PURPOSE: To provide a PCM codec in which characteristics of band-pass filters can be switched according to a sampling frequency and an optimum voice quality can be always obtained with respect to the large extent of sampling frequencies.
CONSTITUTION: This PCM codec outputting a data signal by selecting the frequency of an input voice signal with a band-pass filter 101 and outputting a voice signal by selecting the frequency of an input data signal with a band-pass filter 112 is provided with a programmable frequency divider 108 and has a PLL circuit outputting a clock based on a sampling clock, a programmable frequency divider 110 frequency-dividing the clock of the PLL circuit and a PLL control circuit 111 controlling frequency dividing ratios of programmable frequency dividers 108, 110 based on an input command. Then, this device is constituted so that operating characteristics of the PLL circuit C1 and band-pass filters 101, 112 are switched in accordance with the frequency of the sampling clock by frequency dividing ratios of programmable frequency dividers 108, 110.
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