ABSTRACT
Amplifiers and limiters are among the important building blocks of communication circuits. This chapter deals with two different types of amplifiers which are limiting amplifiers and automatic gain controlled (AGC) amplifiers. The main amplifier goal is to amplify the received signal from a transimpedance amplifier. Amplification level must be enough to satisfy the required input signal for subsequent stages such as clock and data recovery circuits. AGC circuits are usually made of an amplifier in which its gain can be adjusted and a mechanism to control that gain for different input signals provides a desired output signal. The chapter introduces a number of popular techniques to control the gain of an amplifier stage. It also introduces a structure to investigate the level of the signal passing through the receiver chain of amplifiers. Limiter circuits are used in frequency modulation applications to remove the unwanted amplitude modulation.
