DIGITAL PAL COLOUR TELEVISION SIGNAL DEMODULATORS

• Main Authors: JAMES HEDLEY WILKINSON, DAVID MORRIS CREED
• Format: Patent
• Language: English
• Published: 11.06.1986
• Edition: 3
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

A digital PAL color television signal demodulator for demodulating the U and V color component signals from an input chrominance signal derived from a PAL color television signal which has been digitized by being sampled a predetermined number of times per horizontal line comprises a first memory storing values representing the phases of the sub-carrier signal, on which the U and V color component signals have been modulated, at the first sample position of each of the successive lines of four fields of the television signal, a second memory storing values representing the relative phases of successive sample positions along a horizontal line, means for deriving from the memories values representing the phases of successive sample positions of each of the successive samples in eight fields of the television signal, means to derive from the values derived from the memories quadrature amplitude values of the sub-carrier in synchronism with a sample frequency of the input chrominance signal, and multipliers and low-pass filters for demodulating the input chrominance signal with each of the quadrature amplitude values of the sub-carriers and for deriving the U and V color component signals.