NTSC/PAL-M discrimination circuit and chrominance signal reproducing method

Abstract

A circuit discriminates a broadcasting system of a signal recorded in a video tape and is used in a method for reproducing a chrominance signal adopting the circuit. The circuit has: a chrominance signal demodulator for demodulating a chrominance signal from a down-converted chrominance signal, in response to a head switching pulse and a broadcasting system discrimination signal for discriminating the NTSC and PAL-M systems. A phase difference detector is connected to the chrominance signal demodulator for detecting a phase difference between the demodulated chrominance signal output from the chrominance signal demodulator and a reference chrominance signal. An error discriminator generates an error signal indicating the accordance between a broadcasting system which is designated by the broadcasting system discrimination signal and that of the down-converted chrominance signal, based upon the output status of the phase difference detector. The broadcasting system discrimination signal itself is generated in response to the error signal provided from the error discriminator. Thereby, based upon detected phase difference errors, the chrominance signal demodulator functions according to the correct broadcast system so as to compatible with the broadcast system used in recording to the videotape.

Dependencies are inferred from the claim text.