o achieve optimum results from digitized data acquisition systems, engineers must keep in mind that they are dealing with the analog world through a sampled-data process. That sampling process imposes restrictions on the input signal spectrum that can be applied to the system’s analog-to-digital converter (ADC). Consequently, an engineer must pay very careful attention to the front-end analog (antialiasing) filtering that precedes any data conversion.
Whether an engineer designs the filters himself or buys filter modules, he must understand the role a presampling filter plays in a digital signal-acquisition system. When digitally sampling a dc system, a good filter eliminates noise but allows a change in signal to settle out in a reasonable time.
To digitally acquire ac signals, presampling…
19 Sep 2014