical with noise voltage intensity in the signal demodulator but that phase place is opposite, realize anti-phase payment.
Description
The present invention relates to a kind of receiving circuit, particularly a kind of noise-reducing receiving circuit.
In the prior art, the way that radio receiver circuit reduces noise has: high frequency attenuation method, dynamic noise suppress method, static noise suppresses method, Bel's noise reduction system, Dolby system etc.These technology all are suitably to reduce noise in receiving circuit, and do not obtain eliminating more completely.
The objective of the invention is to avoid above-mentioned the deficiencies in the prior art part and a kind of not weak high-frequency alternating current of band signal of having set up in circuit is provided, and suitable voltage payment principle, can eliminate the de-noising circuit of noise more up hill and dale.
Purpose of the present invention can reach by following measure: the present invention includes frequency changer circuit, the radio station carrier wave is selected circuit, the signal intermediate frequency detecting circuit, it is characterized in that: go back two oscillating circuits in ground, mixting circuit, with the frequency frequency selection circuit, the difference frequency frequency selection circuit, signal intermediate frequency, noise carrier is selected and amplifying circuit, the noise carrier detecting circuit, be merged circuit, the high frequency voltage that two oscillating circuits produce two kinds of different frequencies respectively is input to mixting circuit, mixting circuit one tunnel output is through selecting with the frequency frequency selection circuit and entering frequency changer circuit after (local oscillation frequency) frequently, another road output also enters frequency changer circuit after the difference frequency frequency selection circuit is selected difference frequency (noise carrier), the radio station carrier wave selects the output of circuit also to enter frequency changer circuit in addition, signal after the frequency changer circuit frequency conversion passes through signal intermediate frequency, noise carrier is selected and back one tunnel entering signal intermediate frequency detecting circuit is amplified in the amplifying circuit frequency-selecting, the signal that the signal intermediate frequency detecting circuit detects is sent into and is merged circuit, another road enters the noise carrier detecting circuit, the noise voltage that the noise carrier detecting circuit detects enters and is merged circuit, be merged the output radio signals with the noise contribution in the signal.2 ends of transformer B2 connect the emitter-base bandgap grading of BG4 in the mixting circuit in the oscillating circuit by capacitor C 20,2 ends of transformer B1 are by capacitor C 7 in the oscillating circuit, potentiometer W1 connects the base stage of BG4, the collector electrode of BG4 connects 1 end of B4 in the difference frequency frequency selection circuit, and by 1 of B4,2 ends of B3 in 2 terminations and the frequency frequency selection circuit, 4 ends of B3 are by 5 of B6, the base stage of BG6 in the 4 termination frequency changer circuits, 6 ends of B3 are by 7 of B6, the base stage of BG5 in the 6 termination frequency changer circuits, 4 of B4,6 termination potentiometer W2, the mid point of W2 connects 2 ends of B6, BG5, the collector electrode of BG6 connects signal intermediate frequency respectively, in the noise carrier selective frequency amplifier circuit 1 of B7,3 ends, 4 ends of B7 and 3 ends of B8 join, 2 ends of B8 and 3 ends of B9 join, 4 ends of B8 are by 5 of B9, the base stage of 4 termination BG8,7 of the logical B9 of 7 ends of BG8, the base stage of 6 termination BG7, BG9, the collector electrode of BG10 meets 4 of B12 respectively, 2 ends, 3 ends of the 3 termination B13 of B12, the positive pole of D2 in the 5 termination noise carrier detecting circuits of B13, the negative pole of D1 in the 6 termination signal intermediate frequency detecting circuits of B12.
This circuit is a utilization voltage payment principle, set up a kind of and signal carrier different frequency and the weak high-frequency alternating current of band signal not in the amplifying circuit before detection, allow noise voltage that each element of receiving circuit produces when signal carrier is gone in modulation, also modulation goes into to set up high-frequency alternating current (this high frequency is called " noise carrier ").In detecting circuit, adopt reverse detection (for the detection of signal carrier), obtain with signal carrier in another opposite noise voltage of noise voltage intensity equal phase, be merged then, realize anti-phase payment, export purer radio signals, thereby the noise voltage before the detection is eliminated.
