Title :
An adaptive line equalizer LSI for ISDN subscriber loops
Author :
Inami, Daijiro ; Kuraishi, Yoshiaki ; Fushimi, Shigeo ; Takahashi, Yutaka ; Nukada, Yasuaki ; Kameyama, Shigeharu ; Shiratori, Akihiro
Author_Institution :
NEC Corp., Kanagawa, Japan
fDate :
6/1/1988 12:00:00 AM
Abstract :
An adaptive line equalizer LSI applied to a time-compression multiplexing transmission system, which transfers 320-kb/s AMI coded signals to provide the 144-kb/s (2B+D) transmission capacity recommended by CCITT, is described. The square root f equalizer can adaptively equalize up to 53-dB cable loss at Nyquist frequency (160 kHz), using switched-capacitor filter (SCF) technology. The equalizer transfer function is optimized in the time domain. The coarse automatic gain control circuit is composed of a fourth-order SCF. A high-speed operational amplifier, with wide output voltage swing and excellent stability against load capacitance variation, has been developed. The equalizer enables 5.5-km transmission over 0.5-mm diameter cable with two bridged taps because of its wide gain dynamic range and the use of decision feedback. A small chip size, 6.2*6.6 mm, and low power consumption, 80 mW (from a 5-V single supply), are achieved in 3- mu m CMOS technology.<>
Keywords :
CMOS integrated circuits; ISDN; adaptive systems; automatic gain control; equalisers; large scale integration; switched capacitor filters; 160 kHz; 3 micron; 320 kbit/s; 5 V; 5.5 km; 53 dB; 80 mW; AMI coded signals; CMOS technology; ISDN subscriber loops; Nyquist frequency; adaptive line equalizer LSI; bridged taps; chip size; coarse automatic gain control circuit; decision feedback; equalizer transfer function; fourth-order SCF; high-speed operational amplifier; low power consumption; stability against load capacitance variation; switched-capacitor filter; time domain; time-compression multiplexing transmission system; wide gain dynamic range; wide output voltage swing; Adaptive equalizers; Adaptive filters; Ambient intelligence; CMOS technology; Frequency; Gain control; ISDN; Large scale integration; Subscriber loops; Transfer functions;
Journal_Title :
Solid-State Circuits, IEEE Journal of
