ABSTRACT
This chapter introduces frequency filter concepts, instructs the student to understand and distinguish filters based on their frequency response and teaches how to build active 1st‐order and 2nd‐order filters using generic circuit topologies. Filters are linear circuits designed to pass or block signals at certain frequencies. That is, it has variable frequency gain, being classified according to their frequency response, such as Low‐Pass, High‐Pass, Band‐Pass, and Band‐Stop. The chapter describes each classification and shows their frequency‐gain graphs. The main parameters of a filter are: passband, stopband, transition band, frequency response, cutoff frequency, 3dB bandwidth, and filter quality factor. Typically, 1st order filters tend to have a slower frequency response, with simpler functions. For 1st order filters, the users restrict themselves to varying the passive elements of an RC passive filter, associated with the use of a noninverting amplifier to increase the gain.
