H03D DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
Introduced: September 1968
Classification Context
- Section:
- ELECTRICITY
- Class:
- ELECTRONIC CIRCUITRY
- Subclass:
- DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
Description
H03D covers circuits and methods for demodulating modulated signals and converting modulation from one carrier frequency to another. This includes detection of amplitude-modulated, frequency-modulated, and phase-modulated signals, as well as frequency conversion and mixing operations in radio and communication receivers. The classification encompasses detector circuits, demodulators, frequency converters, and heterodyne systems used in telecommunications, broadcasting, and radar applications. Excluded are modulation circuits themselves (H03C) and complete receiver systems (H04B).
Scope Notes
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 superheterodyne receivers 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) | Limiting references: Masers, lasers Circuits capable of acting both as modulator and demodulator; balanced modulators , Details applicable to both modulators and frequency changers Demodulating pulses which have been modulated with a continuously variable signal Transforming types of pulse modulation Relay systems, e.g. repeater stations Demodulators adapted for digitally modulated-carrier systems. Synchronous demodulators adapted for colour television Phase locked loops; phase comparators therein -
Related Keywords
8 direct subcodes
Child Classifications
Navigate with arrow keys, Enter to open
- H03D 1/00 Demodulation of amplitude-modulated oscillations
- H03D 11/00 Super-regenerative demodulator circuits
- H03D 13/00 Circuits for comparing the phase or frequency of two mutually-independent oscillations
- H03D 3/00 Demodulation of angle-modulated oscillations
- H03D 5/00 Circuits for demodulating amplitude-modulated or angle-modulated oscillations at will
- H03D 7/00 Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D 9/00 Demodulation or transference of modulation of modulated electromagnetic waves
- H03D 99/00 Subject matter not provided for in other groups of this subclass