Fig. 1 is a functional-block diagram of the present invention;
Fig. 2 is an electrical schematic diagram of the present invention.
The present invention is described in further detail below in conjunction with accompanying drawing (embodiment):
With reference to Fig. 1, the present invention is by oscillating circuit 1,2, mixting circuit 3 and rate frequency selection circuit 4, difference frequency frequency selection circuit 5, frequency changer circuit 6, radio station carrier wave are selected circuit 7, signal intermediate frequency, noise carrier selects again and again and amplifying circuit 8, signal intermediate frequency detecting circuit 9, noise carrier detecting circuit 10, be merged circuit 11 and form.
This circuit must solve several problems: 1. will realize comprehensively offseting of noise voltage, must make signal carrier and noise carrier comprise equal noise contribution; 2. the noise carrier of input amplifying circuit must very weak (similar with the radio station strength of carrier); 3. must take the separating power of special measure raising to signal carrier and noise carrier, because it is all more intense to arrive two carrier waves of afterbody selecting tuning circuit, general system of selection is difficult to two carrier separation clear, scurry into as signal carrier that the noise circuit goes detection, the signal after then being merged is just because most of payment the and very weak.
Narrate the technical finesse of this three aspect below respectively:
1. the frequency of oscillation of two oscillating circuit generations is imported mixting circuits, by choosing mixing respectively with frequency frequency selection circuit, difference frequency frequency selection circuit with frequently and difference frequency, the purpose of mixing is that the frequency of oscillation of two each self-contained different noise contributions is transformed into the new frequency that comprises equal noise contribution.The mixing of carrying out for this reason is called " mix and make an uproar ".Mix make an uproar and and frequently (F1+F2) make " local oscillation frequency " of superheterodyne reception, and send into frequency changer circuit by choosing with the frequency frequency selection circuit, the radio station carrier wave selects the radio station carrier wave of circuit also to send into frequency changer circuit, conversion goes out signal intermediate frequency.Like this,, just in frequency conversion, brought signal intermediate frequency into, but because the radio station carrier wave is very weak, the noise contribution of bringing into weakens greatly by the mixed unified noise contribution of noise cancellation circuit.Mixing and difference frequency, choose by the difference frequency frequency selection circuit, make noise carrier, also import frequency changer circuit, noise carrier is also with entering frequency changer circuit (noise carrier only comprises noise, not band signal owing to not being to get with radio station carrier wave frequency conversion) by the mixed unified noise contribution of noise cancellation circuit.For making this noise contribution and the noise contribution equivalent of bringing signal intermediate frequency into, the noise carrier of input frequency changer circuit must be impaired to suitable weak degrees by the potentiometer adjustment, and the two carrier noise content of bringing frequency changer circuit into are equated.
2. the noise carrier of realizing input amplifying circuit must very faint measure.Experimental results show that, above-mentioned F1 and F2 frequency of oscillation only depend on line influence to the input of amplifying circuit converter stage excess just, the noise carrier that makes mixing and get is more much better than than the radio station carrier wave that receives, and, can take " balanced oscillator circuit " in order to reduce the input voluntarily of this line influence.
3. improve the separating power to signal carrier and noise carrier, can adopt two-tube amplification to circuit at different levels, each Guan Jun serves as the amplification of two carrier waves.In input circuits at different levels, respectively signal carrier and noise carrier are taked different input forms anti-phase and homophase, in the selecting tuning circuit of output, correspondingly take the system of selection of paraphase and not paraphase, like this, the carrier wave that the selecting tuning circuit is chosen itself is the two-way addition, is that two-way subtracts each other to another carrier wave, this system of selection is called the plus-minus partition method, and this method can sort out two carrier waves very up hill and dale.
