  This paper proposes a signal processing methodology of communication system
and realized that circuits using operational transconductance amplifier (OTA).
Two important classes of communication circuit, delta modulator and compander
have been designed using that procedure. In the first implementation coded
pulse modulation system is demonstrated which employ sampling, quantizing and
coding to convert analog waveforms to digital signals while the second gives
data compression and expansion in digital communication system. The proposed
compander circuit is realized with operational transconductance amplifier and
diode. Required power supply to operate the circuit is 3.5V. Performance of the
circuits realized with OTAs has been demonstrated through SPICE simulation.
