CN1295867C - High fidelity audio signal amplifying method - Google Patents
High fidelity audio signal amplifying method Download PDFInfo
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- CN1295867C CN1295867C CNB031252710A CN03125271A CN1295867C CN 1295867 C CN1295867 C CN 1295867C CN B031252710 A CNB031252710 A CN B031252710A CN 03125271 A CN03125271 A CN 03125271A CN 1295867 C CN1295867 C CN 1295867C
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Abstract
The present invention relates to a method for amplifying a high-fidelity audio signal based on radio frequency transmission. One parameter (such as frequency, phase position or amplitude) of the radio frequency signal is modulated by the amplified audio signal, and thus, a radio frequency signal carried with the amplified audio information is obtained. The radio frequency signal is amplified by a high-frequency amplifier, and the amplified radio frequency signal is demodulated to be reduced into an audio signal. The high-frequency signal is amplified, and simultaneously the audio signal is indirectly amplified.
Description
Technical field
The present invention relates to the audio signal amplifying technique.Especially based on the Hi-Fi audio signal amplification method and the corresponding audio signal amplifier of radio frequency transmission.
Background technology
In Bao Gaozhen audio frequency amplifier field, existing audio signal amplification mode all is the citation form that adopts the wide-band linearity direct modeling to amplify.Though having of amplifier is varied in form, as the feedback amplifying type, feedforward amplifying type (current dump of being called formula is also arranged), predistortion amplification correction formula etc.; And the operating state difference of amplifier, category-A, AB class, category-B etc. are arranged; The structure difference of amplifier has monofocal, PP (symmetry is recommended) formula, and SEPP (SEPP single ended push-pull) formula, and SRPP etc.; The components and parts difference that adopts has vacuum tube amplifier, bipolar transistor amplifier, field effect transistor (FET) amplifier, and mixer amplifier etc.But its citation form is the same all is to belong to the type of input signal directly being simulated amplification.The common shortcoming of the amplifier of this type is that the open loop frequency scope of amplifier is narrow, and response speed is slow, and poor linearity needs to adopt variety of way to come correcting distortion.As feedback amplifier, reduce distortion and widening frequency band, have the increase depth of feedback only, but because there is the problem of stable aspect in the amplifier after the closed loop, need carry out phase compensation to it, cause the amplifier open loop frequency low, response speed is slow, when amplifier can't be followed the tracks of the fast-changing signal of telecommunication, can cause amplifier moment overload and the generation transient distortion.This class A amplifier A another one common drawback is direct amplification signal, amplifier for PP or SEPP type, its processing method is the synthetic more complete signal of telecommunication after becoming positive half cycle and negative half period separately to amplify signal segmentation, because the characteristic (characteristic that comprises DC power supply) of both sides amplifier is incomplete same, the signal of telecommunication after synthetic can produce distortion (comprising phase distortion), if the pace of change of signal is faster than the response speed of amplifier, this distortion can't reduce by feedback so.Though the overall process of amplifying for monofocal amplifier signal is all in same amplifier, but the positive half cycle of signal and negative half period amplification process still are in the different operating state of amplifier, the positive half cycle of signal is in from big electric current to saturated operating state from 0 to peak amplifier, the negative half period of signal is in from little electric current to the operating state of ending from 0 to peak amplifier, different its characteristics of operating state are also inequality for same amplifier, as impedance, mutual conductance, rising and fall time etc., this also can cause distortion.Also there is non-direct modeling to amplify the mode of audio signal, as directly audio signal being carried out pulse sampling, adopt the D class A amplifier A of PWM technology and the digitized audio amplifier of employing PCM technology, this class A amplifier A can be referred to as switching amplifier, because amplifier is not directly to amplify audio signal, so it has many advantages: efficient height, amplifier itself directly do not produce distortion etc. to the audio signal of being amplified.This class A amplifier A can obtain perfect amplification effect in theory, but because the influence of various complicated factors, its actual acoustics is unsatisfactory at present, even not as good as some analogue amplifiers.Though the frequency of sound wave scope that people's ear can be awared only is 20-20000Hz, but the signal of telecommunication that actual musical sound and language sound wave are obtained after by sound one power conversion system is very complicated, it is not single monochromatic wave, we know that its frequency spectrum of audio signal of musical sound and language is very wide by fourier transform, are far above the scope of 20-20000Hz.