With reference to Fig. 2, BG1, element Compositional balance oscillating circuits such as BG2, central BG1, B1, C1～C5 forms common oscillating circuit, vibration circle B1 increases a tap than common vibration circle, many by 3 to 4 small coil, this small coil is opposite with the direction of 2 to 3 small coils, oscillating current is to the input of BG2 base stage and the input inversion of BG1 base stage, therefore BG1 is opposite with the variation of BG2 collector current, as long as the emitter resistance R1=R2 of two pipes, the variation of two pipe collector electric currents is payment just, the electric current that X is ordered is constant, be that electric current on the power line is constant, as long as 6 ends and the BG2 collector electrode of B1 are close, the line influence of oscillating circuit is with regard to pettiness very.Oscillating circuit is imported voluntarily and must be controlled the induction of amplifying circuit.BG3 and vibration circle B2, C9～C13 etc. form another common oscillating circuit.The frequency of balanced oscillator circuit is through C7, W1 input BG4, and the frequency of BG3 oscillating circuit is imported BG4 through C20, serves as mixing type by BG4 and mixes and to make an uproar, and W1 is that the oscillating voltage of getting suitable intensity is participated in mixing type and mixed and make an uproar.Output upper and lower side frequency (F1+F2 and F1-F2) after the mixing is promptly made noise carrier and is replaced the frequency of local oscillation to be chosen by the tuning circuit that B3, B4 form.Noise carrier (difference frequency F1-F2) is adjusted suitable intensity input B6 primary coil by W2, import BG5, BG6 respectively by two secondary coils of B6 again, and (F1+F2) chosen by the B3 tuning circuit frequently, makes " local oscillation frequency " of superheterodyne reception, input frequency-converter tube BG5, BG6.Choose the radio station carrier wave by the tuning circuit that B5, C23, C16D form, also import BG5, BG6.The potentiometer W2 that connects 2 ends of 4,6 ends of B4 and B6 transfers the noise carrier that is fit to weak degrees, by B6 input BG5, BG6.4,6 extreme directions of B4 are opposite, so through W2 input B6 is two strands of rightabout electric currents, adjust W2, central point is equated to the resistance at two ends, the input of noise carrier equals zero with regard to reverse payment, and central point to the resistance at two ends has difference, and noise carrier just has input, difference is big more, and input variable is just big more.
Two rear line heads of two secondary coils of B3 and two secondary coils of B6 are marked A, B respectively, same each end of two secondary coils of expression, and promptly in two secondary coils, the A end is identical with the sense of current of A end, the current opposite in direction that A end and B hold.From the target A of two secondary coil institutes of B6, B, because of 4 ends (A) of B6 connect the base stage of BG6, and 6 ends (B) of B6 connect the base stage of BG5, so noise carrier is anti-phase to the input of BG5, BG6; From the target A of two secondary coil institutes of B3, B, pass through the base stage of 5, the 4 termination BG6 of B6 because of 4 ends (A) of B3,6 ends of B3 are by the base stage of 7, the 6 termination BG5 of B6, (base stage of BG5, BG6 all connects the A end of two secondary coils of B3) is so B3 is selected and frequency (local oscillation frequency) is a homophase to the input of BG5, BG6.
The radio station carrier wave is to the input of BG5, BG6, is reverse because the B5 secondary coil connects two the end of a thread of BG5, BG6 emitter, so the radio station carrier wave is reverse to the input of BG5, BG6.During frequency conversion, because local oscillation frequency and radio station carrier wave are to the input of BG5, BG6 homophase not, so the signal intermediate frequency of exporting from BG5, BG6 is anti-phase.And noise carrier is because of to BG5, BG6 input inversion, and do not participate in frequency conversion, so, from the noise carrier of BG5, BG6 output also is anti-phase, to choose signal intermediate frequency and noise carrier from BG5, BG6 output, should adopt phase inverter, so primary coil of B7 is connected into paraphase, B7 is chosen for BG5, the addition of BG6 two-way, B7 secondary coil picked up signal intermediate frequency and noise carrier to signal intermediate frequency and noise carrier.Though in addition B3 be tuned in mixing and and (local oscillation frequency) frequently, but this single frequency modulation is selected circuit, can not thoroughly get rid of noise carrier, and the noise carrier of scurrying into B3 is also very strong, as allow it enter frequency changer circuit and intermediate frequency amplifier circuit, then noise carrier is strong excessively, and the noise content of two carrier waves does not just wait.But the A of two secondary coils of B3 end equal (by the B6 secondary coil) connects the base stage of BG5, BG6, through the residual difference frequency of scurrying into of B3 (being noise carrier), because of input homophase to BG5, BG6, do not participate in frequency conversion again, so from the output of BG5, BG6 also homophase, but through the B7 paraphase, the residual noise carrier of scurrying into is that two-way subtracts each other payment, obtains getting rid of more completely.
