CN102158776A - Frequency-modulation wireless microphone made of single battery - Google Patents
Frequency-modulation wireless microphone made of single battery Download PDFInfo
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- CN102158776A CN102158776A CN2011101098624A CN201110109862A CN102158776A CN 102158776 A CN102158776 A CN 102158776A CN 2011101098624 A CN2011101098624 A CN 2011101098624A CN 201110109862 A CN201110109862 A CN 201110109862A CN 102158776 A CN102158776 A CN 102158776A
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Abstract
The invention relates to a frequency-modulation wireless microphone made of a single battery. The frequency-modulation wireless microphone comprises a direct current power supply DC, a power supply filter circuit, an audio frequency signal input circuit and a high frequency oscillation and transmission circuit, and is characterized in that the high frequency oscillation and transmission circuit comprises a bias circuit of a NPN transistor VT1 and an audio frequency signal input circuit. The frequency-modulation wireless microphone adopts a single NPN transistor and the single battery, and changes the frequency of a high frequency oscillator by changing the junction capacitance between b and c of the NPN transistor in a high frequency oscillation circuit, thereby modulating oscillation frequency into frequency-modulated wave. As the circuit only adopts one NPN transistor, oscillation circuit frequency is more stable and suitable for the signal transmission with higher fidelity requirement, such as television wireless headphones and the like. Test proves that the frequency-modulation wireless microphone only utilizes eight common discrete components and realizes the purposes that the circuit structure of the frequency-modulation wireless microphone is simple, the oscillation frequency is stable, frequency shift is not easy to occur, the manufacture cost is low, power consumption is low, the frequency-modulation wireless microphone is easy for popularization, and the like.
Description
Technical field
The invention belongs to electronic technology and communication technique field, relate to the frequency modulation wireless microphone that a kind of single battery is made.
Background technology
Common frequency modulation wireless microphone is that the junction capacitance between the transistor b-c changes the modulating frequency that changes high-frequency generator in the high-frequency oscillating circuits by changing, thereby realize that modulation becomes frequency-modulated wave to frequency of oscillation, amplify by the high frequency selective frequency amplifier circuit, at last by transmitting antenna to space radiation, this is the typical operation principles of most frequency modulation wireless microphones.
The present invention adopts single NPN transistor, single battery, and the junction capacitance between transistor b-c changes the frequency that changes high-frequency generator in the high-frequency oscillating circuits by changing, thereby the frequency of oscillation modulation is become frequency-modulated wave.Because of circuit only uses a NPN transistor, be subjected to involving and disturbing less of circuit front and back level, make that the frequency of oscillating circuit is more stable, be well suited for being used for the signal transmission that fidelity such as tv wireless earphone is had relatively high expectations, can be widely used in fields such as classroom instruction.Evidence: the present invention only uses 8 common discrete components, has realized that frequency modulation wireless microphone circuit structure is simple, the stable difficult purposes such as easy, with low cost and little power consumption of running frequently, make of frequency of oscillation.
Below describe the correlation technique content that frequency modulation wireless microphone that this single battery makes relates in detail in manufacturing process.
Summary of the invention
Goal of the invention and beneficial effect: the present invention adopts single NPN transistor, single battery, the junction capacitance between the NPN transistor b-c changes the frequency that changes high-frequency generator in the high-frequency oscillating circuits by changing, thereby modulation becomes frequency-modulated wave to frequency of oscillation.Because of circuit only uses a NPN transistor, make the circuit oscillation frequency more stable, be well suited for being used for the signal transmission that fidelity such as tv wireless earphone is had relatively high expectations.Evidence: the present invention only uses 8 common discrete components, has realized that frequency modulation wireless microphone circuit structure is simple, frequency of oscillation stablely is difficult for running frequently, make easy, with low cost and little power consumption, purpose such as be easy to popularize.
Technical characterictic: the frequency modulation wireless microphone that single battery is made, be made up of DC power supply DC, electric source filter circuit, audio signal input circuit, the higher-order of oscillation and radiating circuit, it is characterized in that: the higher-order of oscillation and radiating circuit comprise biasing circuit and the audio signal input circuit of NPN transistor VT1.
Annexation in the composition of circuit and the circuit between the components and parts
The connection features of the biasing circuit of NPN transistor VT1 and audio signal input circuit is: the base stage of a termination NPN transistor VT1 of the output D of Electret condenser microphone MIC and resistance R 1, the anodal VCC of the other end connection circuit of resistance R 1, the metal shell end S of Electret condenser microphone MIC links to each other with circuit ground GND.
