Yves Mazoyer

A 5-V CMOS programmable acoustic front-end for ISDN terminals and digital telephone sets

A 5-V CMOS programmable acoustic front-end IC for ISDN terminal and digital telephone set applications is presented. The chip performs PCM codec and filter functions, fulfilling all D3/D4 and CCITT specs. Moreover, it implements the main analog interfaces required for the speech channel (low-noise microphone preamplifier, earpiece and loudspeaker drivers, sidetone, antilarsen control) and tone/ring/DTMF generation without external components. The device can be controlled by a microprocessor or a HDLC controller via a four wire separated control interface or by means of a serial control channel multiplexed with the PCM voice/data channel in a GCI compatible format. Chip area is 30 mm/sup 2/ in a 1.5-/spl mu/m CMOS technology. The active/stand-by power consumption is 60 mW/0.2 mW from a single 5-V supply. All circuits are designed to meet performance objectives over a voltage range from 4.5 V to 5.5 V and a temperature range from -40/spl deg/C up to 85/spl deg/C. >

A 5V CMOS Programmable Acoustic Front-End for ISDN Terminals and Digital Telephone Sets

A 5V programmable acoustic front-end IC for ISDN terminal and digital telephone set applications is presented. The chip performs PCM codec and filter functions fulfilling and exceeding all D3/D4 and CCITT specs. It implements the analog interfaces required for the speech (low noise microphone preamplifier, earpiece and loudspeaker drivers, sidetone, antilarsen control) and tone/ring/DTMF generation without external components. The device can be controlled by a microprocessor or a HDLC controller via a separate four wire control interface or by means of a serial control channel multiplexed with the PCM voice/data in a GCI compatible format. Chip area is 30 mm2 in a 1.5¿ CMOS technology. Active/stand-by power consumption is 60mW/0.2mW from a single 5V supply.

A CMOS fully integrated antilarsen system for digital telephones

An integrated CMOS antilarson system that requires no external components is presented. Speech time constants as long as 100 ms are digitally realized. A 12-dB antilarsen depth and a 6-dB hysteresis are provided for the specific application where the system is involved, but both of them and the voice time constants can be register programmed to different values. The extra area added to the chip for the antilarsen function is only 0.5 mm/sup 2/ in a 1.5- mu m CMOS technology. >