FIR Cookbook?
in [DSP]
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From: jeff227 on 12 Dec 2006 18:23 Great info, Ron. Thank you for the clarification.
From: Ron N. on 12 Dec 2006 18:38 jeff227 wrote: > >By the way, bandwidth of these filters in not usually defined by some > >number of dB down on the skirt as it is with many analog filters. If the > > >passband spec is +/- n dB, the passband is over when the response is out > > >of spec. The filter is characterized by a passband where it meets some > >spec, a transition band where any response (technically, including a > >peak) is acceptable, and a stopband with some minimum attenuation. > > > >Jerry > > > Yes, I understand, this is true for many applications. > > However, I am using these FIR filters in a linear phase, multi-point > crossover in an audio application. The reason the -6dB point is > significant is because it is the point where, A) HP and LP filter outputs > sum to unity and, B) a HP filter can be directly computed by spectral > inversion of the LP coefficients. And if you look at the code, spectral inversion is how a filter for a given center frequency fc is generated. cos(i * 0 / (fs/2)) means don't invert for a lowpass filter. cos(i * (fs/2)/(fs/2)) means spectrally invert for a highpass filter. fc values in between 0 and fs/2 move the frequency domain rectangle in between a low and high pass to create a bandpass filter, all in the same one line of Basic code. A little terse I admit. IMHO. YMMV. -- Ron N. http://www.nicholson.com/rhn/dsp.html
From: Jack Ace on 13 Dec 2006 04:16 jeff227 ha scritto: > Has anyone come up with a "cookbook" for simple FIR filters similar to > RBJ's IIR cookbook? > > I am looking for audio filters (i.e., mild rolloff, fast compute) using > relatively short FIRs (50 coeffs max). Reason for FIR is that I need > linear phase. Reason for cookbook is that I need to calculate the > coefficients as part of the routine (so the filter will work at different > sample rates). Window-based FIRs would probably be most efficient for > audio purposes. > > I have started compiling bits of code for Window-based FIRs but it would > nice not to re-invent the wheel if a "cookbook" already exists! > > Thank you have a look at "DSP Filter Cookbook " by John Lane et Al. it has a focus on audio application and treats FIR as well as IIR. http://www.amazon.com/DSP-Filter-Cookbook-Electronics/dp/0790612046/sr=1-2/qid=1166000919/ref=sr_1_2/105-0199217-5635669?ie=UTF8&s=books. I never read it... just browsed some page. I hope it could help you. Bye jack
From: Jack Ace on 13 Dec 2006 04:27 I forgot to tell you about the book website http://www.dspaudiocookbook.com/ you can Download DSP Filter Cookbook examples (132k): gargle.zip Table of Contents and a Summary also available. Bye Jack Jack Ace ha scritto: > jeff227 ha scritto: > > > Has anyone come up with a "cookbook" for simple FIR filters similar to > > RBJ's IIR cookbook? > > > > I am looking for audio filters (i.e., mild rolloff, fast compute) using > > relatively short FIRs (50 coeffs max). Reason for FIR is that I need > > linear phase. Reason for cookbook is that I need to calculate the > > coefficients as part of the routine (so the filter will work at different > > sample rates). Window-based FIRs would probably be most efficient for > > audio purposes. > > > > I have started compiling bits of code for Window-based FIRs but it would > > nice not to re-invent the wheel if a "cookbook" already exists! > > > > Thank you > > have a look at "DSP Filter Cookbook " by John Lane et Al. > > it has a focus on audio application and treats FIR as well as IIR. > > http://www.amazon.com/DSP-Filter-Cookbook-Electronics/dp/0790612046/sr=1-2/qid=1166000919/ref=sr_1_2/105-0199217-5635669?ie=UTF8&s=books. > > I never read it... just browsed some page. > I hope it could help you. > > Bye > jack
From: Rune Allnor on 13 Dec 2006 06:21
Jack Ace skrev: > jeff227 ha scritto: > > > Has anyone come up with a "cookbook" for simple FIR filters similar to > > RBJ's IIR cookbook? > > > > I am looking for audio filters (i.e., mild rolloff, fast compute) using > > relatively short FIRs (50 coeffs max). Reason for FIR is that I need > > linear phase. Reason for cookbook is that I need to calculate the > > coefficients as part of the routine (so the filter will work at different > > sample rates). Window-based FIRs would probably be most efficient for > > audio purposes. > > > > I have started compiling bits of code for Window-based FIRs but it would > > nice not to re-invent the wheel if a "cookbook" already exists! > > > > Thank you > > have a look at "DSP Filter Cookbook " by John Lane et Al. > > it has a focus on audio application and treats FIR as well as IIR. > > http://www.amazon.com/DSP-Filter-Cookbook-Electronics/dp/0790612046/sr=1-2/qid=1166000919/ref=sr_1_2/105-0199217-5635669?ie=UTF8&s=books. > > I never read it... just browsed some page. > I hope it could help you. > > Bye > jack Seems about the right size I would expect for a decent filter cookbook -- a couple of hundred pages. Rune |