Patent ID: 8643783
Filing Date: 2014-02-04
Classification: H04N

Abstract:
1. A method in a television receiver receiving interlaced analog modulated television signals, comprising: generating an IF signal having a low intermediate frequency (low-IF) or zero intermediate frequency (zero-IF) from the received analog modulated television signals, the IF signal being a not-fully-demodulated intermediate frequency (IF) signal; detecting a serration pulse sequence in the IF signal by detecting a first signal level on an envelope of the IF signal, wherein the serration pulse sequence is indicative of an inactive video period in the analog modulated television signal between two successive video display fields; generating a synchronization signal indicative of the detected inactive video period in response to the detected serration pulse sequence in the IF signal; and in response to the synchronization signal, performing measurement and adjustment operations on analog circuitry of the television receiver, wherein generating the synchronization signal indicative of the detected inactive video period in response to the detected serration pulse sequence in the IF signal comprises: generating a vertical field detect signal in response to the detected serration pulse sequence; and generating the synchronization signal based on the vertical field detect signal; and wherein generating the synchronization signal based on the vertical field detect signal comprises: delaying the vertical field detect signal; and using the delayed vertical field detect signal as the synchronization signal.