RF Modulator

In the world of electronics, a RF modulator plays a very important role and is very useful when it comes to interfacing modern devices with age-old television sets. This article is an eye opener on RF or radio frequency modulators.

In electronic communication, data is transmitted in the form of electric signals. Every device has a particular electrical frequency of operation, which is dependent on its function and also dependent on its connecting cables. So, when two devices are connected together and they operate at different electrical frequencies, there has to be a device which converts the electric signal from one form to the other. That is what devices like RF modulator do. They are like interpreters, translating electrical signals from one device to the other.

What is a RF Modulator?
Modulation is the superimposition of a particular electrical signal on another carrier wave signal. Simply put, modulation is the changing of one or more properties of the carrier signal according to the modulating signal.

A modulator is a device that modulates electrical signals onto another type of signal. Broadly, there are two main categories of modulation techniques: digital modulation (when modulating signal is digital) and analog modulation (when modulating signal is analog). Each type is further classified according to which, characteristic of carrier wave is modified. This includes frequency modulation (frequency of the carrier wave is varied according to amplitude of modulated signal), amplitude modulation (amplitude of carrier wave is varied according to the amplitude of the modulating signal) and many such techniques. Modern RF modulators perform digital modulation.

Applications
RF modulator is an essential component in all forms of radio communication equipment. The advantage of using this device is that it makes communication over long distances possible. Any signal that needs to be transmitted over air cannot be directly transmitted through an antenna in original form, as it may get damped or lose its energy over long distances. Hence, these modulators are used in most signal transmitters. They take in the electrical signal and superimpose it or modulate it to a high frequency radio wave, which is then transmitted. Radio waves can be transmitted over long distances, without getting damped and the signal is received on the other end. At the receiving end the signal is demodulated, that is converted back to original form and then used. Radio stations have RF modulators in their transmitting apparatus.

Another important application is the interfacing of DVD players, gaming consoles and other digital output devices with old television sets. Old television sets have RF/coaxial-only inputs, which make connection of a DVD player with non-RF output impossible, due to incompatibility. This problem can be solved by the use of a modulator, which converts the video as well as audio signal output of a DVD player in to a single RF signal. This enables the rendering of those signals even in old televisions. Nowadays, many DVD players and gaming consoles have inbuilt modulators to take care of this problem. Multichannel modulators are used in the distribution of audio/video channels. They can be given multiple audio and video inputs, which is converted in to a single radio frequency output.

External RF modulator devices are available in the market, that can save our old television sets from redundancy with RF coaxial inputs and use them with latest digital devices.