The most common filter found in a data acquisition
system signal path is a low-pass filter. This type of filter
is usually used to reduce A/D Converter (ADC) aliasing
errors. If there is more than one signal that is applied to
the A/D converter through a multiplexer, each signal
source may have its own set of filter requirements (i.e.,
settling time, fast transition region, etc.). Consequently,
a variety of filters may be required in the circuit prior to
the multiplexer. Usually these filters are implemented
with operational amplifiers (op amps) in combination
with fixed resistors and capacitors.M AN737
Using Digital Potentiometers to Design
Low-Pass Adjustable Filters
ble corner frequency range of 1:100. An example of the
Author: Bonnie C. Baker
digital potentiometer setting for these designs is
Microchip Technology Inc.
summarized in Tables 1, 2 and 3. The fourth scenario
will show the same circuit design, where all three
INTRODUCTION ……
