Chapter Seven - Signal Processing Circuits

Abstract

This chapter discusses various signal processing circuits. Most of them serve to condition analog signals for subsequent input to another circuit. This chapter examines circuits that can rectify low-amplitude signals, limit the maximum excursion of signals, and change the DC level of waveforms. The first circuits discussed here are the ideal diodes, which behave as though they had perfect or ideal diodes. It produces a peak output that is equal to the input peak. An ideal rectifier circuit can be made with standard silicon diodes and an op amp. An ideal biased clipper, or limiter circuit, has no effect on the input signal as long as it is less than the clipping or reference voltage. An ideal clamper's purpose is to shift the average or DC level of the input signal without altering the waveshape. A peak detector simulates an ideal diode by including it in the feedback loop of an op amp. An integrator produces an output voltage that is proportional to both the duration and amplitude of an input signal. The last circuit mentioned is a differentiator, which produces an output signal that is the first derivative of the input signal. The chapter concludes with certain troubleshooting tips for signal processing circuits.