Summary of the invention
The object of the present invention is to provide a kind of non-direct modeling to amplify the method for audio signal, this method is audio signal directly to be loaded in the radiofrequency signal transmit, thereby obtains the audio amplification signal of high-fidelity.
Hi-Fi audio signal amplification method provided by the present invention, be in the audio signal amplifier that in same circuit, constitutes by radio-frequency modulator, radio frequency amplifier, radio-frequency (RF) demodulator, audio signal to be amplified is modulated the frequency of radiofrequency signal or phase place or amplitude, acquisition carries the radiofrequency signal that remains to be amplified audio signal, amplify this radiofrequency signal by radio frequency amplifier, radiofrequency signal after will amplifying is again reconciled and is restored audio signal, when having amplified radiofrequency signal, audio signal has also obtained amplification indirectly.
The audio signal amplification method that the present invention is based on radio frequency transmission is compared with the technical method that audio signal and digitized audio amplification are amplified in common direct modeling, have many superiority: response speed is fast, audio signal loads in the radiofrequency signal amplifies, the high several magnitude of frequency of the comparable audio signal of frequency of radiofrequency signal, therefore the transmission speed of audio signal amplification process is also faster than direct modeling amplification mode, and this is very favourable to reducing distortion; That the influence of audio signal is amplified mode than direct modeling is little for the characteristic of active device and passive device in the amplifier; Scalable audio frequency upper limiting frequency is only relevant with the passband width of radio frequency amplifier, wants high more than direct modeling amplification mode; Compare with the digitized audio amplifier, what native system amplified is monochromatic wave, non-switching signal, less demanding to active device, and operating frequency is more much higher than the sample frequency of digitized audio, frequency band is narrow, noise is little, amplify, coupling and control easily.
Realizing that the inventive method provides corresponding Hi-Fi audio signal amplifier, is to be made of in same circuit radio-frequency modulator, radio frequency amplifier, radio-frequency (RF) demodulator, wherein:
Radio-frequency modulator comprises radio-frequency signal source, radiofrequency signal modulating unit, frequency multiplication or frequency conversion equifrequent converter unit circuit, radio-frequency signal source is to produce the required radiofrequency signal of described audio signal amplifier by oscillator, audio signal converts unmodulated radiofrequency signal to amplitude-modulated signal or FM signal by the radiofrequency signal modulating unit, and modulated radio frequency amplitude-modulated signal or FM signal become the higher or lower signal of frequency by frequency multiplication or frequency conversion equifrequent converter unit circuit conversion; Radio frequency amplifier closes for the high frequency linearity amplifier comprises the amplification of rf signal, the lotus root of rf signal between amplifier stage, coupling and bandwidth control circuit; Radio-frequency (RF) demodulator comprises after modulated radiofrequency signal demodulating unit circuit, the filtering demodulation radio-frequency filter of carrier frequency composition, the element circuit of the DC component in the audio signal after the isolate demodulation in the audio signal.
Audio signal has following several to the modulator approach of radiofrequency signal: 1, amplitude modulation mode; 2, mode of frequency regulation; 3, pm mode.Corresponding demodulation method is: the amplitude modulation mode is recovered audio signal with envelope detector; Frequency modulation and pm mode recover audio signal with frequency discriminator or phase discriminator.
