SECAM Line Identification and PAL Switch

A method of performing SECAM line identification in an analog television, wherein the SECAM line comprises one of a red line and a blue line, said method comprising:

• accumulating, using an accumulator, a frequency modulation (FM) demodulated output corresponding to a color reference tone for each said SECAM line;
• receiving, in a first leakage average filter, a first result from said accumulator;
• receiving, in a second leakage average filter, a second result from said accumulator;
• comparing said first result with said second result,
• wherein when there is change between a relative magnitude of said first leakage average filter and said second leakage average filter, a switch command is issued to said first leakage average filter and said second leakage average filter by a line decision block, and
• wherein said line decision block switches a stored value between said first leakage average filter and said second leakage average filter.

An apparatus for soft-decision based PAL switch detection in an analog television, said apparatus comprising:

• a burst locked oscillator (BLO) that receives a composite video signal as input and produces an instantaneous PAL switch signal for each line;
• a leakage average filter that receives said instantaneous PAL switch signal and filters noise from an output received from said BLO;
• and
• a switch detection block that is operatively connected to said leakage average filter and receives a filtered output from said leakage average filter, wherein said switch detection block makes a decision based on a sign of said filtered output of said leakage average filter.

A method of detecting a PAL switch based on a soft-decision in an analog television, said method comprising:

• receiving, in a burst locked oscillator (BLO), a composite video signal as input;
• producing an instantaneous PAL switch signal for each line in said BLO;
• receiving, in a leakage average filter said instantaneous PAL switch signal and filtering noise from an output received from said BLO;
• receiving, in a switch detection block, a filtered output from said leakage average filter;
• and
• making a detection decision based on a sign of said filtered output of said leakage average filter.