CN209105191U - A kind of fixed frequency reception system of amplitude modulation - Google Patents
A kind of fixed frequency reception system of amplitude modulation Download PDFInfo
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- CN209105191U CN209105191U CN201920043603.8U CN201920043603U CN209105191U CN 209105191 U CN209105191 U CN 209105191U CN 201920043603 U CN201920043603 U CN 201920043603U CN 209105191 U CN209105191 U CN 209105191U
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Abstract
The utility model relates to a kind of fixed frequencies of amplitude modulation to receive system.System includes: host, antenna module and circuit board；The antenna module receives radio signal and is transmitted to the frequency-selecting coupling circuit on circuit board by feeder line；The frequency-selecting coupling circuit couple broadcast singal, select wanted received frequency-fixed signal, and be transmitted to the high-frequency amplifier circuit；The high-frequency amplifier circuit, which receives, amplifies the frequency-fixed signal, and is transmitted to the filter circuit；The filter circuit receives and by the noise filtering of the frequency-fixed signal and is transmitted to the local oscillator mixting circuit；The local oscillator mixting circuit is mixed the frequency-fixed signal and obtains intermediate-freuqncy signal, and is transmitted to the IF amplifier circuit；The IF amplifier circuit, which receives, amplifies the intermediate-freuqncy signal, is transmitted to the audio power amplifier circuit after demodulating audio signal；The audio power amplifier circuit carries out noise reduction and enhanced processing to the audio signal, drives the loudspeaker sounding, can receive the amplitude modulation broadcasting of fixed frequency.
Description
Technical field
The utility model relates to broadcast reception fields, receive system more particularly to a kind of fixed frequency of amplitude modulation.
Background technique
The so-called AM of amplitude modulation broadcasting, i.e. people is the first broadcast system in history.AM standard is passed by outstanding signal
Ability is sent, Yu Haiyang, mountain area, borderland and other outlying districts, and electric power and base in various disasters can be serviced well
The area that plinth communications service is destroyed.Therefore, AM broadcast system still falls within the grand strategy resource of country at this stage.For connecing
The tool for receiving radio amplitude modulated broadcast signal is usually AM receiver, and traditional AM receiver is the broadcast for receiving full frequency band
Signal, the signal quality that take into account entire frequency range just will appear the case where attending to one thing and lose sight of another, and amplitude modulation broadcasting standard is vulnerable to interference, institute
Received signal is second-rate, is unable to satisfy user demand, its audience rating is caused to keep falling.
Utility model content
Based on this, the purpose of the utility model is to provide a kind of fixed frequencies of amplitude modulation to receive system, and having can receive admittedly
Determine the good advantage of the amplitude modulation broadcasting of frequency, strong antijamming capability, the quality of reception.
A kind of fixed frequency reception system of amplitude modulation, including host, the antenna module being set to outside the host and is set to institute
State the circuit board inside host；The frequency-selecting coupling circuit being sequentially connected electrically, high-frequency amplifier circuit, filter are provided on the circuit board
Wave circuit, local oscillator mixting circuit, IF amplifier circuit, audio power amplifier circuit and loudspeaker；The antenna module receives radio
Signal is simultaneously transmitted to the frequency-selecting coupling circuit by feeder line；The frequency-selecting coupling circuit couple broadcast singal, select and are wanted
Received frequency-fixed signal, and it is transmitted to the high-frequency amplifier circuit；The high-frequency amplifier circuit, which receives, amplifies the frequency-fixed signal,
And it is transmitted to the filter circuit；The filter circuit receives and by the noise filtering of the frequency-fixed signal and is transmitted to described
Shake mixting circuit；The local oscillator mixting circuit is mixed the frequency-fixed signal and obtains intermediate-freuqncy signal, and is transmitted to the intermediate frequency and puts
Big circuit；The IF amplifier circuit, which receives, amplifies the intermediate-freuqncy signal, demodulates audio signal and is transmitted to the audio function
Electric discharge road；The audio power amplifier circuit receives the audio signal, carries out noise reduction and enhanced processing to it, drives the loudspeaker
Sounding.
Amplitude modulation described in the utility model determines frequency and receives system, has the amplitude modulation broadcasting that can receive fixed frequency, resists and do
Disturb the advantage that ability is strong, the quality of reception is good.
