资料介绍
Analog filters can be found in almost every electronic
circuit. Audio systems use them for preamplification,
equalization, and tone control. In communication sys-
tems, filters are used for tuning in specific frequencies
and eliminating others. Digital signal processing sys-
tems use filters to prevent the aliasing of out-of-band
noise and interference.
This application note investigates the design of analog
filters that reduce the influence of extraneous noise in
data acquisition systems. These types of systems pri-
marily utilize low-pass filters, digital filters or a combina-
tion of both. With the analog low-pass filter, high
frequency noise and interference can be removed from
the signal path prior to the analog-to-digital (A/D) con-
version. In this manner, the digital output code of the
conversion does not contain undesirable aliased har-
monic information. In contrast, a digital filter can be uti-
lized to reduce in-band frequency noise by using
averaging techniques. AN699
Anti-Aliasing, Analog Filters for Data Acquisition Systems
Author: Bonnie C. Baker ANALOG VERSUS DIGITAL FILTERS
Microchip Technology Inc.
A system that includes an analog filter, a digital filter or
both is shown in Figure 1. When an analog filter is
INTRODUCTION implemented, it is done prior to the analog-to-digital
conversion. In contrast, when a digital filter is imple-
Analog filters ca
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