CN102158792A - Frequency modulation radio microphone - Google Patents
Frequency modulation radio microphone Download PDFInfo
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- CN102158792A CN102158792A CN2011100097855A CN201110009785A CN102158792A CN 102158792 A CN102158792 A CN 102158792A CN 2011100097855 A CN2011100097855 A CN 2011100097855A CN 201110009785 A CN201110009785 A CN 201110009785A CN 102158792 A CN102158792 A CN 102158792A
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Abstract
The invention belongs to the field of electronic technical application and relates to a frequency modulation radio microphone, which comprises a direct current power supply (DC), a high frequency filter circuit, an audio signal input circuit, an oscillating circuit, a radio frequency power amplification circuit and an emitting antenna (T), wherein the oscillating circuit is a capacitance three-point type oscillator. The improved capacitance three-point type oscillator is used in the frequency modulation radio microphone and the junction capacitances of transistors b-e are changed following the change of an audio voltage, so as to change an oscillation frequency, thereby realizing the oscillation frequency modulation. Such an oscillator has stable oscillation frequency and is fit for the signal transmission high in fidelity such as television wireless earphone. A test proves that the simple structure of the frequency modulation radio microphone is realized by the using of common discrete components, such an improved capacitance three-point type oscillator is easily manufactured, the manufacturing cost is low, the oscillation frequency is stable, the emitting distance is far and the power consumption is less.
Description
Technical field
The invention belongs to the application of electronic technology field, relate to a kind of frequency modulation wireless microphone.
Background technology
At present, common frequency modulation wireless microphone is that the junction capacitance between transistorized c-b changes the output frequency that changes high-frequency generator in the high-frequency oscillating circuits by changing, thereby realize the frequency-modulated wave that is modulated into to frequency of oscillation, by high frequency frequency selection circuit and amplifying circuit, at last by antenna to external radiation, these are the general operation principles of most frequency modulation wireless microphones.
The present invention tries out the modified model capacitance connecting three point type oscillator, and the variation by audio voltage changes the junction capacitance between transistor b-e, thereby makes changing of frequency of oscillation, realizes the frequency of oscillation modulation.It is stable that this oscillator has frequency of oscillation, is well suited for being used for the signal transmission that fidelitys such as tv wireless earphone, stage performance are had relatively high expectations.Evidence: the present invention all uses common discrete component to realize that frequency modulation wireless microphone circuit structure simply waits specification requirement.This follow-on capacitance connecting three point type oscillator is made easily, cost of manufacture is cheap, and the multiple advantage of the far away and little power consumption of oscillatory work frequency stabilization, transmitting range is arranged.
Below describe this frequency modulation wireless microphone in detail and make the correlation technique that relates to.
Summary of the invention
Goal of the invention and beneficial effect: the present invention tries out the modified model capacitance connecting three point type oscillator, and the variation by audio voltage changes junction capacitance between transistorized b-e, thereby makes changing of frequency of oscillation, realizes the frequency of oscillation modulation.It is more stable that this oscillator has frequency of oscillation, and very occasion is used for the signal transmission of having relatively high expectations of fidelitys such as tv wireless earphone.Evidence: the present invention all uses common discrete component to realize that frequency modulation wireless microphone circuit structure is simple, this follow-on capacitance connecting three point type oscillator is made easily, cost of manufacture is cheap, and the multiple advantage of the far away and little power consumption of oscillatory work frequency stabilization, transmitting range is arranged.
