A monolithic 1200 baud FSK CMOS modem

An integrated circuit that performs all the modulation, demodulation, filtering, and handshaking required to implement a modem that complies with the Bell 202 and CCITT V.23 standards is described. This double-poly CMOS device uses switched-capacitor techniques to operate at rate of up to 1200, 600, 150, 75, and 5 b/s.