The signal intermediate frequency that the B7 secondary coil obtains and noise carrier input B8, B9 choose signal intermediate frequency by B8, and B9 chooses noise carrier.BG7, BG8 amplify signal intermediate frequency and noise carrier, but the input of noise carrier homophase is (because of 4,6 ends of B9, promptly connect the base stage of BG8, BG7 respectively) with each end A, the anti-phase input of signal intermediate frequency (4 ends (A) of B8 are by the base stage of 5, the 4 termination BG8 of B9, and 7 ends (B) are by the base stage of 7, the 6 termination BG7 of B9).In like manner, signal intermediate frequency is to BG9, BG10 input inversion, export also anti-phasely,, signal intermediate frequency is equivalent to the two ends addition through the B12 paraphase, and noise carrier is because of importing homophase to BG9, BG10, so export also homophase,, noise carrier be equivalent to two-way subtract each other through the B12 paraphase, be B12 secondary coil choosing less than noise carrier, D1 detects radio signals (comprising the noise voltage that each circuit element etc. produces).Concerning B13, BG9, BG10 are gone into mutually anti-phase because of signal intermediate frequency, so output is also anti-phase, be that two-way subtracts each other and offsets through the signal intermediate frequency of 2,3 ends of B12 and 3,4 ends input B13.And noise carrier is gone into homophase mutually to BG9, BG10, exports also homophase, is the two-way addition by 2,3 ends of B12 and the noise carrier of 4,3 ends input B13, so the B13 secondary coil is had to noise carrier, and does not have intermediate-freuqncy signal.This system of selection is called the plus-minus partition method.Noise carrier obtains noise voltage after the D2 detection.D1 detects radio signals (containing noise voltage) and is added on the W3 that is merged in the circuit by C40, the noise voltage that D2 detects is added on the W3 by C39, in being merged circuit, because of the detection direction of D1, D2 opposite, so purer radio signals is exported in the anti-phase payment of two noise voltages.Accent W3 can make the two-way noise voltage intensity that is merged equate.R13, R14 add BG7, BG8 to the mean direct voltage of signal demodulator in addition, carry out automatic gain control.R24 makes D2 add suitable forward voltage (because of R13, R14 have also added certain forward voltage to D1).The noise carrier that this circuit adopts is 200KHZ, and signal intermediate frequency is 250KHZ.Like this, according to the needs of two kinds of frequencies, when receiving the 535KHZ radio signals, frequency of oscillation F1 is 492.5KHZ, and F2 is 292.5KHZ, and when receiving 1605KHZ, F1 is 1027.5KHZ, and F2 is 827.5KHZ.
The present invention has following advantage compared to existing technology:
1. can remove more up hill and dale noise, can be applicable to radio cassette player, television set and all kinds of wireless In the receiver of electricity communication, remote control, remote measurement, can obtain purer signal.
2. reasonable in design, circuit is simple, and how many costs can not increase, but de-noising effect is better.