The base stage of the higher-order of oscillation and radiating circuit: NPN transistor VT1 is with connecing an end of capacitor C 1 and the end of higher-order of oscillation coil L1, the other end of the other end of capacitor C 1 and higher-order of oscillation coil L1 links to each other with the collector electrode of NPN transistor VT1, the end of transmitting antenna T, the emitter connection circuit ground GND of NPN transistor VT1.
The connection features of DC power supply DC and electric source filter circuit is: an end of capacitor C 2 and the positive pole of electrochemical capacitor C3 connect the end of mains switch K1, the positive pole of another termination DC power supply DC of mains switch K1, the negative pole connection circuit ground GND of the other end of capacitor C 2 and electrochemical capacitor C3, the negative pole connection circuit ground GND of DC power supply DC.
The circuit working principle: the frequency modulation wireless microphone that single battery is made changes voice signal into tone currents by Electret condenser microphone MIC, the high-frequency generator of being made up of NPN transistor VT1, higher-order of oscillation coil L1 and capacitor C 1 forms FM signal and is radiated the space by transmitting antenna T again.In distance frequency modulation wireless microphone 10m scope, the broadcast receiver reception by frequency modulation(FM) broadcast band (FM wave band) is reduced into sound through loud speaker, realizes the radio transmission of sound.
Description of drawings
Accompanying drawing is the embodiment circuit working schematic diagram that the invention provides the frequency modulation wireless microphone of a single battery making; For reducing the interference of electromagnetic signal, require to use the Electret condenser microphone of two ends output type, the metal shell end S connection circuit ground GND of Electret condenser microphone MIC to Electret condenser microphone MIC.
Embodiment
The circuit working schematic diagram and the description of drawings of the frequency modulation wireless microphone of making according to single battery shown in the accompanying drawing, and implement to realize the present invention according to the described components and parts specification requirement of embodiment.
The selection of components and parts and technical parameter thereof
MIC is an Electret condenser microphone, and Electret condenser microphone MIC should select the microphone of two ends output type for use, and its drain D is an audio signal output end, connection circuit ground GND after the metal shell end of Electret condenser microphone links to each other with source S.It is output that field effect transistor is connected into drain D, helps improving the voltage gain of output signal, and the sensitivity of Electret condenser microphone is increased.Require the shell ends S connection circuit ground GND of Electret condenser microphone MIC, to improve the anti-interference of circuit.
Electret condenser microphone sensitivity is high more, and the effect of wireless microphone is good more.Electret condenser microphone MIC can select for use the CM-18W type (the higher Electret condenser microphone of sensitivity of Ф 10mm * 6.5mm), its sensitivity is divided into five retainings, represents with color dot respectively: redly be-66dB, Xiao Huang is-62dB, rheum officinale is-58dB, Lan Sewei-54dB, and white is greater than-52dB; Present embodiment is selected the product of white point for use;
VT1 is a NPN transistor, selects power transistor among the NPN type 2SC9018 for use, requires β 〉=110;
It is 1/8W metalfilmresistor or fixed carbon resister that resistance is selected power for use, and the resistance of resistance R 1 is 1K Ω;
C1 is a ceramic disc capacitor, and capacity is 10PF; C2 is an electric capacity of the dacron, and capacity is 0.01 μ F; C3 is an electrochemical capacitor, and capacity is 220 μ F/10V;
K1 is a mains switch; L1 is a higher-order of oscillation coil.
The making of circuit and subelement
The making of higher-order of oscillation coil L1: flat around 10 circles on the ballpoint pen core of ￠ 3.5mm with the enamelled wire of ￠ 0.5mm, extract the ballpoint pen core then out and form air-core inductance, scrape off behind the coat of paint at inductance coil two ends zinc-plated with pocket knife;
T is a transmitting antenna, and the telescopic antenna that available 60cm is above also can use 90cm multiply plastics flexible cord as transmitting antenna, and an end is welded on the printed circuit board (PCB), and the other end is stretched out naturally.
The debugging of circuit
The printed circuit board (PCB) correspondence position is inserted in the zinc-plated back of each component pin, and each component pin should stay short as far as possible.Can not make higher-order of oscillation coil L1 distortion when noting the welding coil.
Check printed circuit board (PCB) and welding situation earlier, should not have short circuit and empty, dry joint phenomenon, can connect DC power supply then.With the universal instrument shelves of direct voltage measure between the base stage of transistor VT1 and the emitter voltage should＞0.7V, with higher-order of oscillation coil L1 two terminal shortcircuits once, voltage should have certain variation, this explanation circuit vibrates.
