preparing an analog signal before digitizing it: amplifying the signal, removing frequencies above half the sampling rate (the Nyquist frequency), linearizing it, and so on, although digital processing now can perform linearization and other traditional signal conditioning tasks more effectively than analog circuitry

Electronic manipulation of signals to produce a desired effect. Examples are amplification and filtering

Makes a signal suitable for input to an analogue-to-digital converter. For example, a signal may be filtered to remove noise, or amplified to meet the range of the A-D converter.

Analog Input Buffers 5b Modules Solid-State Relays

Imagine feeding the output of a temperature sensor, which is in millivolts, to an Analog-to-digital converter to be processed. Is it possible for the Analog-to-Digital converter to process such a minute voltage amplitude? The answer is probably no.