Title :
Switched-capacitor FSK modulator and demodulator in CMOS technology
Author :
Hosticka, Bedrich J. ; Brockherde, Werner ; Kleine, Ulrich ; Zimmer, Günter
fDate :
6/1/1984 12:00:00 AM
Abstract :
A switched-capacitor FSK modulator/demodulator built in silicon-gate CMOS technology is described. The modulator is based on a programmable harmonic oscillator using two stray-insensitive integrators. The centerpiece of the FSK demodulator is a switched-capacitor voltage-controlled oscillator. A simple post-detection processor restores the digital data. Both circuits have been designed for the 600-baud modem channel with 1500 Hz center frequency and ±200 Hz frequency shifts, but the demodulator operates in the 1200-baud channel as well. Due to dynamic biasing the operational amplifiers feature high slew rate, high voltage gain, and low power for capacitive loads.
Keywords :
Demodulators; demodulators; CMOS technology; Circuits; Demodulation; Frequency shift keying; High power amplifiers; Low voltage; Modems; Modulation coding; Operational amplifiers; Voltage-controlled oscillators;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.1984.1052154