Technical characterictic: frequency modulation wireless microphone, by DC power supply (DC), high-frequency filter circuit, the audio signal input circuit, oscillating circuit, rf power amplifier circuit and transmitting antenna (T) are formed, it is characterized in that: oscillating circuit is the modified model capacitance connecting three point type oscillator, the end of inductance coil L1 in the modified model three-point oscillator circuit of capacitance and an end of capacitor C 1, one end of capacitor C 3 links to each other, the other end connection circuit ground (GND) of the other end of inductance coil L1 and capacitor C 1, the base stage of the other end of capacitor C 3 and NPN transistor VT1, one end of resistance R 1, one end of resistance R 2, one end of capacitor C 4 links to each other, the positive pole (VCC) of another termination DC power supply of resistance R 1, the other end connection circuit ground (GND) of resistance R 2, the emitter of NPN transistor VT1 is with the other end that connects capacitor C 4, one end of capacitor C 5, one end of capacitor C 7 and an end of resistance R 3, the other end of the other end of capacitor C 5 and resistance R 3 is with connection circuit ground (GND), and the collector electrode of NPN transistor VT1 connects the positive pole of DC power supply (VCC).
Annexation in the composition of circuit and the circuit between the components and parts
1. an end of the output termination capacitor C 2 of the electret capacitor microphone in the audio signal input circuit, the base stage of another termination NPN transistor VT1 of capacitor C 2, the shell ends connection circuit ground (GND) of electret capacitor microphone.
2. rf power amplifier circuit: NPN transistor VT2, capacitor C 7, resistance R 4, inductance coil L2, capacitor C 8, capacitor C 9 and transmitting antenna (T) are formed, it is characterized in that: the base stage of NPN transistor VT2 is with the other end that connects capacitor C 7, one end of resistance R 4, the other end of the collector electrode of NPN transistor VT2 and resistance R 4, the end of inductance coil L2, one end of capacitor C 8, one end of capacitor C 9 links to each other, the other end of the other end of inductance coil L2 and capacitor C 8 is with the positive pole (VCC) that connects DC power supply, antenna (T) is penetrated in the other end sending and receiving of capacitor C 9, the emitter connection circuit ground (GND) of NPN transistor VT2.
The circuit working principle
The circuit of frequency modulation wireless microphone mainly contains audio signal input, oscillating circuit, high frequency amplifies and radio-frequency power amplifies four parts.Inductance coil L1, capacitor C 1, capacitor C 3～C5, transistor VT1 etc. form the modified model capacitance connecting three point type oscillator, and this oscillating circuit has the advantages that to be difficult for running frequency.
The frequency of oscillator mainly by inductance coil L1 and capacitor C 1 decision, by trimming inductance coil L1, can cover 88～108MHz frequency range.The audio signal that capacitor microphone (MIC) produces is coupled to base stage at transistor VT1 through capacitor C 2, junction capacitance between the b-e of transistor VT1 causes the variation of frequency of oscillation along with the variation of input audio voltage, realization is modulated frequency of oscillation, signal after the modulation carries out radio-frequency power through transistor VT2 again and amplifies, at last by antenna to external radiation.
Description of drawings
1. the accompanying drawing frequency modulation wireless microphone circuit working schematic diagram that is.
2. the MIC in the accompanying drawing is the Electret condenser microphone of two contacts, the housing connection circuit ground of microphone.
Embodiment
The components and parts specification requirement and the adjustment method of frequency modulation wireless microphone fundamental diagram shown in the drawings to specifications and description of drawings and the following stated are implemented, and can realize the present invention.
The selection of components and parts and technical parameter thereof
1.MIC be microphone, select the electret capacitor microphone of two contacts for use, require the housing connection circuit ground of capacitor microphone, with anti-interference by circuit.
2. transistor VT1～VT2 selects power transistor among the NPN type 2SC9018 for use, and β requires 〉=100.
3. all to select power for use be 1/8W metalfilmresistor or fixed carbon resister to resistance, and the resistance of resistance R 1～R3 is: 10K Ω, 5.6K Ω, 150 Ω; The resistance of resistance R 4 is 22K Ω.