When rf modulations of the present invention adopted Modulation and Amplitude Modulation AM mode, the output amplitude that is meant radiofrequency signal in radio-frequency modulator changed with the size of input audio signal; Amplitude modulaor can be the carrier frequency type is arranged, to suppress one or more the combination in carrier frequency type, the QAM type amplitude modulaor, and corresponding radio-frequency (RF) demodulator is for detecting the element circuit of radiofrequency signal amplitude variations.The method that obtains amplitude-modulated signal is audio signal to be superposeed multiply each other with CF signal after the DC component.If audio signal is V
AF=V
AMCOS Ω t, CF signal V
RF=V
RMCOS ω t, m=V
AM/ V
RMBe modulation, (m≤1).The back amplitude-modulated signal that multiplies each other is V=V
RM(1+mCOS Ω t) * COS ω t, the amplitude of CF signal COS ω t becomes amplitude modulation principle that Here it is with audio signal (1+mCOS Ω t).Can adopt common amplitude modulaor in the application: as the grid modulation method of electron tube; The negative electrode modulation method; The anode modulation method; Screen or suppressor grid modulation method; Hybrid modulation method etc.Transistorized base stage, emitter, collector modulation method etc.The grid of field effect transistor, source electrode and drain modulation method etc.Also available multiplication formula amplitude modulaor; Dual gate FET multiplication amplitude modulator; The amplitude modulaor that analog multiplier constitutes.Or realize the generation of amplitude-modulated signal with quadrature amplitude modulation mode (QAM) mode.Amplitude modulated radio frequency signal adopts linear tuned amplifier to amplify, radio frequency amplifier with tuning manner high efficiency, coupling easily, narrow, the interference of passband and noise is little, distortion is low.The tuned amplifier operating state can be Class A, Class B or Class C, and is from lowering distortion, realizing the angle consideration that HD Audio is reset, best with the Class A operating state.The demodulation mode of amplitude-modulated signal has: direct detection formula, the method that amplitude modulated radio frequency signal is directly carried out rectification with high-frequency diode are reduced audio frequency; The coherent detection formula is reduced audio frequency with the synthetic method of the side frequency of former carrier frequency signal and amplitude-modulated signal.Audio signal after the demodulation also contains r-f component and DC component, needs filtering to remove r-f component and the isolated DC component could obtain pure audio signal, and filtering is with RC, RL, filters such as RLC, LC, isolated DC component RC.
When rf modulations of the present invention adopts the frequency modulation(FM) mode, be meant in radio-frequency modulator radiofrequency signal output frequency change with the size of input audio signal.The method that realizes this frequency modulation function has: direct frequency modulation method FM (also claiming the frequency modulation method), indirect frequency modulation method PM (also claiming the phase modulation method).The direct frequency modulation genealogy of law refers to thereby audio signal changes frequency of oscillation to obtain the method for FM signal by changing reactance parameter in the radio-frequency oscillator oscillation circuit, thereby the indirect frequency modulation genealogy of law refers to go after by integrating circuit the phase place of modulated radio signal to obtain the method for FM signal indirectly again audio signal.The radio frequency amplifier that amplifies FM signal is the same with the radio frequency amplifier of amplitude-modulated wave, and it is big that bandwidth is wanted.FM demodulator is frequency discriminator or phase discriminator, the FM signal medium frequency can be changed the element circuit that is converted to corresponding amplitude variations.Its principle is that frequency discriminator has the resonant tank that is tuned at 3 different frequencies, one is tuned on the carrier frequency fo, one is tuned at than on the high frequency of fo, another is tuned at than on the low frequency of fo, thus when frequency input signal changes because the resonant tank off resonance changes the amplitude of output signal detects envelope with the amplitude detection device and reduce audio signal.Audio signal behind the fm demodulation also contains high frequency composition and DC component, also needs filtering to remove r-f component and the isolated DC component could obtain pure audio signal, and filtering is with RC, RL, filters such as RLC, LC, isolated DC component RC.
The purpose that the audio signal that obtains after the demodulation filtering is fed back to radio-frequency modulator in described audio signal amplifier is further to reduce noise and reduce distortion.Realize that audio signal amplifier of the present invention both can be designed to the independently voltage amplifier of audio frequency preamplifier, driving simulated power amplifying unit, also can be designed to directly to drive the audio-frequency power amplifier of loud speaker.
