On Wed, 26 Mar 2008 04:51:21 -0700 (PDT), Andor <andor.bariska@gmail.com> wrote: >On 25 Mrz., 07:23, "bharat pathak" <bha...@arithos.com> wrote: >> Hi, >> >> � In the book "DSP a practical approach" 2nd Ed by Ifeachor, Jervis >> � it is mentioned that group delay for type 3 and type 4 LPFIR filter >> � is given by >> >> � Tp = T*(N-1-pi)/2; eq 7.4b page 348 >> >> � Is it correct to have pi inside the brackets for group delay >> � calculation? > >That pi is definitely in the wrong place in that equation. Perhaps it >is missing from another equation in the book? :-) Hi Andor, I agree. The "-pi" characters should not be there. It's very difficult to eliminate all typographical errors in a textbook. Regards, [-Rick-]

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3/26/2008 9:29:10 PM

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. ...

I would like to know if I can predict what the group delay of a CIC filter is. I have an agressive FIR BPF where the sample rate is 2000 x the filter bandwidth. The group delay is longer than I would like it to be. Could a CIC filter offer a lower group delay? I'll need to interpolate back to the original sample rate, so I need to take that into consideration as part of the answer. Thanks, in advance. Jim jim_nospam_beasley@yahoo.com wrote: > I would like to know if I can predict what the group delay of a CIC > filter is. What is a CIC filter? Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein "Bob Cain" <arcane@arcanemethods.com> wrote in message news:dii59h19o4@enews4.newsguy.com... > > jim_nospam_beasley@yahoo.com wrote: >> I would like to know if I can predict what the group delay of a CIC >> filter is. http://www.google.com/search?hl=en&q=%22cic+filter%22+%22group+delay%22 > > What is a CIC filter? > http://www.google.com/search?hl=en&q=cic+filter > > Bob > -- > > "Things should be described as simply as possible, but no simpler." > > A. Einstein Simple enough, Bob? ;-) Cheers, Syms. <jim_nospam_beasley@yahoo.com> wrote in message news:1129092761.120373.45800@z14g2000cwz.googlegroups.com... >I would like to know if...

It is known, that non-uniformity of the frequency response of the channel influences level of ISI. And what kind of distortions is characteristic for non-uniform group delay time? On Feb 5, 3:08=A0am, "alex65111" <alex65...@list.ru> wrote: > It is known, that non-uniformity of the frequency response of the channel > influences level of ISI. And what kind of distortions is characteristic f= or > non-uniform group delay time? A non-constant group delay vs frequency (non-linear phase vs frequency) distorts the pulse shape. This causes ISI. John >On Feb 5, 3:08=A0am, "alex65111" <alex65...@list.ru> wrote: >> It is known, that non-uniformity of the frequency response of the channel >> influences level of ISI. And what kind of distortions is characteristic f= >or >> non-uniform group delay time? > >A non-constant group delay vs frequency (non-linear phase vs >frequency) distorts the pulse shape. This causes ISI. > >John > As on level of pulsations group delay it is possible to estimate effective duration of the impulse response? On Feb 5, 3:47=A0pm, "alex65111" <alex65...@list.ru> wrote: > >On Feb 5, 3:08=3DA0am, "alex65111" <alex65...@list.ru> wrote: > >> It is known, that non-uniformity of the frequency response of the > channel > >> influences level of ISI. And what kind of distortions is characteristi= c > f=3D > >or >...

