Title :
A chip set for 7 KHz handfree telephony
Author :
Le Scan, P. ; Soler, M. ; Perreal, F. ; Martel, G. ; Closse, E. ; Balestro, F. ; Senn, P. ; Morche, D. ; Jullien, J.P. ; Le Tourneur, G.
Author_Institution :
France Telecom, CNET, Grenoble, France
Abstract :
This paper presents three VLSI circuits developed for an enhanced quality handfree telephone terminal (bandwidth up to 7 KHz). A first circuit performs the intensive computation task required by an adaptive filter of up to 1020 taps at 16 kHz sampling frequency for acoustic echo cancellation (AEC). A microprogrammed DSP with a specific architecture implements the bit rate compression/expansion (IUT G722 recommendation) and controls the gain of the AEC. The third circuit performs AD and DA conversion with corresponding filtering at 16 Ksamples/s with 15 bits resolution. The three circuits have been designed in 1 μ CMOS (AEC and analog front end) and 0,8 μ CMOS technology (DSP). Measure results are also presented
Keywords :
CMOS digital integrated circuits; VLSI; analogue-digital conversion; application specific integrated circuits; digital signal processing chips; echo suppression; telephone sets; telephony; 0.8 mum; 1 μ CMOS; 1 mum; 16 kHz; 7 kHz; AD conversion; ASIC; DA conversion; VLSI circuits; acoustic echo cancellation; adaptive filter; analog front end; bit rate compression; bit rate expansion; chip set; enhanced quality; handfree telephone terminal; handfree telephony; intensive computation task; microprogrammed DSP; sampling frequency; specific architecture; Adaptive filters; Bandwidth; CMOS analog integrated circuits; CMOS technology; Digital signal processing; Echo cancellers; Frequency; Sampling methods; Telephony; Very large scale integration;
Conference_Titel :
Custom Integrated Circuits Conference, 1994., Proceedings of the IEEE 1994
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-1886-2
DOI :
10.1109/CICC.1994.379765
