Modification of television sound signal - is by conversion of sound signal standard without affecting vision signal and is for cable transmission (OE150576)

摘要

The modifier circuit consists of a separation stage (3, 4, 5) which separates sound frequency from vision frequency. Modulator (7) with oscillator (8) converts sound carrier to intermediate frequency, amplified and band-limited by stages (9, 10, 11). Frequency displacement is achieved by an oscillator (13) and a modulator (12) to change the level relative to vision adjusted by a control (15). Enables different transmission standards to be received on a common aerial and to converted to the same frequency separation or to relative levels for reception by a standard receiver.