Practical Filter Design (1)

58 J EE aPRACTICAL FILTER DESIGN (1) There are still many electronics constructors who are not fully au fait with the operation and calculation of filters. This often results in not always fully correct standard solutions and difficulties when it comes to tracing faults. This new series of articles will attempt to explain the operation of the most frequently encountered types of filter and to make the design of them accessible to everyone. It is hard to think of any piece of elec- filter functions. In this series, all net- tronic equipment, be it audio, HF, radar, works will be classified according to television, or computing that does not their mode of operation. contain some kind of filter. 1. Low-pass, which passes all signals from d.c. to a certain frequency called the cut-off frequency. Above that fre- quency, all signals are attenuated or sup- pressed altogether. 2. High-pass, in which all signals below a given frequency, again called cut-off frequency, are attenuated or sup...