Analog televisions use RF modulation to convert a broadcast signal into an analog format.
Radio frequency refers to the rate of oscillation, or spinning, that corresponds to electrical signal frequencies used to produce radio waves. RF, or radio frequency, modulators take an input signal and modify the format of the resulting output signal.
Signal Transmission
Analog TV signals are transmitted by a television station and received by the television's antenna. RF modulators use the signals generated by a composite video, or soundless, picture-only television signal, and generates a PAL broadcast signal that is fed into the television's coaxial connector. A PAL, or phase alternate line, is an analog TV system that uses frequency modulation to reformat the video signal and add audio.
Frequency Modulation
Frequency modulation involves changing the frequency of a radio wave to make it compatible with the amplitude of the inputted, or incoming, signal. Amplitude refers to the degree of change in the oscillating variable that occurs with each oscillation in the wave. The modulating signal, or data-bearing signal, alters the instantaneous frequency generated by the carrier. The amplitude of the carrier remains constant, enabling the modulator to take the difference in frequencies and generate formatted radio wave signals.
Applications
RF modulators are used in DVD players, VCR players and car CD changers. RF modulators are also used for speech and music in hi-fidelity broadcasts.
Tags: broadcast signal, radio wave
