HDTV LUMINANCE FREQUENCY-AXIS MULTIPLEXING SYSTEM

摘要

Disclosed are multiplex signal processing apparatuses in a signal transmitting and receiving system. The apparatus at the transmitting side comprises: a first amplitude-modulator for modulating a first carrier by a main signal to obtain a vestigial side band, amplitude-modulated main signal; a second amplitude-modulator for modulating a second carrier which is same in frequency to and different in phase by 90 DEG from the first carrier by a multiplex signal to obtain a double side band, amplitude-modulated multiplex signal; an inverse Nyquist filter for filtering this signal to obtain a vestigial side band, amplitude-modulated multiplex signal; and an adder for adding the vestigial side band, amplitude-modulated main and multiplex signals to obtain a multiplexed signal. The apparatus at the receiving side comprises: a Nyquist filter for filtering the multiplexed signal; a carrier regenerator for regenerating the first and second carriers from the multiplexed signal; a main signal detector for detecting the main signal from the multiplexed signal passed through the Nyquist filter by using the first carrier; a filter for removing quadrature distortion from the multiplexed signal; and a multiplex signal detector for detecting the multiplex signal from the multiplexed signal passed through the filter by using the second carrier. This invention, when applied to the television system, provides a large quantity of additional information while keeping compativility with the conventional television system.