Open FM receiver, pull out the antenna of FM receiver, band switch should place the FM wave band, with the close FM receiver of the transmitting antenna of frequency modulation wireless microphone.Slowly rotate the FM receiver tuning knob then, simultaneously to Electret condenser microphone MIC speech, be tuned to FM receiver receive till the voice signal sound.If FM receiver can not receive the signal of frequency modulation wireless microphone emission in tuning range, can stretch or compress higher-order of oscillation coil L1 gently, change the width of enamelled wire coil, careful again tuning modulation broadcast receiver is until receiving voice signal clearly.
Then draw back the distance between wireless microphone and the FM receiver gradually, up to distance when reaching 9～10m, still can receive clearly till the voice signal.Attention wireless microphone tranmitting frequency in debugging should be avoided the frequency in the broadcasting station in the local fm band.
No. 5 batteries of 1 joint are as power supply, and the operating current of frequency modulation wireless microphone is about 19mA.Select for use the high-quality alkaline battery about 400mAh of every joint capacity (MAH) to be example, but No. 5 battery running hours of 1 joint were about 40 hours.In actual use, the different times that continue to use of kind because of battery have discrepancy.
Claims (4)
1. the frequency modulation wireless microphone made of a single battery, be made up of DC power supply DC, electric source filter circuit, audio signal input circuit, the higher-order of oscillation and radiating circuit, it is characterized in that: the higher-order of oscillation and radiating circuit comprise biasing circuit and the audio signal input circuit of NPN transistor VT1.
2. the frequency modulation wireless microphone that single battery according to claim 1 is made, the connection features of the biasing circuit of NPN transistor VT1 and audio signal input circuit is: the base stage of a termination NPN transistor VT1 of the output D of Electret condenser microphone MIC and resistance R 1, the anodal VCC of the other end connection circuit of resistance R 1, the metal shell end S of Electret condenser microphone MIC links to each other with circuit ground GND.
3. the frequency modulation wireless microphone that single battery according to claim 1 is made, the connection features of the higher-order of oscillation and radiating circuit is: the base stage of NPN transistor VT1 is with connecing an end of capacitor C 1 and the end of higher-order of oscillation coil L1, the other end of the other end of capacitor C 1 and higher-order of oscillation coil L1 links to each other with the collector electrode of NPN transistor VT1, the end of transmitting antenna T, the emitter connection circuit ground GND of NPN transistor VT1.
4. the frequency modulation wireless microphone that single battery according to claim 1 is made, the connection features of DC power supply DC and electric source filter circuit is: an end of capacitor C 2 and the positive pole of electrochemical capacitor C3 connect the end of mains switch K1, the positive pole of another termination DC power supply DC of mains switch K1, the negative pole connection circuit ground GND of the other end of capacitor C 2 and electrochemical capacitor C3, the negative pole connection circuit ground GND of DC power supply DC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101098624A CN102158776A (en) | 2011-04-28 | 2011-04-28 | Frequency-modulation wireless microphone made of single battery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101098624A CN102158776A (en) | 2011-04-28 | 2011-04-28 | Frequency-modulation wireless microphone made of single battery |
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| CN102158776A true CN102158776A (en) | 2011-08-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011101098624A Pending CN102158776A (en) | 2011-04-28 | 2011-04-28 | Frequency-modulation wireless microphone made of single battery |
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Cited By (3)
| 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 |
| CN104301841A (en) * | 2014-09-29 | 2015-01-21 | 成都英博联宇科技有限公司 | Simple wireless microphone circuit |
| CN104682874A (en) * | 2015-03-18 | 2015-06-03 | 王志 | Micropower frequency modulation repeater without power supply |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2049053U (en) * | 1988-12-21 | 1989-12-06 | 顾东 | Hosehold multipurpose device |
| CN2189748Y (en) * | 1994-04-30 | 1995-02-15 | 田海珠 | Multi-function electroscope |
| CN201957211U (en) * | 2011-04-28 | 2011-08-31 | 陈子杨 | FM wireless microphone made of single battery |
-
2011
- 2011-04-28 CN CN2011101098624A patent/CN102158776A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2049053U (en) * | 1988-12-21 | 1989-12-06 | 顾东 | Hosehold multipurpose device |
| CN2189748Y (en) * | 1994-04-30 | 1995-02-15 | 田海珠 | Multi-function electroscope |
| CN201957211U (en) * | 2011-04-28 | 2011-08-31 | 陈子杨 | FM wireless microphone made of single battery |
Cited By (3)
| 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 |
| CN104301841A (en) * | 2014-09-29 | 2015-01-21 | 成都英博联宇科技有限公司 | Simple wireless microphone circuit |
| CN104682874A (en) * | 2015-03-18 | 2015-06-03 | 王志 | Micropower frequency modulation repeater without power supply |
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Application publication date: 20110817 |