PURPOSE: To enhance the resistance to noise and the detection sensitivity even if a supply voltage is low, by subjecting a phase detection signal corresponding to the phase difference between a burst signal in a carrier chrominance signal and a reference chrominance subcarrier to exponential expansion after logarithmic compression.

CONSTITUTION: The carrier chrominance signal inputted to an input terminal 1 is supplied to a burst gate circuit 2, and the burst signal is separated by a burst gate pulse and is supplied to a phase detector 4. The reference chrominance subcarrier inputted from a terminal 5 has the phase compared with the phase of the burst signal, and the phase detection signal having a level corresponding to the phase difference is supplied to a logarithmic compression circuit 9. The signal which has the amplitude subjected to logarithmic compression by the circuit 9 has the level shifted by a DC level shifting circuit 10 and has the amplitude restored by an exponential expansion amplifying circuit 11. Thereafter, only the phase detection signal is taken out by a burst gate circuit 12 and is outputted to an output terminal 13 through a low pass filter 6.