CN2500031Y

CN2500031Y - New radio receiver

Info

Publication number: CN2500031Y
Application number: CN 01251062
Authority: CN
Inventors: 郭建军
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-10-19
Filing date: 2001-10-19
Publication date: 2002-07-10
Anticipated expiration: 2011-10-19

Abstract

The utility model discloses a novel radio, pertaining to the field of communication and broadcast, mainly resolving the problem that the reception effect of a wireless radio is poor in the medium and short wave bands, and the noise is big. The radio is applied to receiving and processing high frequency intermittent wave signal transmitted by the medium and short wave band transmitter and modulated by duty cycle. Mainly, a high-frequency intermittent wave signal processing and demodulating circuit is provided on the base of the prior amplitude modulation (AM) radio, and by adding this circuit, strong anti-interference performance and high fidelity are attributed to the radio. The sensitivity thereof is identical with that of frequency modulation (FM) radios, and times higher than that of the medium and short wave AM radio. The utility model is a novel and well-liked radio which is easy to be manufactured and popularized.

Description

A kind of late model radio

One, technical field

This novel radio broadcasting field that belongs to particularly is applicable to the late model radio of short-and-medium wave band.

Two, background technology

Medium wave (MW) is the broadcast band that extensively adopt in present countries in the world and area.Be mainly used in domestic, inside the province, the broadcasting of middle distance such as provincialism.

Shortwave (SW) utilizes the outer surface ionosphere multihop propagation signal of the earth, and the broadcasting coverage distance is far away.Adopted as the international broadcasting wave band by countries in the world, be widely used in military affairs, civilian and ham radio broadcast communication simultaneously again.

Utilize the in-plant high-fidelity broadcast system of ultrashort wave frequency modulation (FM) in addition in addition, propagate with linear fashion, coverage is about tens kilometers usually.Be that quantity is maximum, the broadcast system that volume is best.Disadvantage is exactly that propagation distance is too near.Though and the intermediate waves propagation distance is far.But the amplitude modulation standard that adopts is subject to disturb at present.Especially the radio reception effect lower tone of short-wave band, noise is big, sounds unpleasant.This is strong and weak the variation along with the audio frequency signal amplitude power changes and respective change of amplitude of the high frequency radio wave of amplitude modulation standard, and the strong and weak objective condition that is subjected to natural environment easily that changes of high frequency radio wave amplitude is disturbed.

The amplitude of above-mentioned said radio wave is subjected to the interference of objective environment easily.But the radio broadcasting of frequency modulation standard can only be applicable on the high-frequency modulation system of ultra-short wave band.Low frequency for short-and-medium wave band is just inapplicable.So the broadcasting of the radio communication of short-and-medium wave band does not up to the present also have a kind of high-fidelity broadcast system of strong anti-interference performance.

Summary of the invention

This novel purpose provides and a kind ofly can solve short-and-medium wave band radio communication broadcasting equipment and have lower tone, problem that noise is big, and develops highly sensitive, strong interference immunity, the late model radio that fidelity is high.

For realizing the purpose of invention, take following measure technically:

This late model radio, the high-frequency amplifier circuit that is linked in sequence between it comprises, frequency converter intermediate frequency amplifier circuit, signal processing and conciliation circuit, the connected loud speaker of low-frequency amplifier circuit, described signal processing and demodulator circuit are the circuit of the high frequency discontinuous wave being handled demodulation

This novel compared with prior art beneficial effect is as follows:

A, this broadcast receiver are applicable to the radio high frequency discontinuous wave signal that receives and handle short-and-medium wave band double modulation transmitter emission.Mainly be on the basis of original amplitude-modulation receiver, to be provided with to handle circuit with demodulation to high frequency discontinuous wave signal, increase this circuit after, make this broadcast receiver have stronger anti-interference and high fidelity.

B, this wireless sensitivity are identical with FM receiver, and be high doubly more a lot of than intermediate waves amplitude-modulation receiver; Be the novel of a kind of easy production and popularization, the broadcast receiver that is loved by the people.

Four, description of drawings

Fig. 1 is this novel overall block diagram;

Other plants the novel overall block diagram to Fig. 2 for Fig. 1;

Fig. 3 circuit theory diagrams that to be Fig. 1 signal processing be connected with shaping circuit with demodulator circuit;

Fig. 4 is the circuit theory diagrams of second kind of shaping circuit of Fig. 3;

Fig. 5 is the envelope detector circuit theory diagrams in the third signal processing of Fig. 2 and the demodulator circuit;

Fig. 6 is the secondary demodulation circuit theory diagrams.

Five, embodiment

Referring to Fig. 1～6, this late model radio, can be handled and demodulator circuit, the connected loud speaker of low-frequency amplifier circuit intermediate frequency discontinuous wave signal the high-frequency amplifier circuit that is linked in sequence between it comprises, frequency converter, intermediate frequency amplifier circuit.

Above-mentioned said signal processing and demodulator circuit are that existing ratio detector or slope discriminator constitute; Its ratio detector is made of intermediate frequency transformer B1, B2, detector diode D1～D2, resistance R 1～R7, capacitor C 1～C8; The intermediate frequency amplifying signal of above-mentioned intermediate frequency amplifier circuit output meets this frequency discriminator input P1, and the signal end P1 ' of this frequency discriminator output connects the low-frequency amplifier circuit input.

When the duty cycle pulse square wave is interfered, behind the waveform metamorphopsic distortion of square wave, can revert to square wave by shaping circuit in communication process.