Description of drawings:
Fig. 1 is a basic principle block diagram of the present invention.
Fig. 2 is the audio frequency preamplifier circuit theory diagrams of mode of frequency regulation work of the present invention.
Fig. 3 is the audio frequency preamplifier circuit theory diagrams of amplitude modulation mode of the present invention work.
Fig. 4 is the audio-frequency power amplifier circuit theory diagrams of amplitude modulation mode of the present invention work.
Embodiment
Specifically describe below in conjunction with accompanying drawing:
Fig. 2 is the audio frequency preamplifier circuit theory diagrams according to the designed mode of frequency regulation work of the principle of the invention, Q1, Q2, Q3 and peripheral cell constitute frequency modulator among Fig. 2, wherein Q1 and peripheral cell constitute very high frequency(VHF) source oscillation signal and frequency modulator, audio signal directly is added to variable capacitance diode D1, thereby makes the electric capacity of D1 with the audio signal variation frequency of oscillation of oscillator be changed.FM signal is added to the frequency changer circuit of being made up of Q2, Q3 through C5, is the lower intermediate-freuqncy signal of frequency with very high frequency(VHF) signal transformation, and Q3 is the local oscillation signal source, and Q2 is a frequency mixer.The double tunning linear discriminator that intermediate-freuqncy signal is made of T5, C25, C27, C28, D2, D3, R18, R19 after the two-stage radio-frequency amplifier of Q4, Q5 and peripheral cell composition amplifies is separated FM signal and is transferred to recover audio signal.The effect of C29, C30 is the carrier frequency composition in the audio signal after the filtering detection, and the effect of C31, C32, R20, R21 is the DC component in the audio signal after the isolation detection.
Fig. 3 is the audio frequency preamplifier circuit theory diagrams according to the designed amplitude modulation mode work of the principle of the invention, Q1, Q2 and peripheral cell constitute amplitude modulaor generation amplitude-modulated signal among Fig. 3, Q1 and peripheral cell constitute radio-frequency signal source, and dual gate FET Q2 and peripheral cell constitute the radio frequency amplitude modulator.The envelope detector that amplitude-modulated signal is made up of D1, R11, C12 after amplifying through Q3, Q4 two-stage radio-frequency amplifier recovers audio signal, and the effect of C13, R12 is the DC component in the audio signal after the isolation detection.
Fig. 4 is the audio-frequency power amplifier circuit theory diagrams according to the designed amplitude modulation mode work of the principle of the invention, amplitude modulaor is made of Q1, V1 and peripheral cell among Fig. 4, Q1 and peripheral cell constitute radio-frequency signal source, pentode V1 and peripheral cell constitute the radio frequency amplitude modulaor of grid modualtion, and radio frequency amplifier is made of V2, V3 and peripheral cell.The all-wave amplitude modulation demodulation circuit that the radiofrequency signal of T4 output is formed through D1, D2, D3, D4 detects the amplitude-modulated wave envelope part that is loaded with audio-frequency information, form after the filter filtering detection carrier frequency composition in the audio signal with the reduction audio signal by R8, C12, L2, C13, the effect of C14, R9 is to isolate the DC component in the audio signal after the detection.R10 is a feedback resistance, and the audio signal of output is added to the negative electrode of V1 through R10, forms the outer ring negative feedback with further reduction distortion with reduce noise.Obtain to drive the audio signal of loud speaker from the R9 two ends.
Claims (5)
1. Hi-Fi audio signal amplification method, in the audio signal amplifier that it is characterized in that in same circuit, constituting by radio-frequency modulator, radio frequency amplifier, radio-frequency (RF) demodulator, audio signal to be amplified is modulated the frequency of radiofrequency signal or phase place or amplitude, acquisition carries the radiofrequency signal that remains to be amplified audio signal, amplify this radiofrequency signal by radio frequency amplifier, radiofrequency signal after will amplifying is again reconciled and is restored audio signal, and audio signal has also obtained amplification indirectly when having amplified radiofrequency signal.
