SECAMMPAL SYSTEM COLOR TELEVISION RECEIVER

摘要

PURPOSE:To secure the accurate synchronization between the PAL identification circuit and the SECAM color signal only through the output of the modulator by piling the color identification signal onto the position corresponding to the PAL burst signal, and thus ensuring the steady operation with a simple constitution of the circuit. CONSTITUTION:In case the carrier suppression phase modulation is given to the PAL color subcarrier with the SECAM color signal once demodulated, the SECAM color signal of input terminal 11 is demodulated through SECAM demodulator 1 and then supplied to DC potential shift circuit 14. Circuit 14 fixes the DC level at the position corresponding to the burst signal of the PAL signal to the fixed level and then supplies it to carrier suppression phase modulator 2. At the same time, the phase sift is given through 0 deg./90 deg. phase-shift circuit 3 to the color subcarrier sent from PAL color subcarrier oscillator 9 and in synchronization with the SECAM color signal sent in the line sequential system from 1HFF5 driven by SECAM identification circuit 4, and only the signal corresponding to the position of the burst of the PAL color signal is supplied to modulator 2. Then the color identification signal is piled onto the position corresponding to the PAL burst signal.