Title :
A multi-channel decimator for a tri-level delta-sigma modulator
Author :
Bernadas, Sal ; Thompson, Charles
Author_Institution :
Crystal Semicond. Corp., Austin, TX, USA
Abstract :
An 8-channel decimation filter, cascadable to 1024 channels, for use with a tri-level delta-sigma modulator (DSM) is described. The filter incorporates a least mean squares (LMS) adaptive correction algorithm to digitally correct the tri-level DSM input data. Additionally, digital offset and gain calibration features and output limiting circuitry reduce the requirements on the analog input to the DSM. The decimation ratio is 128 to 1 and the output data is 22 bits with an integrated floor of -116 dB. The filter coefficient design procedure was unique requiring both impulse response and frequency response optimization. LMS correction can improve the Signal-Noise Ratio by 40 dB
Keywords :
FIR filters; digital filters; frequency response; least squares approximations; modulators; sigma-delta modulation; transient response; 22 bit; 8-channel decimation filter; LMS adaptive correction algorithm; SNR; analog input; decimation ratio; digital offset; filter coefficient design; frequency response optimization; gain calibration; impulse response optimization; integrated floor; multi-channel decimator; output data; output limiting circuitry; signal-noise ratio; tri-level delta-sigma modulator; Calibration; Delta modulation; Design optimization; Finite impulse response filter; Frequency response; Least squares approximation; Linearity; Noise generators; Noise shaping; Semiconductor device noise;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on
Conference_Location :
Adelaide, SA
Print_ISBN :
0-7803-1775-0
DOI :
10.1109/ICASSP.1994.389605
