An NTSC system chrominance signal demodulation apparatus is provided with
a clock timing change circuit for burst-locking an input signal under the
state where the phase is shifted by 90 degrees for every line, and phase
axis rotation circuits for performing phase axis rotation, thereby to
enable conversion of the phase axis of the burst signal. Therefore,
demodulation of a PAL system chrominance signal can be carried out as
well as demodulation of an NTSC system chrominance signal, and thereby
demodulation of chrominance signals can be carried out using a common
device regardless of the broadcast systems such as NTSC and PAL. Further,
demodulation of chrominance signals can be carried out even under adverse
conditions such as weak electric field or level compression of the burst
signal.