Title :
A CMOS analog front end circuit for an FDM-based ADSL system
Author :
Zhong-Yuan Chang ; Macq, D. ; Haspeslagh, D. ; Spruyt, P. ; Goffart, B.
Author_Institution :
Alcatel Bell Telephone, Antwerp, Belgium
Abstract :
To cope with the high attenuation and the large echo return of copper telephone wire, the analog front end must feature low-noise enhancement, accurate channel filtering and high dynamic range. Two 14th-order continuous-time bandpass filters with on-chip automatic tuning provide the required channel separation in a narrow transition band (i.e. 96 kHz-138 kHz). A Gm-C integrator achieve over 60dB linearity of these filters. By using 4th-order /spl Sigma//spl Delta/ ADC and 6th order /spl Sigma//spl Delta/ DAC architectures, 12 b data conversion accuracy is achieved at 1.54 MHz Nyquist rate.
Keywords :
CMOS analogue integrated circuits; band-pass filters; circuit tuning; continuous time filters; frequency division multiplexing; sigma-delta modulation; subscriber loops; /spl Sigma//spl Delta/ ADC architecture; /spl Sigma//spl Delta/ DAC architecture; 1.54 MHz; 96 to 138 kHz; CMOS analog front end circuit; FDM-based ADSL system; Gm-C integrator; Nyquist rate; attenuation; channel filtering; continuous-time bandpass filters; copper telephone wire; data conversion; dynamic range; echo; linearity; low-noise enhancement; on-chip automatic tuning; Attenuation; Band pass filters; CMOS analog integrated circuits; Circuit optimization; Copper; Dynamic range; Filtering; Linearity; Telephony; Wire;
Conference_Titel :
Solid-State Circuits Conference, 1995. Digest of Technical Papers. 41st ISSCC, 1995 IEEE International
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-7803-2495-1
DOI :
10.1109/ISSCC.1995.535576