Further, the high-frequency amplifier circuit includes the first transformer, triode and the second transformation being sequentially connected electrically
Device；First transformer is connected to the rear end of the frequency-selecting coupling circuit, and the voltage of the frequency-fixed signal is increased and exported
To the base stage of the triode；The collector of the triode is connected to the second transformer, and emitter is connected to power cathode, institute
Triode is stated to amplify the frequency-fixed signal and export to the boosting output of the second transformer.
Further, it is additionally provided with gain setting resistor between the secondary coil and positive pole of first transformer,
For adjusting the voltage gain of the high-frequency amplifier circuit.
Further, the filter circuit is three rank filter circuits, including to be sequentially connected to the high-frequency amplifier circuit defeated
Third transformer, the 4th transformer and the 5th transformer of outlet, for improving the pure of signal for the noise filtering of frequency-fixed signal
Cleanliness, and reduce signal amplitude, preferably with rear class mixer matches.
Further, the local oscillator mixting circuit include be connected to the filter circuit output end negative gain mixer and
It is connected to the temperature compensating crystal oscillator of the negative gain mixer signal input part；The temperature compensating crystal oscillator generation local oscillation signal is transmitted to described
Negative gain mixer；The local oscillation signal and frequency-fixed signal mixing are obtained intermediate-freuqncy signal by the negative gain mixer.
Further, the local oscillator mixting circuit further includes the local oscillation signal for being connected to the temperature compensating crystal oscillator signal output end
Filter circuit；The local oscillation signal filter circuit is by the harmonic filtration of the local oscillation signal.
Further, the IF amplifier circuit includes the intermediate frequency amplifier for being connected to the local oscillator mixting circuit output end
With signal strength indicator light；The intermediate frequency amplifier has been internally integrated multiple groups amplifier；The multiple groups amplifier is by the intermediate frequency
Signal amplification；The signal strength indicator light is connected to the driving output pin of the intermediate frequency amplifier.
Further, the audio power amplifier circuit further includes the low-pass filtering for being connected to the IF amplifier circuit output end
Device and power amplifier；The low-pass filter makes an uproar high frequency entrained by audio signal that the IF amplifier circuit demodulates
Sound is transmitted to the power amplifier after filtering out；The power amplifier will be described in the voltage amplification of the audio signal and driving
Loudspeaker sounding.
Further, the antenna module includes loop antenna；The loop antenna has primary coil and secondary coil；It is described
Resonant capacitance is also parallel on primary coil.
Further, the antenna module further includes the antenna adapter for being connected to the secondary coil；The antenna is suitable
Orchestration has field-effect tube；The field-effect tube amplifies the received broadcast singal of the loop antenna.
In order to better understand and implement, according to the present invention will be described in detail below with reference to the accompanying drawings.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the front panel of host described in the utility model；
Fig. 2 is total functional block diagram that the fixed frequency of amplitude modulation described in the utility model receives system；
Fig. 3 is the connection schematic diagram of antenna module described in the utility model；
Fig. 4 is the circuit diagram of antenna adapter described in the utility model；
Fig. 5 is the schematic diagram of high-frequency amplifier circuit described in the utility model；
Fig. 6 is the schematic diagram of filter circuit described in the utility model；
Fig. 7 is the schematic diagram of local oscillator mixting circuit described in the utility model；
Fig. 8 is the schematic diagram of IF amplifier circuit described in the utility model；
Fig. 9 is the schematic diagram of audio power amplifier circuit described in the utility model.
Specific embodiment
In the description of the present invention, it should be understood that term " center ", " longitudinal direction ", " transverse direction ", "upper", "lower",
The orientation or positional relationship of the instructions such as "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outside" is
It is based on the orientation or positional relationship shown in the drawings, is merely for convenience of describing the present invention and simplifying the description, rather than indicate
Or imply that signified device or element must have a particular orientation, be constructed and operated in a specific orientation, therefore cannot understand
For limitations of the present invention.In the description of the present invention, unless otherwise indicated, the meaning of " plurality " is two or two
More than a.
Please refer to Fig. 1 and Fig. 2, wherein Fig. 1 is the structural schematic diagram of the front panel of host described in the utility model；
Fig. 2 is total functional block diagram that the fixed frequency of amplitude modulation described in the utility model receives system.
