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FM Transmitter Circuits

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In a frequency modulation (FM) transmitter, it is added by varying the radio signal's frequency slightly. Many other types of modulation are used.

In an FM (frequency modulation) transmitter the frequency of the carrier is varied by the audio signal. Angle modulation is the proper term for modulation by changing the instantaneous frequency or phase of the carrier signal. FM transmitters can be stereo as well and using a PLL tunning circuit you can achive a stable audio transmition on FM band.
 
True FM and phase modulation are the most commonly employed forms of analogue angle modulation. Direct FM (true Frequency modulation) is where the frequency of an oscillator is altered to impose the modulation upon the carrier wave. This can be done by using a voltage-controlled capacitor (Varicap diode) in a crystal-controlled oscillator or frequency synthesiser.
The frequency of the oscillator is then multiplied up using a frequency multiplier stage, or is translated upwards using a mixing stage, to the output frequency of the transmitter.
 
 In some indirect FM solid state circuits, an RF drive is applied to the base of a transistor. The tank circuit (LC), connected to the collector via a capacitor, contains a pair of varicap diodes. As the voltage applied to the varicaps is changed, the phase shift of the output will change.
 

Circuits




This is a simple wireless FM transmitter circuit which uses RF communication to transmit the medium or low power FM signal. Its maximum range is 2 km.

FM Transmitter Circuit Diagram. 1. Newer Older. Thanks to Brett ... jonlesser's photostream (732) · Megapolis FM Transmitter Workshop; Megapolis Atari Punk Console Workshop; FM Transmitter Circuit ...

Most of you guys send emails to Free circuit diagrams 4u asking Fm transmitters so today we are going to give you a simple transmitter circuit diagram.The special thing of this circuit is we can us...

In this article, I am going to show how to plan and make a single transistor FM transmitter on a stripboard (prototype board). This project has been tested in a 5 storey building and it works perfe...

The circuit itself is a slight variation on Kogawa's simplest FM transmitter design, and the method of building it is sometimes referred to as Manhattan style. It uses a piece of copper-clad circui...


Weekend Projects - Super Simple FM Transmitter


How to build a SPY Bug


Build your own small pirate radio station.I show you how to build a simple FM...


A Breadboard FM Transmitter Bug