Claims (2)
1, a kind of noise-reducing receiving circuit, include frequency changer circuit 6, the radio station carrier wave is selected circuit 7, signal intermediate frequency detecting circuit 9, it is characterized in that: also have oscillating circuit 1,2, mixting circuit 3, with frequency frequency selection circuit 4, difference frequency frequency selection circuit 5, the signal intermediate frequency noise carrier is selected and amplifying circuit 8, noise carrier detecting circuit 10, be merged circuit 11, oscillating circuit 1,2 high frequency voltages that produce two kinds of different frequencies respectively are input to mixting circuit 3, one tunnel output of mixting circuit 3 is through selecting with frequency frequency selection circuit 4 and entering frequency changer circuit 6 after (local oscillation frequency) frequently, another road output also enters frequency changer circuit 6 after difference frequency frequency selection circuit 5 is selected difference frequency (noise carrier), the radio station carrier wave selects the output of circuit 7 also to enter frequency changer circuit 6 in addition, signal after frequency changer circuit 6 frequency conversions is by concentrating intermediate frequency, noise carrier is selected and back one tunnel entering signal intermediate frequency detecting circuit 9 is amplified in amplifying circuit 8 frequency-selectings, the signal that signal intermediate frequency detecting circuit 9 detects is sent into and is merged circuit 11, another road enters noise carrier detecting circuit 10, the noise voltage that noise carrier detecting circuit 10 detects enters and is merged circuit 11, be merged the output radio signals with the noise contribution of signal.
2, noise-reducing receiving circuit according to claim 1, it is characterized in that: 2 ends of transformer B2 connect the emitter-base bandgap grading of BG4 in the mixting circuit 3 in the oscillating circuit 1 by capacitor C 20,2 ends of transformer B1 are by capacitor C 7 in the oscillating circuit 2, potentiometer W1 connects the base stage of BG4, the collector electrode of BG4 connects 1 end of B4 in the difference frequency frequency selection circuit 5, and by 1 of B4,2 ends of B3 in 2 terminations and the frequency frequency selection circuit 4,6 ends of B3 are by 7 of B6, the base stage of BG5 in the 6 termination frequency changer circuits 6,4 of B4,6 termination potentiometer W2, the mid point of W2 connects 2 ends of B6, BG5, the collector electrode of BG6 connects signal intermediate frequency respectively, in the noise carrier selective frequency amplifier circuit 1 of B7,3 ends, 4 ends of B7 and 3 ends of B8 join, 2 ends of B8 and 3 ends of B9 join, 4 ends of B8 are by 5 of B9, the base stage of 4 termination BG8,7 of the logical B9 of 7 ends of B8, the base stage of 6 termination BG7, BG9, the collector electrode of BG10 meets 4 of B12 respectively, 2 ends, 3 ends of the 3 termination B13 of B12, D1 negative pole in the 6 termination signal intermediate frequency detecting circuits of B12, the positive pole of D2 in the 5 termination noise carrier detecting circuits of B13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90102382 CN1056026A (en) | 1990-04-21 | 1990-04-21 | Noise-reducing receiving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 90102382 CN1056026A (en) | 1990-04-21 | 1990-04-21 | Noise-reducing receiving circuit |
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| Publication Number | Publication Date |
|---|---|
| CN1056026A true CN1056026A (en) | 1991-11-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 90102382 Pending CN1056026A (en) | 1990-04-21 | 1990-04-21 | Noise-reducing receiving circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1066890C (en) * | 1994-06-09 | 2001-06-06 | 三星电子株式会社 | Auto-selective circuit of an intermediate frequency |
| CN100372237C (en) * | 2003-07-03 | 2008-02-27 | Lg电子株式会社 | Method for canceling noise in a mobile terminal |
| CN103077703A (en) * | 2012-12-25 | 2013-05-01 | 桂林电子科技大学 | Method and device for inhibiting dynamic noise |
-
1990
- 1990-04-21 CN CN 90102382 patent/CN1056026A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1066890C (en) * | 1994-06-09 | 2001-06-06 | 三星电子株式会社 | Auto-selective circuit of an intermediate frequency |
| CN100372237C (en) * | 2003-07-03 | 2008-02-27 | Lg电子株式会社 | Method for canceling noise in a mobile terminal |
| CN103077703A (en) * | 2012-12-25 | 2013-05-01 | 桂林电子科技大学 | Method and device for inhibiting dynamic noise |
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