4.C1, C4, C5 be ceramic disc capacitor, capacity is 10PF; The capacity 0.47 μ F of C2 electric capacity of the dacron; The capacity of C3 electric capacity is 4PF; The capacity of C6 electric capacity is 1000PF; The capacity of C7 electric capacity is 22PF; The capacity of C8 electric capacity is 20PF; The capacity of C9 electric capacity is 51PF.
5. inductance coil L1, L2 use ￠ 0.31mm enamelled wire in the circuit, single flat coiled air-core inductance on the pole of ￠ 3.5mm, and the parameter of inductance coil is respectively: L1 is flat around 10T; L2 is flat around 5T.
6.T be transmitting antenna, can use the above telescopic antenna of 60cm, also can select for use the soft line that drags of 90cm as transmitting antenna.
The circuit debugging method
The debugging of frequency modulation wireless microphone does not generally need professional electrical apparatus such as sweep generator, frequency meter, and this also is that the present invention makes characteristics of success easily.
Can finely tune frequency of oscillation by the spacing of adjusting the inductance coil L1 turn-to-turn in the circuit, by the vibration radiation of inductance coil L1, the FM receiver in frequency modulation wireless microphone 2m scope should be received the signal that microphone sends on a certain frequency.
Frequency modulation wireless microphone and FM receiver draw distance to test: the spacing of difference trimming inductance coil L2 turn-to-turn, can make the frequency of oscillation of its resonance in inductance coil L1, amplify and maximum transmitting power with picked up signal, guarantee that reliable communication distance 〉=50m is qualified.If improve the tranmitting frequency of wireless microphone, can be by increasing the spacing of inductance coil L1 coil.If the signal that FM receiver is received is more weak or communication distance is near, this explanation centre frequency does not drop in the FM broadcasting band limits, the just harmonic wave of receiving on the broadcast receiver, with noninductive bottle opener compress or loosen inductance coil L1 in the oscillating circuit, stable voice signal, the stability of observation signal and the coverage of transmission appear up to broadcast receiver.
Thermal stability test: the solder horn with electric iron directly heats transistor VT1 collector electrode in the frequency modulation wireless microphone circuit, after the heating several seconds, under the temperature of transistor VT1 reached very high situation, common FM receiver is normal received signal still, does not exist substantially and runs phenomenon frequently.
No. 7 battery serial connections of 3 joints obtain the 4.5V direct voltage, and the supply voltage of this moment makes the operating current of frequency modulation wireless microphone be about 21mA, are that 500mAh (MAH) calculates by the every joint capacity of high-quality alkaline battery, and it is 46 hours that 3 batteries running hours are about.In actual use, the different times that continue to use of kind because of battery will have greater difference.
Claims (3)
1. frequency modulation wireless microphone, by DC power supply (DC), high-frequency filter circuit, the audio signal input circuit, oscillating circuit, rf power amplifier circuit and transmitting antenna (T) are formed, it is characterized in that: oscillating circuit is the modified model capacitance connecting three point type oscillator, the end of inductance coil L1 in the modified model three-point oscillator circuit of capacitance and an end of capacitor C 1, one end of capacitor C 3 links to each other, the other end connection circuit ground (GND) of the other end of inductance coil L1 and capacitor C 1, the base stage of the other end of capacitor C 3 and first NPN transistor (VT1), one end of resistance R 1, one end of resistance R 2, one end of capacitor C 4 links to each other, another termination dc power anode (VCC) of resistance R 1, the other end connection circuit ground (GND) of resistance R 2, the emitter of first NPN transistor (VT1) is with the other end that connects capacitor C 4, one end of capacitor C 5, one end of capacitor C 7 and an end of resistance R 3, the other end of the other end of capacitor C 5 and resistance R 3 is with connection circuit ground (GND), and the collector electrode of first NPN transistor (VT1) connects dc power anode (VCC).
2. frequency modulation wireless microphone according to claim 1, it is characterized in that: an end of the output termination capacitor C 2 of the electret capacitor microphone in the audio signal input circuit, the base stage of another termination first NPN transistor (VT1) of capacitor C 2, the shell ends connection circuit ground (GND) of electret capacitor microphone.
