FM TRANSMITTERS: APPLICATIONS, ADVANTAGES AND DISADVANTAGES
Frequency modulation or better referred to as FM is a term often used in our day-to-day lives. FM is widely employed in radio broadcasting and communications. The technique behind frequency modulation may look complicated but simply put, it’s the process of encoding information on a particular signal – be it analogue or digital, by varying the carrier wave frequency according to the frequency of the modulating signal. The modulation signal in this case would be any information or message that has to be transmitted after being converted into an electronic signal.
An FM transmitter consists of several working pieces that work together to transmit information. While the components may seem complex to any layman, the mechanism is quite simple. FM transmitters are used in a variety of applications depending on the category; personal or commercial. Personal FM broadcasting can be found in homes as seen in electronic devices, sound systems, wireless internet routers or in schools as electrical or science projects. These types of transmitters are direct and less powerful. A personal FM transmitter can allow a phone to broadcast music stored in its memory on FM frequencies. When it comes to the professional ones, they are used for high-quality broadcast transmissions such as TV and radio stations.
Radio broadcasting requires a myriad of equipment to say the least. The microphone picks up on the voice, the audio processor refines the sound while the mixer allows one to control the various tones and aspects of the sound but out of all the bits and pieces, there is no piece more essential than the FM transmitter. Take for instance some examples of FM transmitters by Teko Broadcast, they are responsible for taking the sound from the studio, broadcast it through an antenna to the intended receivers within the listening area. Below is a highlight of some advantages and disadvantages of an FM transmitter;
PROS OF AN FM TRANSMITTER
- NOISE CANCELATION
An FM transmitter has the resilience to signal level variations because the modulation is carried as variations in frequency hence doesn’t affect the audio output. This cancels any noise or interference making it ideal for mobile radio applications and other portable applications. Noise is a form of amplitude variation and an FM receiver will reject such noise signals. The noise in FM can be further reduced by increasing the deviation.
- EASY TO APPLY MODULATION
With transmitters, it’s possible to apply modulation to a low power stage of the transmitter. It’s not necessary to use a linear form of application to increase the power level to its final value.
- USE OF NON-LINEAR RF AMPLIFIERS
FM transmitters can use non-linear RF amplifiers to amp the FM signals which is more efficient than the linear ones required for signals with any amplitude variations (AM). This makes FM more viable for portable two-way radio applications.
CONS OF AN FM TRANSMITTER
- COST IMPLICATIONS
FM transmitting and receiving equipment tends to be more complex. The design of the FM transmitter and receiver is relatively complex for the modulation and demodulation purpose. This demodulator is a little more complicated hence expensive than the regular simple diode detectors used in AM.
- SMALL RECEIVING AREA
FM transmitters require a much wider channel as the receiving area of FM signal is small. This, therefore, forces the antennas for FM systems to be kept close for better communication.
- POORER SPECTRAL EFFICIENCY
FM transmitters are highly efficient and most of the power goes waste in the transmitted carrier. Additionally, the reception is limited to the line of sight making the reception area very small.