The fixed frequency of the amplitude modulation receives system, including host 10, the antenna module being set to outside the host 20 and setting
In being provided with the frequency-selecting coupling circuit 31 being sequentially connected electrically, high frequency on 10 internal circuit board 30 of host, the circuit board 30
Amplifying circuit 32, filter circuit 33, local oscillator mixting circuit 34, IF amplifier circuit 35, audio power amplifier circuit 36 and loudspeaker 37；
The antenna module 20 receives radio signal and is transmitted to the frequency-selecting coupling circuit 31 by feeder line；The frequency-selecting coupling electricity
Road 31 couples broadcast singal, selects wanted received frequency-fixed signal, and is transmitted to the high-frequency amplifier circuit 32；The high frequency
Amplifying circuit 32, which receives, amplifies the frequency-fixed signal, and is transmitted to the filter circuit 33；The filter circuit 33 will be described fixed
The noise filtering of frequency signal is simultaneously transmitted to the local oscillator mixting circuit 34；The local oscillator mixting circuit 34 is mixed to the frequency-fixed signal
Frequency obtains intermediate-freuqncy signal, and is transmitted to the IF amplifier circuit 35；The IF amplifier circuit 35, which receives, amplifies the intermediate frequency
Signal demodulates audio signal and is transmitted to the audio power amplifier circuit 36；The audio power amplifier circuit 36 receives the audio
Signal carries out noise reduction and enhanced processing to it, drives 37 sounding of loudspeaker.
Power switch 11, volume adjustment knob 12, indicator light 13, letter are provided in the front panel of 10 shell of host
Number table 14 and high-frequency gain adjusting knob 15.The indicator light 13 includes signal lamp, power lights and volume indicator light, is respectively adopted
The LED light of different colours, for power supply instruction, volume instruction and signal strength or weakness instruction；The signal table 14 for seeing in real time
Survey the power of received signal；The high-frequency gain adjusting knob 15 is for adjusting high-frequency gain.
It is the connection schematic diagram of antenna module described in the utility model please refer to Fig. 3 and Fig. 4, Fig. 3；Fig. 4 is this reality
With the circuit diagram of the novel antenna adapter.
The antenna module 20 is set to the outside of the host 10, and is placed in the stronger place of signal, for receiving
Radio amplitude modulated broadcast signal.The antenna module 20 includes loop antenna and the day for being connected to loop antenna secondary coil rear end
Line adapter.The loop antenna includes the more primary coil of wire circle and the less secondary coil of wire circle；It is described first
Resonant capacitance is also parallel on grade coil.The antenna adapter has field-effect tube；The field-effect tube has input impedance
The small characteristic of big output impedance amplifies the received broadcast singal of the loop antenna, and passes through feeder line for radio signal transmission
Frequency-selecting coupling circuit 31 inside to host are coupled.The method that this secondary coil in antenna increases adapter can have
Effect reduces noise jamming, and reduces late-class circuit to the received influence of primary coil, keeps the resonance point of primary coil obvious.
The antenna of traditional AM receiver is built in inside host, can not separate antenna and receiver, when
When audience goes for the broadcast singal of high quality, it usually needs interfered to home with radio movement smaller or outdoor remote
Place from interference source is listened to, and is made troubles to audience.Therefore, this amplitude modulation is determined in frequency reception system that antenna is external, can place
In the outdoor place far from interference source to reduce interference.In addition, the antenna of traditional AM receiver is all made of magnetic antenna, because
Magnetic antenna is all more sensitive to magnetic field signal and electric field signal, therefore using in the present embodiment is influenced small ring day by electric field signal
Interference can be greatly lowered in line in this way, obtain the better quality of reception.
The frequency-selecting coupling circuit 31 couple broadcast singal, select wanted received frequency-fixed signal, and are transmitted to described
High-frequency amplifier circuit 32.Specifically, the frequency-selecting coupling circuit 31 are connected with a controllable impedance, and adjusting this inductance can be selected
Frequently.In the present embodiment, the amplitude modulated broadcast signal that selected frequency is 621K is received, and can limit the garbage signal other than 621K
System.In addition, can also change frequency point according to actual needs, circuit theory is also the same.
Referring to Fig. 5, Fig. 5 is the schematic diagram of high-frequency amplifier circuit described in the utility model.
