PURPOSE: To reproduce an analog signal compensating the aperture effect without temperature dependancy while not requiring a highly accurate delay line by arranging a digital filter having an amplitude frequency characteristic compensating the aperture effect and a linear phase characteristic before a D/A converter.

CONSTITUTION: The digital filter 7 receiving an n-bit digital data (a) inputted to a PCM receiver has a flat delay characteristic, i.e., a linear phase characteristic and a frequency characteristic compensating the amplitude frequency characteristic of the D/A converter 8, processes the input digital data (a) so as to compensate the aperture effect and outputs an m-bit data (b) to the D/A converter 8. The D/A converter converts the m-bit PCM signal into a PSM signal to output an analog signal So. A low pass filter 9 receiving the signal So has a limit band having ≤1/2 of a sampling frequency fs and outputs an original analog signal S1 while recovering it. The amplitude characteristic X(f) of the digital filter 7 is expresses in equation I, where H(f) is the amplitude characteristic of the D/A converter when the frequency range is ≤1/2fs.