On Sat, 21 Mar 2009 14:02:09 -0500, "cfy30" <cfy30@yahoo.com> wrote: >Hi all, > >Consider a FIR filter with coefficients [1 2 3 2 1] > >I know the group delay is 2, (5-1)/2. Can anyone tell how to deduce the >group delay of 2 without going through the d(theta)/d(omega) mathematics? >Is there an easy way to find the group delay? > > >cfy30 Hi cfy30, your question has, what I consider to be, a fairly deep (significant underlying) meaning. I like Tim's "hand waving" explanation. Sometimes in their algebraic derivations of z-domain transfer functions, some authors arrive at a transfer function equation of some network whose impulse response begins before an impulse input is applied. They call such networks "acausal". Then they say something like: "To make the network causal, we add a delay to the network." That kind of explanation always irritates me because how can they add a delay to a network when that network cannot exist in our physical universe? Ha ha. By the way, you asked for ways to compute "group delay of without going through the d(theta)/d(omega) mathematics". You might have a look at: http://www.dsprelated.com/showarticle/69.php The above scheme avoids the "d(theta)/d(omega) mathematics" but still has plenty of other mathematics. See Ya', [-Rick-]

0 |

3/24/2009 12:33:11 PM

Hello all, I'm working with 21161N EZ-KIT in a active noise control system... I'm looking for a way to measuring the time of my filter (FIR) and my algorithm takes me !!! the clock of my processor is 100Mhz... and a cycles is 10ns... I put a counter that calculated 1340 lines executed... can I calculate 1340 X 10ns ???? and how can I calculate the group delay in my filters (FIR) !?? thank's everybody !! henrique On 3 Nov, 14:50, "hbarcellos" <henrique_barcel...@hotmail.com> wrote: > and how can I calculate the group delay in my filters (FIR) !?? You mention 'active noise control' so I suppose you don't have nice symmetric FIRs. The general algorithm is outlined on pages 25-27 of McClellan & al: Computer-Based Excercises for Signal Processing using Matlab 5 Pearson, 1998. A very useful book, if you can find it. Mentioning version 5 of matlab in the title is just about the most stupid thing ever done in DSP - the projects work with any version of matlab. With a couple of chapters added on stuff that presently is included in the SP toolbox (mainly filters design functions and some correlation functions), this would have been an all-time classic. Rune On Nov 3, 8:50=A0am, "hbarcellos" <henrique_barcel...@hotmail.com> wrote: > > ... how can I calculate the group delay in my filters (FIR) !?? > i don't get it. is it that you want to calculate the group delay...

I am trying to calculate group delay of a FIR filter on PC. I use Matlab but I am confused with its algorithm. Basically the Matlab algorithm says this, group_delay(f) = Fourier transform of {n * h[n]} where h[n] is impulse response of the filter. But the Fourier transform of h[n]*n is the differentiation of H(w) with respect to w and not differentiation of phase of H(w) with respect to w, i.e. h[n]*n <------> j * d(H(w))/dw Am I missing something? What would people normally do to calculate group delay of a FIR filter on a PC? Thanks. cykhung@hotmail.com wrote: > I am trying t...

The Matlab command 'grpdelay' is restricted to digital filters only. Does there exist some counterpart to 'grpdelay' that operates in the analog domain? Some Matlab commands have separate versions for the analog and digital domains, and I wonder why 'grpdelay' does not. For example, the 'butter' command to generate Butterworth filter coefficients has digital and analog versions. The analog version is useful for understanding the stand-alone characteristics of a proposed filter, i.e., the characteristics that are independent of a particular sampled data record. ...

Hi. I note that a suitably designed FIR filter with N coefficients can have a time-delay of N/2 (or is it (N-1)/2?). I'm designing low pass filters by the window method. In my application I'm taking whole sample files and filtering after the fact. It is very important for me to be able to say for any sample in my filtered sample what the original time of that sample was in the original file. Hence it looks sensible for me to reinterpret the coefficients of my FIR filter so that when producing an output sample y[i], that my coefficients are applied to samples at times x[i-N/2] to x[i+N/...

