Video Audio Sender

Wireless Video Audio Sender Circuit

If you want to link video and audio signals to a TV receiver, it cannot only via the AV cable, you can use an video audio sender. This wireless gadget you can buy them online at amazon, AV sender is priced around $ 75 – $ 120. This is to eliminate the limitation of cable length when using the AV cable.

Video audio sender generally consists of a modulator which modulates the video and audio at a certain frequency and then mixing this signal to be included on the carrier frequency and transmits via a small antenna. This frequency band could be on VHF or UHF channels, so you can find it on the TV channel. As a source of video and audio can be used a VCD / DVD player, CCD Camera and others.

Here is an video audio sender that uses a simple transistor circuit. Wireless video audio sender is sourced from the internet site for educational purposes. Maybe some of the hobby wanted to know how a block diagram of an audio video sender or a simple block diagram of a TV transmitter.

Wireless Video Audio Sender Circuit

This video audio sender or transmitter works on UHF channel. As in the TV transmitter systems, the audio generated by FM modulation with a frequency of 4.5-6.5 MHz and Video in AM. Audio modulation is performed immediately following the carrier frequency, and the video is inserted through Emittor of the transistor mixer.

Video Audio Sender Circuit Analysis

Q3, VC1, C13, C16 and L3 all make up a Colpitts oscillator circuit that fluctuates from 220~250MHz. You can regulate the frequency to any value within this threshold by tuning VC1 or L3. C13 modulates the signal rate. When the capacitance increases, so does the modulation. R9 and C16 bias the local oscillation. If you lower R9′s frequency to 680W the oscillator’s output level will increase.

Q2 and L2 act as a frequency doubler. C7, along with FCZ7S3R5 (IF transformer), the Q4 transistor, C14, C19 and R12 all make up the mixer. This mixer takes both audio and visual signals together and “mix” them into one and passes through RF Amplifier Q1 to transmit the signal to the antenna.

Wireless Video Audio Circuit Testing

• Turning the blue component’s trimmer on VC1 varies the frequency. When we turn the trimmer, the television’s channel has to be changed accordingly. It is easier to tune the AV Sender if you have a spectrum analyzer to help you find the correct frequencies. If the frequency is tuned to 474 MHz then this would be the equivalent of your TV’s channel 14 UHF band.
• The IF transformer is used to synchronize the audio and video frequency’s level radio. If the TV’s image is too blurry then you can adjust the IFT to fine-tune the image.
• SVR1 controls the video signal input ratio, while SVR2 controls the audio portion. You can tune these components according to your needs. Keep best tuning the signal with the quality video audio sender.

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