The high-frequency amplifier circuit 32 receives and amplifies the frequency-fixed signal, and the frequency-fixed signal is transmitted to the filter
Wave circuit 33.Specifically, in the present embodiment, the high-frequency amplifier circuit 32 includes the first transformer T1 being sequentially connected electrically, three
Pole pipe Q1 and the second transformer T2.The triode Q1 is NPN triode, concrete model 2SC3358, in addition, the triode
It is also possible to other models.The first transformer T1 is connected to the rear end of the frequency-selecting coupling circuit 31, and the fixed frequency is believed
Number voltage increase and export to the base stage of the triode Q1；Its collector is connected to the second transformer T2, and emitter passes through
R5 and C16 is connected to power cathode, and the frequency-fixed signal is amplified and exported to the second transformer T2 by the triode Q1 to boost
Output.The high-frequency amplifier circuit 32 can be good at matching with prime, and filter out unwanted signal, such as local stronger
The signals such as 747K, 756K, and the signal after filtering clutter is transmitted to the amplification that transformer T2 carries out signal voltage.Further
Ground is also additionally provided with gain setting resistor R1 between the secondary coil and positive pole of the first transformer T1, passes through tune
Save the gain amplifier of the adjustable amplifying stage of resistance value of R1.
Referring to Fig. 6, Fig. 6 is the schematic diagram of filter circuit described in the utility model.
The filter circuit 33 receives and by the noise filtering of the frequency-fixed signal and is transmitted to the local oscillator mixting circuit
34.Specifically, the filter circuit 33 is three rank filter circuits, including is sequentially connected to 32 output end of high-frequency amplifier circuit
Third transformer T3, the 4th transformer T4 and the 5th transformer T5, and the input of voltage devices at different levels or output end setting filter
Wave capacitor.The filter circuit 33 further improves the degree of purity of frequency-fixed signal, reduces tyre noise and interference, through filtering
Circuit 33 filter after, the amplitude of frequency-fixed signal can be reduced to original 60%, can preferably with the mixer matches of rear class.
Referring to Fig. 7, Fig. 7 is the schematic diagram of local oscillator mixting circuit described in the utility model.
The fixed frequency of this amplitude modulation receives system and uses superheterodyne circuit, and a local oscillation signal is needed to be mixed with received signal
Frequently, difference frequency goes out the intermediate-freuqncy signal of 465K.Therefore, this amplitude modulation is determined to be provided with local oscillator mixting circuit 34 in frequency reception system.Described
Vibration mixting circuit 34 includes being connected to the negative gain mixer 343 of 33 output end of filter circuit and being connected to the negative gain
The temperature compensating crystal oscillator 341 of 343 signal input part of frequency mixer；The temperature compensating crystal oscillator 341 generates local oscillation signal and is transmitted to the negative gain
Frequency mixer 343；The local oscillation signal and the mixing of received frequency-fixed signal are obtained intermediate-freuqncy signal by the negative gain mixer 343.
Being computed this local oscillation signal is 1086K (621K+465K=1086K), to simplify circuit and mentioning high-frequency steady
It is qualitative, the temperature compensating crystal oscillator of a 1086K is had subscribed in the present embodiment.But the local oscillation signal of temperature compensating crystal oscillator output carries
Harmonic wave.Therefore, further, the local oscillator mixting circuit 34 further includes being connected to 341 signal output end of temperature compensating crystal oscillator
Local oscillation signal filter circuit 342；The local oscillation signal filter circuit 342 is pure to obtain by the harmonic filtration of the local oscillation signal
Net local oscillation signal.The local oscillation signal filter circuit 342 includes being sequentially connected to 341 signal output end of temperature compensating crystal oscillator
6th transformer T6, the 7th transformer T7 and the 8th voltage device T8, and the input of each transformer or output end are provided with filter
Wave capacitor.
The negative gain mixer 343 is diode loop mixer, and concrete model is SBL-3 passive frequency mixer, due to
SBL-3 passive frequency mixer is negative gain, i.e. for signal after frequency mixer, amplitude can be smaller without overloading than before mixing.
Referring to Fig. 8, Fig. 8 is the schematic diagram of IF amplifier circuit described in the utility model.
The IF amplifier circuit 35 includes the intermediate frequency amplifier for being connected to 34 output end of local oscillator mixting circuit
TA7640 and signal strength indicator light D1；The intermediate frequency amplifier TA7640 has been internally integrated multiple groups amplifier；The multiple groups are put
Big device amplifies the intermediate-freuqncy signal；The driving output that the signal strength indicator light D1 is connected to the intermediate frequency amplifier is drawn
Foot.The intermediate-freuqncy signal is accessed from the signal input pin P13 of TA7640, simultaneously by the multiple groups amplifier amplification inside TA7640
From pin P9 output audio signal to the audio power amplifier circuit 36 after demodulation.
