In Reply to: All FIR filters are fatally flawed. posted by jmlpartners on February 10, 2009 at 13:08:04:
Get yourself a good text book on Digital Signal Processing and study it. After you have done so, then you may have a good idea of what is wrong with your post. A reference is listed below, but you may need to learn some math before you can understand it.
I will point out one thing. If the signal were 7 octaves below the Nyquist frequency, then there would be 128 cycles of ringing for each cycle of your "signal". One cycle of your signal occupies about 50 horizontal pixels in your photos. So any ringing from a filter that cuts off near the Nyquist frequency would not be visible in your pictures.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
- http://www.amazon.com/Discrete-Time-Signal-Processing-2nd-Prentice-Hall/dp/0137549202/ref=sr_1_1?ie=UTF8&s=books&qid=1234322188&sr=1-1 (Open in New Window)
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Follow Ups
- RE: All FIR filters are fatally flawed. - Tony Lauck 19:24:38 02/10/09 (18)
- RE: All FIR filters are fatally flawed. - jmlpartners 08:34:11 02/11/09 (17)
- RE: All FIR filters are fatally flawed. - Tony Lauck 10:18:25 02/11/09 (16)
- RE: All FIR filters are fatally flawed. - jmlpartners 12:14:55 02/11/09 (7)
- RE: All FIR filters are fatally flawed. - Todd Krieger 14:48:04 02/11/09 (0)
- RE: All FIR filters are fatally flawed. - Tony Lauck 13:37:27 02/11/09 (5)
- RE: All FIR filters are fatally flawed. - jmlpartners 20:38:10 02/11/09 (4)
- RE: All FIR filters are fatally flawed. - Tony Lauck 08:59:09 02/12/09 (0)
- You STILL don't get it - dwk 08:18:33 02/12/09 (2)
- No, I DO get it. - jmlpartners 10:16:03 02/12/09 (1)
- RE: No, I DO get it. - Tony Lauck 10:41:13 02/12/09 (0)
- Question about "upsampling" - Slider 11:38:31 02/11/09 (7)
- RE: Question about "upsampling" - Todd Krieger 14:59:38 02/11/09 (0)
- RE: Question about "upsampling" - Tony Lauck 11:57:03 02/11/09 (5)
- No brickwall filter then? - Slider 12:11:50 02/12/09 (4)
- No Free Lunch! - Charles Hansen 20:30:32 02/12/09 (0)
- RE: No brickwall filter then? - Tony Lauck 13:52:34 02/12/09 (2)
- So, is that a yes? - Slider 23:56:53 02/12/09 (1)
- One of the few posts by Ted that is wrong. - Charles Hansen 10:42:34 02/13/09 (0)