Details of transmission systems, not covered by a single one of groups; Details of transmission systems not characterised by the medium used for transmission

Classification Context

Section:

ELECTRICITY

Class:

ELECTRIC COMMUNICATION TECHNIQUE

Subclass:

TRANSMISSION

Scope Notes

Glossary: Homodyne receiver A receiver which involves multiplying the modulated received signal by a local oscillator which has the same frequency as that associated with the received signal, so that the received signal will be directly converted into the baseband. Superheterodyne receiver superheterodyne receivers A receiver in which the frequency of the incoming signal is reduced in a mixer or frequency changer by heterodyning with another frequency at the local oscillator. (Heterodyning: combining two sinusoidal frequencies radio frequency waves in a non-linear device resulting in sum and difference frequencies). Synchrodyne receiver synchrodyne receivers A receiver in which a mixing carrier signal is inserted in exact synchronism with the original carrier at the transmitter. Used for the selective detection of signals coded in a certain way. | Limiting references: Demodulation or transference of modulation from one carrier to another

Child Classifications

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• H04B 1/02 Transmitters
• H04B 1/06 Receivers
• H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• H04B 1/59 Responders; Transponders
• H04B 1/6 Supervising unattended repeaters
• H04B 1/62 for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
• H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission
• H04B 1/68 for wholly or partially suppressing the carrier or one side band
• H04B 1/69 Spread spectrum techniques
• H04B 1/72 Circuits or components for simulating antennas, e.g. dummy antennas
• H04B 1/74 for increasing reliability, e.g. using redundant or spare channels or apparatus
• H04B 1/76 Pilot transmitters or receivers for control of transmission or for equalising