Pal identification circuit

Abstract

In a PAL color television signal receiver including a color demodulator, a source of first timing signals for determining the line by line switching of the color demodulator, and a source of second timing signals coincident with the burst interval of the color signal, a circuit for identifying an incorrect mode of line by line color demodulator switching. A signal representative of the periodic, alternating phase burst component of the color signal is sampled every other image line to derive an identification signal representative of the timing of the burst component. The identification signal is utilized to alter the operation of the source of timing signals to produce timing signals corresponding to a correct switching mode. A sampling circuit employed to derive the identification signal is keyed in response to the first and second timing signals such that the derived signal is suitable for use as a switching mode identification signal, as well as for purposes providing automatic color control (ACC) and color killer control.