Therefore second kind of signal processing and demodulator circuit are to have additional shaping circuit on first kind basis, and its shaping circuit constitutes (seeing Fig. 3) by triode VT1, VT2, VT3, resistance R 8～R15, capacitor C 9; Or constitute (seeing Fig. 4) by amplifying triode VT4, NAND gate F1～F2, resistance R 31～R36, the duty ratio audio signal of aforementioned proportion frequency discriminator output connects the input P1 ' end of shaping circuit, through shaping output duty cycle audio signal end P2, connect the input of low-frequency amplifier circuit; Or other plants base stage P1 ' the termination ratio detector output P1 ' of the triode VT4 in the shaping circuit, the input of its output P2 termination low-frequency amplifier circuit.

The signal processing of the 3rd clock and conciliation circuit are envelope detector and shaping circuit, this envelope detector, it is made of diode D21, resistance R 21～R22 capacitor C 22～C24: the frequency-selecting of intermediate frequency circuit of intermediate frequency amplifying signal end P21 through forming by L1 and C21 of intermediate frequency amplifier circuit output, the intermediate-freuqncy signal of selecting enters envelope detector by inductance L 22, duty ratio audio signal after the detection is given by triode VT4 base stage, resistance R 31～R35 and capacitor C 31 built-up circuits and is carried out processing and amplifying, obtains the duty ratio audio signal again after the shaping circuit shaping; Signal P1 ' the end of its detection output is connected with the input P1 ' end of shaping circuit, and the duty ratio audio signal P2 of the fidelity of exporting through its shaping circuit is connected with the low-frequency amplifier circuit input.

In order to demodulate audio signal, connect the secondary demodulation circuit in above-mentioned various signal processing with after reconciling circuit outward, secondary demodulation circuit and low-frequency amplifier circuit connect.Said secondary demodulation circuit is by diode D3 and form filter circuit by capacitor C32～C34, resistance R 37, potentiometer W and constitute.When the duty ratio audio signal by diode D3 unidirectional conducting becoming dc pulse signal after filter circuit filtering, promptly obtain required audio signal.

Do not add secondary demodulation circuit people in addition and can realize hearing normal sound yet, because the normal sound frequency that people can hear is 16HZ～20KHZ interval range, it when exceeding 20KHZ ultrasonic wave, people's ear be can't hear, and the duty ratio audio signal of 35KHZ～36KHZ, contain the sound of ultrasonic wave and audio frequency by the loud speaker output packet, wherein ultrasonic wave sound people ear be can't hear, and can only hear the sound of normal audio.Therefore, the duty ratio audio signal can directly be sent into low-frequency amplifier circuit and amplify, again through the loud speaker output sound.

This wireless operation principle characteristic:

Said high frequency discontinuous wave is compared with amplitude-modulated wave and frequency-modulated wave and had characteristic: the first, discontinuous wave is compared with amplitude-modulated wave, and its amplitude does not change when high frequency waves are launched, and all is conforming persistent wave.When high frequency waves stopped to launch, the range value of high-frequency signal ripple became 0.It has changes in amplitude from this angle.And changes in amplitude is very big, is to grow out of nothing, from having to nothing.So envelope detector can demodulation it; The second, the high frequency discontinuous wave is compared with frequency-modulated wave, and it is as frequency-modulated wave, the variation that does not stop in certain frequency range of radio wave frequency.The interrupted wave frequency of high frequency is constant, and these are different with frequency-modulated wave.When the high frequency discontinuous wave was disconnected, its frequency became 0 again.Can find out that high frequency waves have frequency change again, and frequency change is very big, is to grow out of nothing, from having to nothing.So ratio detector also can demodulation it.Above characteristic can be found out: the envelope detector of amplitude modulation or the frequency discriminator of frequency modulation can both this high frequency discontinuous waves of demodulation.

Claims

1, a kind of late model radio, the high-frequency amplifier circuit that is linked in sequence between it comprises, frequency converter, intermediate frequency amplifier circuit, signal processing and conciliation circuit, the connected loud speaker of low-frequency amplifier circuit is characterized in that: signal processing that is connected between described intermediate frequency amplifier circuit and the low-frequency amplifier circuit and demodulator circuit are the demodulator circuit of the high frequency discontinuous wave signal that is loaded with audio frequency that can receive, handle the transmitter emission.

2, a kind of late model radio according to claim 1 is characterized in that: above-mentioned said signal processing and demodulator circuit are ratio detector or slope discriminator.

3, a kind of late model radio according to claim 2, it is characterized in that: signal processing and conciliation circuit also have additional shaping circuit, the duty ratio audio signal of its aforementioned proportion frequency discriminator or slope discriminator output connects the input (P1 ') of shaping circuit, and its duty ratio audio signal end of exporting after shaping (P2) connects the input of low-frequency amplifier circuit.

4, a kind of late model radio according to claim 1, it is characterized in that: signal processing and conciliation circuit are envelope detector and shaping circuit, the input (P1) of the intermediate frequency amplifying signal termination envelope detector of its above-mentioned intermediate frequency amplifier circuit output, the input of the signal end of its detection output (P1 ') and shaping circuit (P1 ') be connected, be connected with the input of low-frequency amplifier circuit through its shaping circuit output duty cycle audio signal end (P2).

5, according to claim 2,3 or 4 described a kind of late model radios, it is characterized in that: between low-frequency amplifier circuit and signal processing and demodulator circuit, be provided with the secondary demodulation circuit, its signal processing and demodulator circuit output duty cycle audio signal end (P2) connect the secondary demodulation circuit input end, connect the input of low-frequency amplifier circuit through the audio signal end (P3) of demodulation output.