A CMOS Modem Analog Processor for V.22bis Modems

A mixed analog/digital chip that forms the core of a medium- speed modem for use on the public switched telephone network is described. It meets CCITT and AT&T requirements for data transmission at 2400 and 1200 bit/sec. and the AT&T requirements for 300 bit/sec operation. The chip is implemented in a 1.75 micron analog CMOS process and occupies 32.4 mm sup 2. The device is powered by a single +5 volt supply and consumes less than 115 mW. The architecture and circuit implementation are described and experimental results are given.