Lan wrote in news:50650000000800000060A30000-1042324653000
@exchange.ni.com:
> Hi,
> I have a simple vi that reads analog signals, which have to be
> filtered. In Labview (I'm using version 7.0, not that it matters),
> there are a many different types of low-pass filters (Chebyshev,
> Butterworth, etc.) and limited to my knowledge right now, they all
> seem to be somewhat similar. I tried to find their differences and the
> pros and cons of each filters but to my dissapointment, i couldnt. Can
> somebody pls let me know what are the pros and cons of the filters, or
> at least direct me to a webpage that contains this information?
> Thanks, it is highly appreciated!
>
Butterworth filters are maximally flat in the pass band, and roll off more
slowly in the reject region. Use this filter if constant gain in your
passband is a must.
Chebychev filters fall like a hot rock in the reject region, at the expense
of ripple in the pass band. Use this if you need a rapid descent into the
reject region.
Bessel filters are linear phase, equivalent to a simple time delay, thus
you have a time delay in the output, but no phase distortion. Use this
filter if you cannot tolerate phase distortion.
If you need more description on other types, just list the names, and I'll
try to help.
Also, in general, its useful for further analysis if you pass ALL your
channels through the same filters
Scott