Has anyone implemented a function to find the group delay (the time between= the filter's initial response and its peak response)of the different digit= al filters in LabVIEW?<br><br>I need to track the arrival of a certain part= of a signal. I know approx. when it is to arrive, however locating it gets= complicated due to the variable delay caused by the necessary filtering (d= elay depends on the frequencies, filter order, type etc.) .<br><br>I see th= at MatLAB / MatWorks has a group delay function, but perhaps someone has ma= de a G equivalent? <br><br>The digital filter design toolkit is said to hav= e analysis tools that can give you the group delay...but I'm not sure if th= at could be used to find the delay in any case programmatically? Even if it= can I'm a bit reluctant to buy the toolkit just for that functionality...<= br><br>I though I had solved it when I found a description of how to calcul= ate the delay of a Butterworth filter (at least) on: http://www.mathcad.com= /Library/LibraryContent/MathML/group_b.htm<br><br>The results are in the ri= ght ballpark...but sometimes it fails by more than 5 microseconds and that'= s not good enough for my application (could be an incorrect implementation = off course). <br><br>If I use correlation to find the delay I get extremely= good results, however that will not be robust enough (there could be other= strong features, e.g. due...

Dear all, My task is to implement a very narrow high pass filter to remove a DC offset of a signal. So the cut off frequency of the filter is very low. The filter must be linear phase. A first implementation was made using a double cascaded moving average filter. The filter seems to do its job very well. Unfortunately the group delay of the filter is too large. I have read some articles on multi rate filtering. Although I the feeling I could use this to find a filter with a shorter group delay most articles point out that multi rate filtering is not used to lessen the group delay. Let's say I have a signal X at sample rate Fs. 1. I split the signal in two new signals Xlowpass and Xhighpass by applying a low and high pass filter with a cutoff of about Fs/4. 2. Because Xlowpass does not contain any frequencies above Fs/4 I can downsample the signal Xlowpass without aliasing in a resulting signal Xdown. 3. Now I can find a low pass filter to do the original DC filtering at this lower rate on the signal Xdown. The DC filter will have to be less narrow resulting in a lower group delay. 4. After the DC filtering I can upsample the signal Xdown and add the high frequency part Xhighpass to get the final signal but now DC filtered. Maybe someone can point out why this will not work. An alternative idea to lessen the group delay of the DC filter would also be greatly appreciated. Regards, Dinne Dinne wrote: > Dear all, > > My task is to implement a very...

Is there a simple expression for the group delay of a CIC filter stage in terms of the differential delay (M) and the rate change R? -- Randy Yates % "Watching all the days go by... Digital Signal Labs % Who are you and who am I?" mailto://yates@ieee.org % 'Mission (A World Record)', http://www.digitalsignallabs.com % *A New World Record*, ELO On Fri, 18 Jun 2010 11:21:37 -0400, Randy Yates <yates@ieee.org> wrote: >Is there a simple expression for the group delay of a CIC filter stage >in terms of the ...

I want to make bandpass filter from lowpass filter prototype. first i made lowpass filter and frequency translated using cosine function and i saw the freq. response of translated coefficient. but it differs from lowpass filter response. b = firceqrip(368, 4.3/(122.88/2), [0.1, 0.0018], 'slope', 0); fvtool(b); n=0:length(b)-1; cos_b = b.*(cos(((3*pi)/8)*n)); fvtool(cos_b) > lowpass filter : attenuation is 55dB > bandpass fitler : attenuation is about 50dB and filter shape is different, especially filter edge part. am i wrong in implement bandpass filter fr...

Hi, The fdatool in matlab usually designs a real equiripple filter with a group delay (N-1)/2 or N/2, where N is filter length. Given desired magnitude response, to design a linear phase filter with a prescribed group delay, will the optimum filter be real coefficient and symmetric? Thanks. ZedToe "ZedToe" <acoustictech_zhangtao@yahoo.com.sg> wrote in message news:7c4bf533.0401070850.53b25746@posting.google.com... > Hi, > > The fdatool in matlab usually designs a real equiripple filter with a > group delay (N-1)/2 or N/2, where N is filter length. > > Gi...

Hi, As far as I know, the group delay of a all-pass filters always is a positive number. Is there a all-pass filters which group delay is negative？ Alan On 9/7/2011 10:56 PM, zaitax wrote: > Hi, > As far as I know, the group delay of a all-pass filters always is a > positive number. Is there a all-pass filters which group delay is > negative？ > Alan Group delay measures the time between when energy (or information) goes in and when it comes out. Your question amounts to asking if energy can come out before it went in. I'm rooting for you to be able to answer that on your own. Jerry -- Engineering is the art of making what you want from things you can get. >On 9/7/2011 10:56 PM, zaitax wrote: >> Hi, >> As far as I know, the group delay of a all-pass filters always is a >> positive number. Is there a all-pass filters which group delay is >> negative？ >> Alan > >Group delay measures the time between when energy (or information) goes >in and when it comes out. Your question amounts to asking if energy can >come out before it went in. I'm rooting for you to be able to answer >that on your own. > >Jerry >-- >Engineering is the art of making what you want from things you can get. > There are some negative group delay filter, Such as, peakingEQ has a negative group delay peak when the gain is negative. Jerry Avins <jya@ieee.org> wrote: > On 9/7/2011 10:56 PM, zaitax wrote: ...

