Narda-MITEQ

Modulators

A modulator commonly varies some aspect (amplitude, phase or frequency) of an RF carrier (fo, in proportion to a much lower frequency video or digital input signal (fm). In general, the input frequency components of the modulation typically extend from DC to 100 MHz, except for fast data links.In order to preserve the information content superimposed on the RF carrier, one must insure that the output system bandwidth is adequate to pass both upper and lower sidebands (i.e. fo + fm) without distortion. In fact, system amplifier and channel distortion often will add residual AM or PM modulation to an otherwise clean transmitter.