Referring to Fig. 9, Fig. 9 is the schematic diagram of audio power amplifier circuit described in the utility model.
The audio power amplifier circuit 36 further include be connected to 35 output end of IF amplifier circuit low-pass filter and
Power amplifier；The low-pass filter is transmitted to the power amplification after filtering out the high-frequency noise that the audio signal carries
Device；The power amplifier is by the voltage amplification of the audio signal and drives 37 sounding of loudspeaker.Specifically, described low
The RC low-pass filter for the capacitor composition that bandpass filter is the resistance that 3 resistance values are 400 Europe and 3 capacitances are 0.1uF, with filter
Except the noise signal that frequency is 4K or more.When broadcast signal quality reaches normal level, noise can be much smaller, at this time if worried
Dolby circuit influences sound quality, can skip this circuit, for this purpose, being also connected to a noise reduction switch S1 in circuit, and will
The noise reduction switch is designed to toggle switch, is set on the postposition panel of the host housing.The IF amplifier circuit 35 is defeated
Audio signal out is sent to the power amplification electricity being made of power amplifier LM386 after RC low-pass filter noise reduction process
The amplification of audio power is carried out in road, amplified signal can drive the loudspeaker sounding.
Hereinafter, being described from the assessment that the fixed frequency of amplitude modulation described in the utility model receives system, frequency is determined into amplitude modulation and is received
The ICF-SW7600G of system and Sony, the YB400 of root moral, mountain into PR-D3L, Dodge automobile audio, intelligence run automobile audio etc.
Generally acknowledge that the outstanding equipment of receptivity carries out Transverse Evaluation.The weak place of pickup electrode is had chosen in assessment experiment, is received
621K signal is tested and assessed；Artificial addition interference source is simultaneously come under the conditions of testing poor reception, the anti-interference energy of Devices to test
Power.Specific assessment is divided into two parts progress: first is that the test of the antenna of to-be-detected machine collocation original machine, second is that the loop antenna of the design is matched
The machine for closing energy external antenna is tested.Test result is as follows shown in table 1 for the antenna of to-be-detected machine collocation original machine:
Table 1
Loop antenna and fixed frequency receive the outstanding reception ability of system as can be seen from Table 1, can capture other machines use
The extremely low signal that original machine antenna can not sense.
The result that the machine of the loop antenna cooperation energy external antenna of the design is tested is as shown in table 2 below:
Table 2
From table 2 statistics indicate that, the loop antenna collocation comparison type that the fixed frequency of this amplitude modulation receives system can be effectively improved pair
Than the reception ability of type, and this amplitude modulation is determined frequency reception system and is still able to maintain in the case where comparing machine and all employing loop antenna
Leading superiority, and it is made fine in the inhibition of audio high band noise.In terms of anti-interference ability, artificially it joined in assessment dry
Source is disturbed, test result is ICF-SW7600G and Dodge vehicle device of the quality of reception better than Sony that frequency receiver is determined in the amplitude modulation, and intelligence is run
Vehicle device to the maximum extent falls the AF panel other than frequency band with the outstanding algorithm of DSP, thus by the " noise made in coughing or vomiting caused by interfering
" sound is less, it is quite a lot of in sense of hearing, but useful signal determine the promotion that frequency reception system has no substance compared to this amplitude modulation.To sum up institute
It states, it is all very outstanding that the fixed frequency of this amplitude modulation receives performance of the system in terms of the antenna and in terms of circuit design, has preferable receive
Quality.
The fixed frequency of amplitude modulation described in the utility model receives system, passes through the improvement to antenna and processing circuit at different levels, tool
There is preferable anti-interference ability, listening quality is good, has cracked amplitude modulation broadcasting and has received difficult quagmire.
Above-described embodiments merely represent several embodiments of the utility model, the description thereof is more specific and detailed,
But it cannot be understood as the limitations to utility model patent range.It should be pointed out that for the common skill of this field
For art personnel, without departing from the concept of the premise utility, various modifications and improvements can be made, these are belonged to
The protection scope of the utility model.
