FREQUENCY RESPONSE / NORMALISATION AND FILTER CIRCUITS
Introduction

In this chapter the concept of frequency response would be analysed, and its role in  the prediction of the behavior of several filter circuits would be explained. 

Frequency response of a system is a representation of the systems response to sinusoidal inputs at varying frequencies. The output of a linear system to a sinusoidal input is a sinusoid of the same frequency but with different magnitude (gain), and phase

Filter is a frequency selective network that favors certain frequencies of input signals at the expense of others. Three very common types of filter are the low pass filter, the band pass filter and the high pass filter.

Filters are related with the  frequency response analysis, because the behavior of the three different filter types mentioned above, would be explained through the graphical plotting of their individual characteristics (magnitude and phase). This graphical plotting of the magnitude and phase response is referred to as bode plots.