Making long-range wireless microphone attached panel diagram

Above video signal transmission for demonstration, far greater than the actual distance from the video, local prevail. Foreword Wireless microphone want to have good results, use a good power, antenna, means, in the best condition and debugging circuits. Some models site wireless microphone (the component package) will have greater distances and higher performance, complete with some practical value. If you need more longer distances (greater than 500 meters) and higher performance, first to the radio management application, we recommend that you design yourself or others or entrust site design. Enhanced wireless microphone, FM radio work, good sound quality, you can listen to ordinary radio. The microphone voice signal into electrical signals, first retransmission by a modulation stage audio voltage amplifier, which can pick up a faint voice farther and more. Modulated high frequency signal and then by an oscillating tuned antenna transmission power amplification before transmission, and transmit farther reduce the effects of hand touch the antenna oscillating stage to reduce the harmonics. This circuit is installed in accordance with the frequency in about 83MHz, simply turn coil L from the poke point, so that the oscillation frequency of 88MHz-108MHz can work, can be used with any FM radio receives the frequency signal, and restore the sound signal from the high frequency signal. Also with an external audio jack and a variable resistance adjusting an amount of attenuation of the input audio signal. Performance parameters: Frequency range: 80MHz-103MHz (a circuit diagram according to the parameters, adjust only the coil turns away) Operating voltage: 1.5V -9V transmit radius: more than 100 m test conditions: voltage 4.5V, ordinary radio receiver, a wireless microphone is 50cm long antenna the thin wire test sites: high residential buildings Wireless transmitter development potential: The following is a partial function or use of the wireless microphone can be achieved. For the purpose of this site to learn techniques of everyone, so do not consider the practical value of the product and other factors. 1, wireless microphone: user singing, can be free to rotate 360 ​​degrees and moves, the wire will not stumble or when performing speech, Che Houtui. 2, radio: teacher be broadcast live lectures, many students can receive radio lectures called, greatly increased the number of lectures. 3, selling wireless devices: when to sell goods on the street, selling wireless microphone with a certain novelty, will receive more than ordinary microphone good advertising effect. 4, radio listener: a better concealment and security, can listen to the radio with a headset in the distance, do not worry about embarrassing scene meet. 5, wireless alarm devices hold: unattended certain distance. For example, can monitor the sound floor door of the second floor, it acts as a burglar alarm. 6, wireless electronic doorbell: since radio propagation sound, and therefore may be radio propagation doorbell sound, may also be converted into pairing radios. 7, wireless electronic musical instruments: the harmonica, erhu, guitar and other instruments sound receiving radio broadcast or use an amplifier to expand, can better enjoy the music. 8, the electronic hearing aid: by adjusting the volume of the radio or microphone, then amplifies the sound with the headphones can effectively improve the elderly hearing. 9, small voice lights: the output of the power amplifier connected to a speaker change corresponding wattage 6V, 12V automotive bulb, adjust the volume place. 10, reading memory booster: hearing aids and similar to the microphone at yourself, listen to your own voice reading to exclude outside interference, from the focus effect. 11, small radio stations: suitable for schools, factories and other units have organized various programs on their own, can play music, news, notices, etc., by listening to the radio. 12, television sound transponders: Listen can not influence others sleep with headphones while watching TV, but by the headphone cord length control. This device may not be limited. Referring to FIG circuit working principle MIC nature first audio signal into an audio electrical signals, C2 is coupled to the base of Q modulated, when a voice signal, the transistor junction capacitance will change the oscillation frequency is changed → complete frequency modulation, FM i.e. . C8 then coupled via a high frequency tuning amplifier for amplifying the modulated high frequency signal, and then through C12, L3 and TX antennas transmit high frequency electromagnetic waves with a frequency change of the sound signal changes outward. Wherein R1 is a bias resistor microphone MIC, generally selected in the 2K-5.6K. Collector resistor R4. R5 is the base resistance, bias current to Q1. R6 is an emitter resistor, the stabilizing effect of the DC operating point Q1; Q2, R7, R8, C4, C5, L1, C6, C7 frequency oscillating circuit composition, R7 to provide bias Q2 base, C5 and L1 tank, value can be changed to change its transmission frequency, C4 is the feedback capacitor, R8 Q2 DC operating point stabilizing effect, C7 blocking flow of AC capacitors; Q3, R9, R10, L2, C10, C11 composed of a high-frequency power amplifier circuit. R9 power transistor Q3 to base current, C10 and L2 tuning circuit amplification, and tuning the resonant circuit L1 and C5 maximum output power at the same frequency, firing distances. We designed FM radio transmission frequency band can be used with any FM radio receives the frequency signal, and restore the high frequency signal from the sound signal, thereby completing a variety of purposes. PCB board in FIG. Assembly instructions: 1, the resistance of ceramic capacitors do not have positive and negative points, but must pay attention to the resistance and capacitance values ​​no mistake. See the relevant methods of electronic experiment kit Lianyungang electronic network in this article. 2, the microphone board are positive and negative points, and an aluminum electrode is an anode connected to the housing, and the other is a cathode. For ease of installation, please add two welding pins. 3, transistor three pin function is completely different, have to make clear. See recognition of electronic experiment kit Lianyungang electronic network of related electronic information provided. 4, the package member made of copper wire coil, outside of it a layer of insulating varnish. It is a key component that adjusts the coil spacing to change the transmit frequency and distance. L1 turns from near and exchange capacity becomes larger capacitance makes the transmission frequency becomes lower; To transmit frequency becomes higher, it is necessary to take measures contrary. L1 and parallel capacitance variation range not too large or small, or the transmission frequency will be biased to the mark. Even high-frequency transmission signal is not generated (not oscillate). 5, the circuit board containing the component package pins, mounted in the key points, and an electronic test kits can be used in conjunction with a flexible, can be made wider range of electronic experiments. 6, the elements do not install the wrong position, the welding time is preferably controlled at 2-3 seconds and placed in place strive aesthetic element, to repeatedly check, after debugging power use. Packed finished board Hands-on production All Group photo elements: Mount resistor and ceramic capacitors Installation triode Mount Inductor, pay attention to 4.5T and 5.5T, inductance is not the same number of turns. Mounting the electrolytic capacitor, the positive and negative attention. Installation potentiometer, the potentiometer is used to adjust the sound size. Add pins to the microphone. MIC Installation Mounting pin, one end of the antenna, 2 is a power supply terminal, 3 is a signal input terminal. Mounted antenna The basic circuit is installed ~! Commissioning Description: Go first to FM radio (record) sound machine, turn on the power and the volume will be around 100MHz frequency modulation radio-free place. Wireless microphone to the circuit board through the power, a radio aligned, the oscillation coil L1 is adjusted sparsely (distance between the coils) with a screwdriver (non-inductive conditions, please screwdriver, see the website or self), until the outgoing radio screams . In this case the microphone and then slowly moved away from the radio while appropriately adjusting the volume of the radio (or microphone plate), the tuning knob until the clearest sound, and the farthest distance up. In the above-described steps are recommended 88MHz, 98MHz, 108MHz are near to try, so even if there is a large frequency deviation wireless microphone transmitter, the radio can be received. If the radio can not receive it, please check the elements have not installed wrong, there is no damage components, power supply is normal. Selection of higher sensitivity, more selective high-grade radio can receive greater distances

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