EQUALIZER FOR DIGITAL VIDEO DISK

PROBLEM TO BE SOLVED: To minimize the number of elements and to secure reliability by summing a signal which is a RF input signal multiplied by a factor C before delayed by 2T and a signal multiplied by the factor C and delayed further by 4T, and outputting an RF signal with an equalized frequency characteristic. SOLUTION: A 2T delay part 14 is comprised of all-pass filter and a 4T delay part is comprised of two all-pass filters connected in series. A signal which is a RF input signal multiplied by a factor C after passing through a 2nd buffer 12, a signal which is the RF signal multiplied by the factor C after it has been delayed by passing through a 1st buffer 11 and a 2T delay part 14, and a signal which is the RF signal multiplied by the factor C after delayed by 4T by passing through a 3rd buffer 13 and 4T delay part 15 are summed by an adder 20, and an RF signal with an equalized frequency characteristic is outputted through a low-pass filter 30. This output has an operation characteristic similar to that of a 5-tap universal filter configuration, and improves a characteristic of the summed signal.