Acoustical Manufacturing Co. QUAD MULTIPLEX DECODER, Инструкция, Страница: 3 / 16

THE PILOT TONE SYSTEM OF STEREOPHONIC BROADCASTING
The pilot tone (otherwise known as the Zenith
-
GE) system of stereophonic broadcasting allows
any VHF - FM tuner to receive a mono version of the programme which is the addition of the
original left and right hand channels.
The stereo information is the difference between the left and right hand channels. This has to be
recovered separately from the sum signal and it is transmitted as a signal above the limits of audi­
bility. The listener with a mono receiver is therefore not aware of the stereo information.
The purpose of the multiplex decoder is to translate these inaudible difference signals and to com­
bine them with the sum signal in such a way that the original left and right hand channels re-appear
separately.
THE QUAD MULTIPLEX DECODER
The QUAD multiplex decoder is designed specifically for use with the QUAD FM tuner and
QUAD 22 control unit.
Its internal mono-stereo electronic switching is operated remotely from the QUAD 22 controls. It
may. therefore. be concealed within the equipment cabinet without any need for access after
installation.
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