Hi, all: is there a specific function for continuous system to analyze group delay? i tried grpdelay function, but it seems to be for digital filter and gives wrong result for a continous system. Thanks. ...

I want to make bandpass filter from lowpass filter prototype. first i made lowpass filter and frequency translated using cosine function and i saw the freq. response of translated coefficient. but it differs from lowpass filter response. b = firceqrip(368, 4.3/(122.88/2), [0.1, 0.0018], 'slope', 0); fvtool(b); n=0:length(b)-1; cos_b = b.*(cos(((3*pi)/8)*n)); fvtool(cos_b) > lowpass filter : attenuation is 55dB > bandpass fitler : attenuation is about 50dB and filter shape is different, especially filter edge part. am i wrong in implement bandpass filter fr...

hallo to anyone. i'm trying to apply a delay filter to an input signal. I'd like that this delay is implemented with an upsampling, because i'm talking about a fractionary delay. Is it possible to only upsample the filter impulsive response and not the whole input signal? this is my Matlab Code fc=100; %sample frequency of input signal t=0:2*pi/(fc-1):2*pi; x=sin(t); %input signal subplot(121); stem(t,x); title('Original Signal'); n_points=length(x); tau=3.45; %delay (samples) up_factor=10; %upsampling factor tau_up=round(tau*up_factor); NFFT=2^nextpow2(n_points*up_factor); %------ anti imaging filter---------% h_imaging=up_factor*fir1(32,1/up_factor,blackman(32+1)); H_IMAGING=fft(h_imaging,NFFT); h_delay=[zeros(1,tau_up) 1]; H_DELAY = fft(h_delay,NFFT); X = fft(x,NFFT); OUT1 = H_DELAY.*X.*H_IMAGING; out1=real(ifft(OUT1,NFFT)); out=downsample(out1,up_factor); subplot(122); stem(t,out(1:n_points)); title('Signal with delay'); Sorry for my bad english aenima1891 schrieb: hello, the impulse response of a delaye filtered signal is: y(t)=conv(x(t-tau),h(t)) (1) So its Fourier Transform is Y(f)=X(f)*exp(-j*2*pi*tau*f)*H(f) (2) So the delay leads to a multiplication in the frequency domain with a complex phase term and it doesn't matter if you delay the filtered version or the original version since the order of multiplication is exchangable. But I am wondering why you want to upsample the signal at all, when you downsample it after t...

I am new to digital filters. I am trying to understand them. I have gone through the internet and found the design of a simple low pass filter. It can be implemented digitally by an FIR filter (which is a simple averaging filter). The example that I found is something like this: Suppose x[n] is digital bit sequence. So the averaging filter (low pass) would be: 0.5 * (x[n] + x[n-1]) where x[n-1] represents x[n] with 1 unit of delay. Now another averaging filter ((low pass)) would be: 0.25 * (x[n] + x[n-1] + x[n-2] + x[n-3]) ---> 4 units of delay used here As you all know the most common term related to any filter (in the analog domain) is the cutoff frequency. Now my question is: (1) What is the OR Is there any relation between the number of delays used and the cutoff frequency? Meaning, if you increase/decrease the number of delays, how will it affect the cutoff frequency of that filter? (2) What is the OR Is there any relation between the co-efficient used and the cutoff frequency? Meaning, if you increase/decrease the value of the co-efficient, how will it affect the cutoff frequency of that filter? Thank you. On 7 Okt, 13:49, "ronycsdu" <ronyc...@yahoo.com> wrote: > I am new to digital filters. I am trying to understand them. I have gone > through the internet and found the design of a simple low pass filter. It > can be implemented digitally by an FIR filter (which is a simple averagin= g > filter). The example that I found is so...

Hi all, I want to design a filter (invertable if possible) that has the minimu amount of group delay and captures the maximum amount of variance given particular data set. I'm thinking something very similiar to the Karhunen&Loeve (KL) transform aka the 'singular spectrum' and also 500 other names... It's just principl coponent analysis of the trjacectory matrix and retaining the first fe significant eigenvectors. I've design a very simple direct-form type II transposed filter which is simple oscillator [x(i)-mean(x(i-t:i-1))], or [1 -ones(t,1)/t] which ha very fa...

