DeusDingo@gmail.com writes:> [...]Hi whoever-you-are, Stephen and others have nicely attempted to answer your direct questions. I have another suggestion. Don't use terms or concepts you don't understand. You threw a bunch of terminology into your original post, like, I did a little reading around the net and it sounded like the delta function just gives you the poles and that is what I'm seeing, but reading a post on here made it sound like I should have gotten the true impulse response. which makes it clear you either a) don't understand the concepts or b) have poor writing skills. I'm assuming it's a). We all have to learn piece-by-piece, so as soon as you get to something you don't understand, pull out a book, search the net, ask a teacher or colleague, post here, etc., until you've cleared up any doubts. This is just hopeully a helpful piece of advice. -- % Randy Yates % "With time with what you've learned, %% Fuquay-Varina, NC % they'll kiss the ground you walk %%% 919-577-9882 % upon." %%%% <yates@ieee.org> % '21st Century Man', *Time*, ELO http://www.digitalsignallabs.com
Is this a strange Freq response for an FIR filter?
Started by ●January 29, 2008
Reply by ●January 30, 20082008-01-30
Reply by ●January 30, 20082008-01-30
On Jan 29, 8:29�pm, "SteveSmith" <Steve.Smi...@SpectrumSDI.com> wrote:> You have two simple problems here: too short of an FFT, and not controlling > your graphing program. > > Since you start with a 63 point impulse response, your program is taking > an N=64 point FFT. �This produces a frequency domain with 33 samples > between DC and one-half of the sampling rate. �This makes the frequency > domain samples 125 Hz apart, as you found. �Also, it appears that your > graphing program is incorrectly showing a value of zero between these > samples, giving the impression of peaks. � > > To correct this, pad the 63 points in the impulse response with a bunch of > zeros, and take a longer FFT. �Say, add 1985 samples and use an FFT length > of 2048. �Your problem will go away. You are very close and on exactly the > right track. Here is a reference: > > http://www.dspguide.com/ch9/2.htm > > Regards, > Stevethanks steve, you are probably the only one who could read through my poor use of the terminology to tell me what was going on. I did the zero padding and it worked like a charm, you have no idea how much time this saved me. I'm definately going to have to read up on this again so I can remember all this basic signal stuff again.
Reply by ●January 30, 20082008-01-30
On Jan 30, 4:30�am, Randy Yates <ya...@ieee.org> wrote:> DeusDi...@gmail.com writes: > > [...] > > Hi whoever-you-are, > > Stephen and others have nicely attempted to answer your direct > questions. I have another suggestion. > > Don't use terms or concepts you don't understand. You threw a bunch of > terminology into your original post, like, > > � I did a little reading around the net and it sounded like the delta > � function just gives you the poles and that is what I'm seeing, but > � reading a post on here made it sound like I should have gotten the > � true impulse response. � > > which makes it clear you either a) don't understand the concepts or b) > have poor writing skills. I'm assuming it's a). > > We all have to learn piece-by-piece, so as soon as you get to something > you don't understand, pull out a book, search the net, ask a teacher or > colleague, post here, etc., until you've cleared up any doubts. > > This is just hopeully a helpful piece of advice. > -- > % �Randy Yates � � � � � � � � �% "With time with what you've learned, > %% Fuquay-Varina, NC � � � � � �% �they'll kiss the ground you walk > %%% 919-577-9882 � � � � � � � �% �upon." > %%%% <ya...@ieee.org> � � � � � % '21st Century Man', *Time*, ELOhttp://www.digitalsignallabs.comwell it's part a and part b. Seeing as I haven't done this kind of thing in a while my terminology abilities (which aren't that good to begin with) were real shaky. but I did go online, read my notes, look in some text books, etc but I was so busy looking for something in particular that I didn't pick back up the terms that I used to know. but thanks to everyone for their patience and understanding, especially fred who I kind of snapped at. and thanks especially to steve for figuring out exacly what my problem was (outside of poor writing skills and overall rustiness on the topic).
