PURPOSE: To miniaturize without causing picture quality degradation by converting a sampling frequency after converting an input digital signal into a pulse density modulation signal by using a noise correcting technique fit for IC.
CONSTITUTION: The title device is equipped with a pulse density modulator 12 to receive an input PCM signal (a) of a sampling frequency A inputted through an input terminal 1 and convert it into a pulse density modulation signal (c) of a data rate C, and a decimation filter 3 to receive the pulse density modulation signal (c), convert it into a PCM signal of a sampling frequency B and give it to an output terminal 4. After the input digital signal (a) is converted into the pulse density modulation signal (c) by using the noise correcting technique, it is converted to the output digital signal (b) having the target sampling frequency and therefore, a circuit to increase the sampling frequency to the least common multiple of the sampling frequencies of the input digital signal (a) and the output digital signal (b) can be realized with a digital circuit. Thus, the device can be miniaturized without causing the picture quality degradation.
MIYAKOSHI KAZUMITSU
MURAKAMI HIROBUMI