3. frequency modulation wireless microphone according to claim 1, rf power amplifier circuit is by second NPN transistor (VT2), capacitor C 7, resistance R 4, inductance coil L2, capacitor C 8, capacitor C 9 and transmitting antenna (T) are formed, it is characterized in that: the base stage of second NPN transistor (VT2) is with the other end that connects capacitor C 7, one end of resistance R 4, the collector electrode of second NPN transistor (VT2) and the other end of resistance R 4, the end of inductance coil L2, one end of capacitor C 8, one end of capacitor C 9 links to each other, the other end of the other end of inductance coil L2 and capacitor C 8 is with the positive pole (VCC) that connects DC power supply, antenna (T) is penetrated in the other end sending and receiving of capacitor C 9, the emitter connection circuit ground (GND) of second NPN transistor (VT2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100097855A CN102158792A (en) | 2011-01-18 | 2011-01-18 | Frequency modulation radio microphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100097855A CN102158792A (en) | 2011-01-18 | 2011-01-18 | Frequency modulation radio microphone |
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| CN102158792A true CN102158792A (en) | 2011-08-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011100097855A Pending CN102158792A (en) | 2011-01-18 | 2011-01-18 | Frequency modulation radio microphone |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497607A (en) * | 2011-12-20 | 2012-06-13 | 洪珍 | Discrete component type frequency modulated wireless microphone |
| CN102572664A (en) * | 2012-02-19 | 2012-07-11 | 黄勇 | Discrete component frequency modulation wireless microphone |
| CN103427851A (en) * | 2012-05-22 | 2013-12-04 | 成都酷玩网络科技有限公司 | Multifunctional miniature frequency modulation emitter |
| CN104065392A (en) * | 2013-03-24 | 2014-09-24 | 成都龙腾中远信息技术有限公司 | Frequency modulation transmitter with high interference resistance |
| CN107623651A (en) * | 2017-06-30 | 2018-01-23 | 中国建筑第七工程局有限公司 | A kind of intelligence community |
| CN109963231A (en) * | 2019-03-23 | 2019-07-02 | 西安石油大学 | A kind of vocal music microphone audio processor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201571045U (en) * | 2009-11-30 | 2010-09-01 | 段守付 | Voice wireless transmission device |
| CN201910899U (en) * | 2011-01-18 | 2011-07-27 | 黄勇 | Frequency modulation wireless microphone |
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2011
- 2011-01-18 CN CN2011100097855A patent/CN102158792A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN201571045U (en) * | 2009-11-30 | 2010-09-01 | 段守付 | Voice wireless transmission device |
| CN201910899U (en) * | 2011-01-18 | 2011-07-27 | 黄勇 | Frequency modulation wireless microphone |
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| 许永才: "实用的远距离无线调频话筒", 《电子制作》, no. 9, 31 December 1996 (1996-12-31) * |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497607A (en) * | 2011-12-20 | 2012-06-13 | 洪珍 | Discrete component type frequency modulated wireless microphone |
| CN102572664A (en) * | 2012-02-19 | 2012-07-11 | 黄勇 | Discrete component frequency modulation wireless microphone |
| CN103427851A (en) * | 2012-05-22 | 2013-12-04 | 成都酷玩网络科技有限公司 | Multifunctional miniature frequency modulation emitter |
| CN104065392A (en) * | 2013-03-24 | 2014-09-24 | 成都龙腾中远信息技术有限公司 | Frequency modulation transmitter with high interference resistance |
| CN107623651A (en) * | 2017-06-30 | 2018-01-23 | 中国建筑第七工程局有限公司 | A kind of intelligence community |
| CN109963231A (en) * | 2019-03-23 | 2019-07-02 | 西安石油大学 | A kind of vocal music microphone audio processor |
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Application publication date: 20110817 |