Burst phase

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Burst phase is the first ten cycles of colour burst in the "porch" of the synchronising pulse in PAL (Phase Alternation Line) format. The frequency of this burst is 4.43361875 MHz, it is precise to half a cycle and is used as the reference frequency to synchronise the local oscillators of the colour decoder in a PAL television receiver.

This colour burst is sometimes called the "Swinging Burst", as it swings +/- 45 degrees line by line (hence the expression "Phase alternating line". This swing is used to set the centre frequency of the colour reference oscillator in the decoder (as mentioned above). The actual swing of the burst phase is used to identify a PAL and NON-PAL line and produces what is known as the IDENT signal.