Claims (10)
1. a kind of fixed frequency of amplitude modulation receives system, it is characterised in that: including host, the antenna module being set to outside the host and
The circuit board being set to inside the host；The frequency-selecting coupling circuit being sequentially connected electrically are provided on the circuit board, high frequency is put
Big circuit, filter circuit, local oscillator mixting circuit, IF amplifier circuit, audio power amplifier circuit and loudspeaker；The antenna module connects
It receives radio signal and the frequency-selecting coupling circuit is transmitted to by feeder line；The frequency-selecting coupling circuit couple broadcast singal,
Wanted received frequency-fixed signal is selected, and is transmitted to the high-frequency amplifier circuit；The high-frequency amplifier circuit receives described in amplification
Frequency-fixed signal, and it is transmitted to the filter circuit；The filter circuit receives and by the noise filtering and biography of the frequency-fixed signal
Transport to the local oscillator mixting circuit；The local oscillator mixting circuit is mixed the frequency-fixed signal and obtains intermediate-freuqncy signal, and is transmitted to
The IF amplifier circuit；The IF amplifier circuit, which receives, amplifies the intermediate-freuqncy signal, demodulates audio signal and is transmitted to
The audio power amplifier circuit；The audio power amplifier circuit receives the audio signal, and carries out noise reduction and enhanced processing to it, drives
Move the loudspeaker sounding.
2. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the high-frequency amplifier circuit includes successively
The first transformer, triode and the second transformer of electrical connection；First transformer is connected to the frequency-selecting coupling circuit
The voltage of the frequency-fixed signal is increased and is exported to the base stage of the triode by rear end；The collector of the triode connects
To the second transformer, emitter is connected to power cathode, and the frequency-fixed signal is amplified and exported to second and become by the triode
Depressor boosting output.
3. the fixed frequency of amplitude modulation according to claim 2 receives system, it is characterised in that: the secondary coil of first transformer
Gain setting resistor is additionally provided between positive pole.
4. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the filter circuit is three rank filtered electricals
Road, third transformer, the 4th transformer and the 5th transformer including being sequentially connected to the high-frequency amplifier circuit output end.
5. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the local oscillator mixting circuit includes connection
In the filter circuit output end negative gain mixer and be connected to the negative gain mixer signal input part temperature compensation it is brilliant
Vibration；The temperature compensating crystal oscillator generates local oscillation signal and is transmitted to the negative gain mixer；The negative gain mixer is by the local oscillator
Signal and frequency-fixed signal mixing obtain intermediate-freuqncy signal.
6. the fixed frequency of amplitude modulation according to claim 5 receives system, it is characterised in that: the local oscillator mixting circuit further includes connecting
It is connected to the local oscillation signal filter circuit of the temperature compensating crystal oscillator signal output end；The local oscillation signal filter circuit believes the local oscillator
Number harmonic filtration.
7. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the IF amplifier circuit includes connection
In the intermediate frequency amplifier and signal strength indicator light of the local oscillator mixting circuit output end；The intermediate frequency amplifier has been internally integrated
Multiple groups amplifier；The multiple groups amplifier amplifies the intermediate-freuqncy signal；The signal strength indicator light is connected to the intermediate frequency
The driving output pin of amplifier.
8. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the audio power amplifier circuit further includes connecting
It is connected to the low-pass filter and power amplifier of the IF amplifier circuit output end；The low-pass filter puts the intermediate frequency
High-frequency noise entrained by the audio signal that big circuit demodulates is transmitted to the power amplifier after filtering out；The power amplification
Device is by the voltage amplification of the audio signal and drives the loudspeaker sounding.
9. the fixed frequency of amplitude modulation according to claim 1 receives system, it is characterised in that: the antenna module includes loop antenna；
The loop antenna has primary coil and secondary coil；Resonant capacitance is also parallel on the primary coil.
10. the fixed frequency of amplitude modulation according to claim 9 receives system, it is characterised in that: the antenna module further includes connection
In the antenna adapter of the secondary coil；The antenna adapter has field-effect tube；The field-effect tube is by the ring day
The received broadcast singal amplification of line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920043603.8U CN209105191U (en) | 2019-01-10 | 2019-01-10 | A kind of fixed frequency reception system of amplitude modulation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920043603.8U CN209105191U (en) | 2019-01-10 | 2019-01-10 | A kind of fixed frequency reception system of amplitude modulation |
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| Publication Number | Publication Date |
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| CN209105191U true CN209105191U (en) | 2019-07-12 |
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| CN201920043603.8U Expired - Fee Related CN209105191U (en) | 2019-01-10 | 2019-01-10 | A kind of fixed frequency reception system of amplitude modulation |
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| Country | Link |
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