DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER

**Definition:** This place covers:

Demodulation or transference of signals modulated on a sinusoidal carrier or on electromagnetic waves.

**Limiting references (this place does not cover):** - Masers, lasers -> H01S - Circuits capable of acting both as modulator and demodulator;balanced modulators -> H03C - Details applicable to both modulators and frequency changers -> H03C - Demodulating pulses which have been modulated with a continuously variable signal -> H03K9/00 - Transforming types of pulse modulation -> H03K11/00 - Phase locked loops; phase comparators therein -> H03L7/08 - H03L7/097 - Relay systems, e.g. repeater stations -> H04B7/14 - Demodulators adapted for digitally modulated-carrier systems -> H04L27/00 - Synchronous demodulators adapted for colour television -> H04N9/66

**Glossary:** - Homodyne, synchrodyne or zero-IF receiver: A receiver in which the local oscillator (LO) frequency is set to the same frequency as the received RF carrier frequency resulting in direct conversion of the received signal to a baseband (or zero IF) frequency for information recovery. In a near-zero IF receiver, the LO frequency is set very close to the carrier frequency of the RF signal. - Superheterodyne receiver: A receiver in which a received RF signal is converted to an intermediate frequency (IF) by at least one stage of frequency conversion (e.g. a 'mixer' stage which forms the product of the RF signal and a local oscillator signal)