Superheterodyne transmitter

Superheterodyne transmitter is a radio or TV transmitter which uses an intermediate frequency signal in addition to radio frequency signal.

In some transmitters, the baseband information signal (audio (AF), video (VF) etc.)

After stages for correction, equalization and sometimes amplification, the IF signal is converted to an RF signal by a stage named frequency mixer or frequency converter.

The other input to the mixer is a high frequency subcarrier signal.

The two signals are multiplied to give; Applying well known rules of trigonometry; A filter at the output of the mixer filters out one of the terms at the right (usually the summation) leaving RF Here