Patent ID: 6429797
Filing Date: 2002-08-06
Classification: H03H

Abstract:
A bandpass analog to digital converter comprising:a bandpass delta sigma modulator for converting a signal having a nominal frequency of Fc to an oversampled digital signal of a bit rate of Fs, where Fs=N*Fc, N=6; a digital decimation filter for converting the signal from said delta sigma modulator to a multibit digital signal having a nyquist sampling rate of Fs/N comprising: a first multiplier for multiplying said digital signal from said sigma delta modulator by COS(&pgr;*nT/3) for producing a digital signal at a nyquist rate; a second multiplier for multiplying said digital signal from said sigma delta modulator by SIN(&pgr;*nT/3) for producing a digital signal at a nyquist rate; first and second low pass filters connected to filter respective of said first and second signals from said first and second multipliers producing real and imaginary signals, and a third low pass filter to filter said real and imaginary signals from said first and second low pass filters.