OVERSAMPLING D/A CONVERTER, OVERSAMPLING A/D CONVERTER, AND SWITCHED CAPACITOR INTEGRATOR

摘要

PROBLEM TO BE SOLVED: To provide an oversampling D/A converter of a compact size and low power consumption.;SOLUTION: The oversampling D/A converter D/A-converts digital data into 14 bits, in which a signal of up to 4 kHz frequency has been converted and includes a modulator of a mixed-type modulation system. The mixed-type modulator comprises an adder 201, a predictive filter 202, a noise-shaping filter 203, a quantizer 204, and a delay circuit 205. The modulator of this constitution inputs only 11 bits out of the 14-bit digital data. The predictive filter 202 is constituted by a 6-bit integrator, and only 3 bits out of the 6-bit predictive signal are fed back. Thereby, the bit number of the adder 201 is reduced to 3 bits, with respect to the 14 bits of the input, and the bit number of the integrator for the noise-shaping filter 203 is reduced to 11 bits, with respect to the 14 bits of the input.;COPYRIGHT: (C)2007,JPO&INPIT