Hi, Matlab has a function called iirgrpdelay which helps in designing iir group delay equalizer filters. Any idea as to how this function can be re-written for people who are not using matlab? Bharat Pathak "bharat pathak" <bharat@arithos.com> wrote in message news:fs-dnX5z64XJUBTanZ2dnUVZ_hCdnZ2d@giganews.com... > Hi, > > Matlab has a function called iirgrpdelay which helps > in designing iir group delay equalizer filters. This is a shamanistic optimization which tries to match the group delay profile by the brute force tweaking of an allpass function. > Any idea as to how this function can be re-written > for people who are not using matlab? I am glad to see that there are still some real people who dare to live without MatLab. Vladimir Vassilevsky DSP and Mixed Signal Consultant www.abvolt.com On Jan 13, 3:35 am, "bharat pathak" <bha...@arithos.com> wrote: > > Matlab has a function called iirgrpdelay which helps > in designing iir group delay equalizer filters. > > Any idea as to how this function can be re-written > for people who are not using matlab? > i can only suggest to start with the MATLAB source code (i might have an old copy) for iirgrpdelay() and all functions that it depends on, and translate to C or whatever language you like. remember the stupid MATLAB indexing origin property. you might be adjusting some indices by 1. you know, probably everyone he...

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. ...

Anyone noticed that google groups is not updating SAS-L ? Today the newest item is dated 2 days ago. R That's true, very unexpected delays both for new posts and also for replies. Hope will be fixed soon. On Oct 29, 12:33=A0am, Akshaya <akshaya.nathil...@gmail.com> wrote: > That's true, very unexpected delays both for new posts and also for > replies. Hope will be fixed soon. Seems to be back to normal now. R ...

From a recent discussion here: > >if i could generate some coefficents that had a 'negative' group delay for > >a period of time, would you think that 'phase cloning' was new and > >intersting?? > > A time machine would be pretty revolutionary, yes. > > Negative group delay means that the output appears before the input > arrives. Fascinating concept, isn't it? I was curious enough to dig into the topic for a while and write up what I found out. You can read about it here: http://www.dsprelated.com/showarticle/54.php Regards, Andor On Mar 7, 5:18=A0pm, Andor <andor.bari...@gmail.com> wrote: > From a recent discussion here: > > > >if i could generate some coefficents that had a 'negative' group delay = for > > >a period of time, would you think that 'phase cloning' was new and > > >intersting?? > > > A time machine would be pretty revolutionary, yes. > > > Negative group delay means that the output appears before the input > > arrives. > > Fascinating concept, isn't it? I was curious enough to dig into the > topic for a while and write up what I found out. You can read about it > here: > > http://www.dsprelated.com/showarticle/54.php > > Regards, > Andor Hello Andor, Very well written article. Hopefully this will put a lot of the seeming paradoxes associated with group delay to bed. The previous threads must h...

I designed an algorithm to compute signal delay through an RF channel. I first verified the algorithm using a known IIR model. I managed to get groupdelay of this IIR spot on compared to that given by Matlab function grpdelay(num,den). The algorithm is based on sending frequency sweep chirp signal followed by fft then conversion of phase to groupdelay using the derivative of negative angular phase with respect to angular frequency. The algorithm has been released and is working well. I am now asked if I could apply it to the case when the available test signal is only single tone instead of frequency sweep. I tested my same algorithm on single tone. All looks ok but with a mystery factor of 2 needed to get IIR model groupdelay match that of matlab. I mean if I multiply the computed groupdelay based on fft by 2 then it gets correct with a small margin of error. Any idea what this factor of 2 might be. In both cases I use real only chirp signal or real only single tone and the fft is complex. Processing is identical throughout the algorithm for both cases in every step. Regards Kadhiem kaz <37480@dsprelated> wrote: > I designed an algorithm to compute signal delay through an RF channel. > I first verified the algorithm using a known IIR model. I managed to get > groupdelay of this IIR spot on compared to that given by Matlab function > grpdelay(num,den). The algorithm is based on sending frequency...

Dear all I not very familiar with filter design in Matlab and I am probably missin something when it comes to "group delay". My problem comes as follows. From what I have understood, if I have a filter such that its group dela response (plotted with grpdelay[b,a] in matlab with a,b the filte coefficients) provides 17 as the group delay (in samples) at f=0.1 (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequenc being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through th filter I should get at the output the same sinusoid (assuming gain is one delayed by...

