Patent ID: 6304200
Filing Date: 2001-10-16
Classification: H03M

Abstract:
A digital/analog conversion apparatus for converting an input digital signal into an analog signal, comprising:first bit conversion means for converting a multi-bit signal as a first digital signal sampled with a sampling frequency of Fs Hz and quantized with M bits into a first digital signal of N bits, where M is an integer equal to or greater than 2, and where N is an integer equal to or smaller than M;second bit conversion means for converting a one-bit signal as a second digital signal sampled with another sampling frequency of k.times.Fs Hz and quantized with 1 bit into a second digital signal of N bits, where k is an integer equal to or greater than 2;signal selection means for alternatively selecting one of the first digital signal of N bits obtained by said first bit conversion means and the second digital signal of N bits obtained by said second bit conversion means;pulse width modulation means for pulse width modulating the first or second N-bit signal selected by said signal selection means; andfilter means for filtering a pulse width modulated signal from said pulse width modulation means to pass only predetermined components of the pulse width modulated signal in a low frequency region therethrough.