Analogue Filter Design

In electronics, filters are required for all sorts of applications, ranging from a simple audio circuit to the speech processor in a GSM phone. Filter theory being complex stuff for the average electronics worker and certainly no part of everyday chores, a couple of Internet addresses may come in handy if you’re suddenly faced with selecting and dimensioning a filter for an application on hand. In this month’s instalment of Electronics Online we look at a dozen or so calculation aids for analogue filters.Electronic filters represent a complex matter which is not, or not fully, mastered by many electronics enthusiasts. Not to worry, because lots of professional engineers will also admit defeat to the niceties of modern filter design. Fortunately, neither the hobbyist nor the professional worker needs to have a few dozen equations in his head — what matters is to know where the information can be found when it is needed. To help you on the way, and perhaps add a few bookmarks in your Favourites folder, we searched the Internet for software tools that considerably lighten the job of passive and active analogue filter design.