In a passive analog filter, it is the number of reactive elements. The number of reactive elements is of course related to the differential equation describing the filter response in magnitude and phase. Reactive elements are inductors and capacitors because they both have reactance. Reactance is like resistance for resistors, but it depends on the frequency of the signals it sees. The only real limit is a practical one of how many components you wish to string together; a 20th order filter is certainly possible.Thanks for the reply. What determines the highest order? For instance is it possible to have a 20th order filter or is there a limit?
In theory there is no limit given unlimited computing precision, but in the real world there are several secondary effects that set in that will limit the practical filters. For example, if we designed a band pass filter for a given center frequency with 20 stages and only one of those stages was not tuned right due to component tolerances, we end up with a second order filter (one that could have been built with only two stages) rather than the intended twentieth order filter. So even one bad stage can ruin the whole filter.Thanks for the reply. What determines the highest order? For instance is it possible to have a 20th order filter or is there a limit?
Hi there,In a passive analog filter, it is the number of reactive elements. The number of reactive elements is of course related to the differential equation describing the filter response in magnitude and phase.
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To add to what has already been said, the rolloff voltage response after the filter's corner frequency is equal to the filter order times 6db/octave of frequency change (20dB/decade), Thus a first order filter rolls off at 6dB/octave, a second order at 12dB/octave, etc.Hi all,
Can someone please explain what is exactly the filter order? What is the difference between 2nd order, 4th order, 10th order etc.. filters?..............................
by Duane Benson
by Aaron Carman
by Aaron Carman
by Aaron Carman