Advantages of digital filters
The following list gives some of the main advantages of digital over analog
filters.
- A digital filter is programmable, i.e. its operation is determined
by a program stored in the processor's memory. This means the digital filter can
easily be changed without affecting the circuitry (hardware). An analog filter
can only be changed by redesigning the filter circuit.
- Digital filters are easily designed, tested and implemented
on a general-purpose computer or workstation.
- The characteristics of analog filter circuits (particularly those
containing active components) are subject to drift and are dependent on
temperature. Digital filters do not suffer from these problems, and so are
extremely
stable with respect both to time and temperature.
- Unlike their analog counterparts, digital filters can handle low
frequency signals accurately. As the speed of DSP technology continues to
increase, digital filters are being applied to high frequency signals in the RF
(radio frequency) domain, which in the past was the exclusive preserve of analog
technology.
- Digital filters are very much more versatile in their ability to
process signals in a variety of ways; this includes the ability of some types of
digital filter to adapt to changes in the characteristics of the signal.
Fast DSP processors can handle complex combinations of filters in
parallel or cascade (series), making the hardware requirements relatively simple
and compact in comparison with the equivalent analog circuitry.
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