FM Transmitters: How They Work, Types, Applications

The FM transmitter is an electronic circuit or device used for audio broadcasting in short distance or long distance about Kilometers or miles. The basic principle of the FM transmitter is modulating the audio signals in the form of electrical signals such as radio waves. 

This frequency of waves is transmitted from the FM transmitter to the FM receivers. This frequency is 87.5 to 108.0 MHz. This frequency may vary depending on the region you are living in. IF the transmitted frequency is 90.4MHz  means those who have set the frequency in the Radio receiver can receive the signals from the transmitter.

The FM transmitter is commonly used in Radio broadcasting but in many electronic devices the radio signal transmitters are used for controlling electronic devices also. For example the kids toy car is controlled by a wireless radio controller circuit. The major walkies talkies are also working based on the same Radio frequency technology.

Another use of radio FM transmitters is used in wireless mic, with a portable FM transmitter and a FM receiver, one can easily setup a wireless microphone system for a small event or party.

Usage of the FM transmitters comes in strict regulations. This is depending on the country and location. In the United States, the “Federal Communications Commission” regulating the usage of FM transmitters and Ham radio. If you are Using a transmitter that does not comply with FCC regulations, it can result to fines or other penalties.
The FM transmitters come in a different output signal power. which is represented in watts. The high power transmitter circuit has the greater range of the signal transmitting power.

Also Check: You can check how i build a simple transistor radio circuit using two transistor .

Working

An FM transmitter works by modulating an audio signal onto a specific frequency, known as the carrier frequency. The modulated signal, or the modulation, is then broadcasted over a short distance, which can be picked up by a receiver tuned to the same frequency.

The audio signal is converted into an electrical current, and this current is used to vary the amplitude of the carrier frequency. This process is called as amplitude modulation, or AM. In FM transmitters, instead of modulating the amplitude of the carrier frequency, the audio signal is used to modulate the frequency of the carrier signal. This process is known as frequency modulation, or FM.

The modulated signal is then amplified and transmitted via an antenna. The receiver, which is tuned to the same frequency as the transmitter, receives the signal and demodulates it to extract the original audio signal. The recovered audio signal can then be played through speakers or headphones.

Application

1. In-car audio systems.
2. Home audio systems.
3. Wireless microphones.
4. Wireless communication systems.
5. Broadcasting.
6. Advertising.
7. Emergency broadcasting.