Chapter 3 - Analog Signal Conditioning

Abstract

Almost all transducer signals must be conditioned by analog circuitry before they can be digitized and used by a computer. This conditioning often includes amplification and filtering. The most common analog circuit semiconductor component is the operational amplifier, called the op amp. The op amp is used in both linear and nonlinear applications involving amplification and signal conditioning. Another special analog circuit, which is useful in data acquisition applications, is the sample-and-hold amplifier. Sample-and-hold amplifier is used as the front end of an analog-to-digital converter (ADC). Apart from these amplifiers, there are many important nonlinear amplifier circuits, such as the log amplifier and the antilog amplifier. Log amplifier is commonly used to compress a signal's large-amplitude dynamic range into something more manageable by other circuits. This chapter discusses the standard filter functions. The standard types of filter responses are low-pass, high-pass, band-pass, and band-reject. The low-pass filter attenuates signals above its cut-off frequency, whereas the high-pass filter attenuates signals below its cut-off frequency. The band-pass filter attenuates frequencies outside of its pass-band range and the band-reject filter attenuates those frequencies within its pass-band range.