3) Filter Theory

This page goes into more depth about what actually happens with digital filters. This is going to go over my head (mz), but is worth having around, for reference.

Topics

Time-domain Filters are Delays

An example of averaging a data stream as a simple low pass filter.

Specific filters

• Butterworth filter - no gain ripple in pass band and stop band, slow cutoff
• Chebyshev filter(Type I) - no gain ripple in stop band, moderate cutoff
• Chebyshev filter(Type II) - no gain ripple in pass band, moderate cutoff
• Bessel filter - no group delay ripple, no gain ripple in both bands, slow gain cutoff
• Elliptic filter - gain ripple in pass and stop band, fast cutoff
• Optimum "L" filter
• Gaussian filter - no ripple in response to step function
• Hourglass filter
• Raised-cosine filter

FIR and IIR - what does that mean?

Filtering in the Spectral Domain