In this project we learned the basics of realizing filters both in analog and digital forms. While we studied only the affects of these filters on sound signals, the concepts we learned could also be applied to other signals.

We found that there are many factors to consider when choosing between analog and digital filters. For simple functions, analog filters provide effective performance at low cost, especially when the signal is natively analog. Digital filters, on the other hand, are the best choice for more complex filtering functions which are hard to realize in analog circuitry because of component tolerances or sheer number of components. There are also special cases which dictate the use of one kind of filter. For example, very high frequency signals are more easily filtered with analog technology, and filters which must look at future values are better suited for digital implementation.

In the precess of building these filters we also found out something about the "learning curve" of each. Analog filters require a good deal of knowledge about analog circuitry for proper realization, but the actual design of the filters is relatively simple, involving simple math equations. Digital filters (using computer implementation) do not require a particularly advanced knowledge of computers as a whole, but require some time to understand the syntax and interaction of the hardware/software combination. This is not the case in analog where, for example, changing op amps requires no significant education. However, once one masters a digital filtering hardware/software combination, the possibilities are limited only be the complexity of the software and the power of the processor, giving the power to reconfigue a filter in a matter of seconds even when using extremely complex filters.

It is clear that engineers must weigh the benefits of analog and digital filtering methods in each design. Cost, efficiency, ease of manipulation, and other factors come into play in these decisions. We hope that the knowledge that we have gained in this project will help us to make the right filtering decisions as we develop our engineering skills.

Breakdown of Responsibilities

The work that went into our project was broken down approximately equally among all group members. Tom designed and built all of the analog filters and set up the interface with the computer. Randy developed the Matlab code used for the digital filters. Ben also researched digital filtering in Matlab and created several signals. Sam designed and wrote the webpage, although all members contributed to its content. Everyone was involved in creating the images and audio on the webpage. Finally, Tom, Sam, and Randy put together the poster presentation.