Dear All, I looking for a self made FIR Digital Filter using Simulink. I would like to know if there is any freely available webinars or links to learn "How to realize a FIR-Digital filter (Low Pass, High Pass & Band-Pass FIR digital filters) in simulink". I know there is a Digital filter block diagram but I want to know If I can design my own Filter in Simulink. If any one has idea then I will be glad to know. Thanking you, With Regards, Prashant "Prashant Sandhi" wrote in message <jg8obe$17l$1@newscl01ah.mathworks.com>... > Dear ...

Hi all I'm trying to find design methods or literature for low/minimum group delay IIR filters. I'm a bit unsure about what will be the correct term for this kind of filters. But a typically linear-phase FIR has a group delay of 1/2 the filter length. This kind of delay will often be too much since I'm working with motion capture (MoCap) sensors that typically have sampling rates around 100 Hz. I'm guessing that IIR filters can give me more powerful low group-delay filters than FIR. But the typcal filter design tool in MATLAB does not optimize for low group delay. So my question is: Are there design methods that enable one to minimize the group delay? Let say the best filter with a group delay around 2, 1 or 0 samples? A flat phase is also a wish but not necessarily at the same time. Thank you for any advice you may have. On 8/25/11 11:21 AM, staldor wrote: > Hi all > > I'm trying to find design methods or literature for low/minimum group delay > IIR filters. > > I'm a bit unsure about what will be the correct term for this kind of > filters. But a typically linear-phase FIR has a group delay of 1/2 the > filter length. This kind of delay will often be too much since I'm working > with motion capture (MoCap) sensors that typically have sampling rates > around 100 Hz. > > I'm guessing that IIR filters can give me more powerful low group-delay > filters than FIR. But the typcal filter design tool in...

I've pulled a DSP Group Teak Lite DSP development board out of the bin at work. It's about 3-4 years old. Their web site asks you to login before you can look at docs an support S/W etc. Does anyone have an old support login for this site? Cheers, Alfie. ...

hallo to everyone i'm trying to implement a digital filter which is a pure delay. is this code right? h=fir1(delay*2, 0.999, blackman(2*delay+1)); I use this code because a fir filter give to me a delay equal to half of filter order. fir1 function seems to not accept 1 as second parameter. why? Is there any other simpler code ? (sorry for my english) On Oct 6, 6:36=A0am, "aenima1891" <aenima1...@gmail.com> wrote: > hallo to everyone > i'm trying to implement a digital filter which is a pure delay. > is this code right? > > h=3Dfir1(delay*2, 0.999, blackman(2*delay+1)); > > I use this code because a fir filter give to me a delay equal to half > of filter order. > fir1 function seems to not accept 1 as second parameter. why? > > Is there any other simpler code ? > > (sorry for my english) How about using a simple delay line? John >On Oct 6, 6:36=A0am, "aenima1891" <aenima1...@gmail.com> wrote: >> hallo to everyone >> i'm trying to implement a digital filter which is a pure delay. >> is this code right? >> >> h=3Dfir1(delay*2, 0.999, blackman(2*delay+1)); >> >> I use this code because a fir filter give to me a delay equal to half >> of filter order. >> fir1 function seems to not accept 1 as second parameter. why? >> >> Is there any other simpler code ? >> >> (sorry for my english) > >How about using a si...

Dear all this is my homework, I should determine the delay of this symmetric FIR filter whose length is 3. y[n]=x[n]+x[n-1]+x[n-2]. The answer in the manual solutions is 1. I am confused. In my view, clearly h[0]=1, h(1)=1, h(2)=0, otherwise =zero and it's delay must be two. I guess that the answer is 1 because the filter is symmetric so that h[k]=h[M-k-1] (M=3 is the length of the filter). So delay is only (M-1)/2 if M is odd. Using this thinking, I can find the same answers as in the solution manuals. But indeed I am not satisfied with this explaination and would like to ask you al...

I have a report that uses a query as the recordsource. One field in the query is called Header which can be either Approved, Received, Not Taken, Closed Out. On the report footer - I total each of these by txtTotalApproves = Sum(IIF(Header="Approved",1,0)). Then I reference these in the report header as a summary page at the TOP of the report. So this works - but I want the detail lines of a group to only include header types of Closed Out or Not Taken. I know I could create a subreport, but can a group be filtered somehow? I tried entering an expression in the grouping : IIF(Header="Not Taken" or Header="Closed Out",Header), but that still gave me all status. Thanks, Brian In Report Design Mode, modify the "Record Source" property and then click on the elipses "...". In there, modify the query to filter your data as required. Dominic Vella "BerkshireGuy" <berkshireguy2005-commerical@yahoo.com> wrote in message news:a2f6daa6-340a-4720-9c05-dd8b0d075dcf@m34g2000hsb.googlegroups.com... >I have a report that uses a query as the recordsource. > > One field in the query is called Header which can be either Approved, > Received, Not Taken, Closed Out. > > On the report footer - I total each of these by > > txtTotalApproves = Sum(IIF(Header="Approved",1,0)). Then I reference > these in the report header as a summary page at the TOP of the > report. > > So...

