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hai all
Did you tried to implement direct form 2 IIR filter on ADSP-2181 processor ? Or do anyone know how to scale the coefficients ? If yes, How did you solved the problem of coefficients ? see this filter wht i am trying to implement Enter the pass band ripple...0.1 Enter the stop band ripple...40 Enter the pass band freq...1000 Enter the stop band freq...1100 enter the sampling frequency...8000 **************a coefficients******************* Columns 1 through 4 1.00000000000000 3.73094735132357 6.95891002293102 8.61932896241283 Columns 5 through 8 7.93738508378279 5.77588060865060 3.43873153375972 1.71713449461696 Columns 9 through 12 0.72771969127952 0.26526386857069 0.08294964315450 0.02249604137781 Columns 13 through 16 0.00517620631694 0.00102955272352 0.00016536577519 0.00002269647538 Columns 17 through 18 0.00000209429411 0.00000016632254 **************b coefficients***************** Columns 1 through 4 0 0.04634751866435 -0.00000000000000 0.16534056868287 Columns 5 through 8 0.00000000000000 0.17203593191299 0.00000000000000 0.08036843333569 Columns 9 through 12 0.00000000000000 0.01991021498324 0.00000000000000 0.00279806823284 Columns 13 through 16 0.00000000000000 0.00022395186624 0.00000000000000 0.00000951104724 Columns 17 through 18 0.00000000000000 0.00000016632254 Now how to scale them ? Thats the problem. Also in both of the coefficients "a and b" there are 18 coefficients , But the ADSP vol 1 book says the elements should be 1 less in "a" array compared to "b" array. But both are same here. I read from one of the documents tht we need to exclude 1.000000000(AD processor but some other series). Also according the document the elements of "a" should be negated and must be used in the reverse order of appearance. The same thing is true for "b" but there is no negation. I am little bit confused. Plz help me out if possible. Thanx for reply Bye G ________________________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html |
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Re: Digest Number 874
Started by ●May 12, 2004
Reply by ●May 12, 20042004-05-12
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On Wed, 12 May 2004, [iso-8859-1] Girish wrote: > Did you tried to implement direct form 2 IIR filter on > ADSP-2181 processor ? Nope. > Or do anyone know how to scale the coefficients ? With a simple multiply usually. > If yes, How did you solved the > problem of coefficients ? There's two ways. One is to get a book and learn the math. It's not hard, it just takes time. The second way is to get a program that does it for you. For example: http://www.icsi.berkeley.edu/~storn/fiwiz.html Patience, persistence, truth, Dr. mike |
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Reply by ●May 12, 20042004-05-12
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At 08:32 AM 5/12/2004, Mike Rosing wrote: >On Wed, 12 May 2004, [iso-8859-1] Girish wrote: > > > Did you tried to implement direct form 2 IIR filter on > > ADSP-2181 processor ? With a fixed point dsp, especially 16 bit, you should use Direct Form I Do a google search on this for deatils >Nope. > > > Or do anyone know how to scale the coefficients ? > >With a simple multiply usually. > > > If yes, How did you solved the > > problem of coefficients ? > >There's two ways. One is to get a book and learn the >math. It's not hard, it just takes time. The second >way is to get a program that does it for you. For >example: http://www.icsi.berkeley.edu/~storn/fiwiz.html > A really good filter design program is QEDesign from Momentum Data Systems www.mds.com Al Clark Danville Signal Processing, Inc. -------------------------------- comp.dsp conference July 28 - Aug 1, 2004 details at http://www.danvillesignal.com/index.php?id=compdsp email: Who says you can't teach an old dog a new DSP trick? |
