AUTOMATIC METHOD FOR IDENTIFYING A COLOR TV STANDARD

摘要

A method for automatically identifying the PAL or NTSC color TV standard comprises the following steps: providing a first demodulation signal (IC1) with the regenerated 90 DEG -phased sub-carrier; providing a second demodulation signal at the reference frequency of one of the colors (FOR) of the SECAM standard; providing a first voltage (VC1) by integrating the first demodulation signal (IC1), and providing a first associated logic criterion (C1), simultaneously applying the first signal (IC1) at the input of an inverter switched according to the rate of a non-half line-frequency phased signal (FL/2), providing a second voltage (VC2) by integrating the output signal (ICC) of the inverter (31), and providing a second associated logic criterion (C2); similarly providing, but from the second demodulation signal (IC2), the first logic criterion (C1) and the second logic criterion (C2); and identifying the standard received as a function of the state of the first and second logic criteria (C1 and C2).