Hi, I am trying to find a way to implement a FIR filter which can give allpass filter with quadratic phase response. The transfer function I am trying to implement is : H = exp( j * alpha * w^2 ). Can some one suggest what is best filter design approach that can be used to find the filter cofficients. Most of the filter design methods concentrate on the amplitude response and linear phase. Thanks sunil skhatana wrote: > Hi, > > I am trying to find a way to implement a FIR filter which can give > allpass filter with quadratic phase response. > > The transfer function I am trying to implement is : > > H = exp( j * alpha * w^2 ). > > Can some one suggest what is best filter design approach that can be used > to find the filter cofficients. Most of the filter design methods > concentrate on the amplitude response and linear phase. You probably want a Hilbert transformer. The length of your filter will depend on the bandwidth and your tolerance for in-band ripple. Jerry -- Engineering is the art of making what you want from things you can get. ����������������������������������������������������������������������� On Mon, 08 Jun 2009 14:27:17 -0500, skhatana wrote: > Hi, > > I am trying to find a way to implement a FIR filter which can give > allpass filter with quadratic phase response. > > The transfer function I am trying to implement is : > > H = exp( j * alpha * w^2 ). > > Can some...

I need to design a butterworth approximated low pass, high pass, band pass, band stop filter characteristics.This i did using DFT technique which is a very heavy algorithm.So My question is how to design the FIR for my requirement.So can anybody help in how to proceed... Thank you :-) With Regards, SRS On Sep 5, 9:56 am, SRS <sitaram...@gmail.com> wrote: > I need to design a butterworth approximated low pass, high pass, band > pass, band stop filter characteristics.This i did using DFT technique > which is a very heavy algorithm.So My question is how to design the > FIR for my requirement.So can anybody help in how to proceed... > Thank you :-) > > With Regards, > SRS A recent article: Butterworth Window for Power Spectral Density Estimation Tae Hyun Yoon, and Eon Kyeong Joo, ETRI Journal, vol.31, no.3, June 2009, pp. 292-297. available from: http://etrij.etri.re.kr/Cyber/servlet/BrowseAbstract?vol=31&num=3&pg=292 gives an approximate Butterworth window approach that can be applied to FIR filters through the window based FIR design approach. Dale B. Dalrymple On 9/5/2009 9:56 AM, SRS wrote: > I need to design a butterworth approximated low pass, high pass, band > pass, band stop filter characteristics.This i did using DFT technique > which is a very heavy algorithm.So My question is how to design the > FIR for my requirement.So can anybody help in how to proceed... > Thank you :-) > > With Regards, ...

Hello World, i work with a dsp and programmed a adaptiv filter for it. i would like to compare the results from the LMS on the DSP, with the optimal filter coefficients from the wiener-filter. the optimal filter weights = wiener solution you get if you use this w = p * R^-1 in words optimal filter coefficient vector = crosscorrelationvektor * inverse autocorrelation everything on the dsp works fine but i lack the mathematics to calculate the wiener optimal filter settings for a given FIR Filter length of n=8. Goal I would like to get 8 nummbers = that would be the filter coefficients ...

Text is available under the Creative Commons Attribution-ShareAlike License ;additional terms may apply. By using this site, you agree to the ...

... you do that” action too so it bought the recently launched app Masquerade (stylized as MSQRD) to instantly have access to its own selfie filter ...

If you're a billion-dollar company targeting millennials and you're not investing in a sponsored Snapchat filter, you're already late to the ...

... Reader Chris Ruberg , digital marketing specialist at OneCommand , shared these screenshots with SocialTimes, displaying the ability to filter ...

Filteract Enlight Instagram Get selective with your photo filters in Filteract is a story by AppAdvice.com AppAdvice - iPhone, iPad, iPod, ...

... not much left for them to improve on besides maybe not having so many of those (admittedly safe) carbon flakes getting through the filter. So, ...

In a strategic move against Snapchat, the world's largest social network buys a popular app that lets users slap silly masks and effects on their ...

A line of weather radios that can overheat and post a fire hazard are among this week's recalled products. Others include mugs that have been ...

... bit more cartoon-like now that the social media company has acquired selfie-altering startup Masquerade Technologies. The Snapchat-like filter ...

... even more so in these polarizing times. That is why Bumble, the dating app from Tinder co-founder Whitney Wolfe, is offering political filters ...

Resources last updated: 3/29/2016 10:30:05 PM