2. according to the described Hi-Fi audio signal amplification method of claim 1, it is characterized in that rf modulations is to adopt the Modulation and Amplitude Modulation mode, the output amplitude of radiofrequency signal changes with the size of input audio signal in the radio-frequency modulator; Amplitude modulaor can be the carrier frequency type is arranged, to suppress one or more the combination in carrier frequency type, the QAM type amplitude modulaor, and corresponding radio-frequency (RF) demodulator is for detecting the element circuit of radiofrequency signal amplitude variations.
3. according to the described Hi-Fi audio signal amplification method of claim 1, it is characterized in that rf modulations is to adopt the frequency modulation(FM) mode, the output frequency of radiofrequency signal changes with the size of input audio signal in the radio-frequency modulator, thereby can adopt audio signal changes frequency of oscillation to obtain the direct frequency modulation method of FM signal by changing in the radio-frequency oscillator reactance parameter in the oscillation circuit, thereby or adopt and to go after by integrating circuit the phase place of modulated radio signal to obtain the indirect frequency modulation method of FM signal again audio signal, corresponding radio-frequency (RF) demodulator is for changing the element circuit that be converted to corresponding amplitude variations with the radiofrequency signal medium frequency.
4. according to the described Hi-Fi audio signal amplification method of claim 1, it is characterized in that being designed to the independently voltage amplifier of audio frequency preamplifier, driving simulated power amplifying unit, or be designed to directly to drive the audio-frequency power amplifier of loud speaker.
5. a Hi-Fi audio signal amplifier is characterized in that being made of in same circuit radio-frequency modulator, radio frequency amplifier, radio-frequency (RF) demodulator, wherein:
Radio-frequency modulator comprises radio-frequency signal source, radiofrequency signal modulating unit, frequency conversion unit circuit, radio-frequency signal source is to produce the required radiofrequency signal of described audio signal amplifier by oscillator, audio signal converts unmodulated radiofrequency signal to amplitude-modulated signal or FM signal by the radiofrequency signal modulating unit, and modulated radio frequency amplitude-modulated signal or FM signal become the higher or lower signal of frequency by the frequency conversion unit circuit conversion; Radio frequency amplifier closes for the high frequency linearity amplifier comprises the amplification of rf signal, the lotus root of rf signal between amplifier stage, coupling and bandwidth control circuit; Radio-frequency (RF) demodulator comprises after modulated radiofrequency signal demodulating unit circuit, the filtering demodulation radio-frequency filter of carrier frequency composition, the element circuit of the DC component in the audio signal after the isolate demodulation in the audio signal.
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| CNB031252710A CN1295867C (en) | 2003-08-12 | 2003-08-12 | High fidelity audio signal amplifying method |
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| CNB031252710A CN1295867C (en) | 2003-08-12 | 2003-08-12 | High fidelity audio signal amplifying method |
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| CN1489283A CN1489283A (en) | 2004-04-14 |
| CN1295867C true CN1295867C (en) | 2007-01-17 |
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| CN103873005B (en) * | 2012-12-10 | 2017-10-24 | 北京普源精电科技有限公司 | Radio-frequency signal source and its method of work |
| CN110971258A (en) * | 2019-11-15 | 2020-04-07 | 苏炜 | Audio signal amplification method |
| CN110972052A (en) * | 2019-12-06 | 2020-04-07 | 久心医疗科技（苏州）有限公司 | Audio self-checking circuit and self-checking method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2194569Y (en) * | 1994-03-20 | 1995-04-12 | 陈安南 | Wireless two-direction diagram and words data transmission device |
| CN1113621A (en) * | 1994-04-26 | 1995-12-20 | 日本电气株式会社 | Radio station apparatus and signal transmission method thereof |
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2003
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2194569Y (en) * | 1994-03-20 | 1995-04-12 | 陈安南 | Wireless two-direction diagram and words data transmission device |
| CN1113621A (en) * | 1994-04-26 | 1995-12-20 | 日本电气株式会社 | Radio station apparatus and signal transmission method thereof |
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