Overview of Digital Filter Design and Design Stages:
Digital Filter is designed in discrete time signal to reduce or enhance certain aspects of signal.
(i.e. for example to remove some harmonics in a signal.)
This can be done with Analog filter too. But the reason why people prefer digital filter is its reliability over Analog signal. Analog Signal need not behave same with the variations in temperature, frequency and other conditions. But the digital filter don't have Such problems as the digital filter coefficients will be programmed or the values will be stored in it, this makes the filter output depend only on the values stored or programmed. So the reliability and repeatability of Digital filter makes it more advantageous than the Analog filter design.
Basic Digital design stages or the components used in Digital Filter are
-->Analog to Digital Converter (To convert analog input to digital).
-->Microprocessor (To Store the data).
-->Digital to analog Converter (To Get the final Continues Signal Output).
Main Disadvantage of this filter is the cost involved with design, due to the number of stages involved and also due to the need of memory elements to store data. These are the main reasons why the digital filters were not preferred once.
The briefing on "Advantages and Disadvantages of Digital filter."
Enjoy. Thank you. :D