Hi, I am seeing some negative group delay at 1000, 2000, 3000, 4000, 5000 Hz. The example filter listed below with matlab/octave code. any clue why this is happening? interesting part is when I feed 1000 hz sine wave sampled at 10000 hz I don't see the behaviour of negative group delay. Regards Bharat %---------------------------------------------------------------- clear; close all; h1 = [10 9 8 7 6 5 4 3 2 1]/55; Fs = 10000; [gd, f] = grpdelay(h1, 1, 8192, Fs); figure; clf; plot(f, gd); On Mar 12, 5:58 pm, "bharat pathak" <bha...@arithos.com> wrote: > Hi, > > I am seeing some negative group delay at > 1000, 2000, 3000, 4000, 5000 Hz. The example > filter listed below with matlab/octave code. > > any clue why this is happening? interesting > part is when I feed 1000 hz sine wave sampled > at 10000 hz I don't see the behaviour of > negative group delay. Individual sine waves don't experience group delay, they experience phase delay. -- Oli On Mar 12, 11:04 am, Oli Charlesworth <ca...@olifilth.co.uk> wrote: > On Mar 12, 5:58 pm, "bharat pathak" <bha...@arithos.com> wrote: > > > Hi, > > > I am seeing some negative group delay at > > 1000, 2000, 3000, 4000, 5000 Hz. The example > > filter listed below with matlab/octave code. > > > any clue why this is happening? interesting >...

Hello, I have some issues with delays which I would appreciate very much if someone could please clarify for me, as they are not clear to me right now. I would like to know what the difference between an inertial delay and a transport delay is and why VHDL would need to have these two distinct types of delay. Also, it seems to me that specifying delays in VHDL designs can only serve the purose of simulation since the delays inherent in the physical hardware cannot, as far as I know, be controlled with software: they certainly cannot be made smaller than what they are, but I'm not sur...

The pipedream of Linux being used by Government is quickly fading. The first big deployment has been full of "snags" and "delays"... just like using Linux! We told everyone this, now the truth is known. - Munich announces delay in Linux migration into 2006 9/7/2005 4:55:02 PM, by Jeremy Reimer The municipal government of Munich, Germany released a statement yesterday that the migration of its office PCs to Linux and OpenOffice.org, which was scheduled to be completed in 2005, has slipped to at least next year. The original plan, which involved switching all 14,00...

http://www.kuee.kyoto-u.ac.jp/~kitano/paper/slp2/slp2.pdf They appear to get an output before there is an input! Surely some mistake... Hardy HardySpicer wrote: > http://www.kuee.kyoto-u.ac.jp/~kitano/paper/slp2/slp2.pdf > > They appear to get an output before there is an input! Surely some > mistake... Unfortunately they found it had already been reported in last month's journal. ;) I once wasted an entire day trying to do that (back when I was 21 or so). These guys don't seem to have got the memo about causality. Love to see them build one that works. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 845-480-2058 email: hobbs (atsign) electrooptical (period) net http://electrooptical.net On Jul 8, 9:30=A0pm, HardySpicer <gyansor...@gmail.com> wrote: > http://www.kuee.kyoto-u.ac.jp/~kitano/paper/slp2/slp2.pdf > > They appear to get an output before there is an input! Surely some > mistake... No mistake. They really do appear to advance the signal. They don't actually advance it, but they do appear to. Jerry -- Engineering is the art of making what you want from things you can get. > HardySpicer wrote: >> http://www.kuee.kyoto-u.ac.jp/~kitano/paper/slp2/slp2.pdf >> >> They appear to get an output before there is an input! Surely some >> mi...

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...

I've been racking my brain on this one the last couple of days. So, group delay is defined as the derivative of phase with respect to frequency. My simple question is: why? We would all agree that the time delay of a sinusoid induced by a change in phase (phase delay) is equal to the ratio of the change in phase to the frequency. Also, for a linear phase response, the derivative would be equal to the ratio. Both phase delay and group delay would be constant. I have been searching for a while now and haven't found anything beyond 'it can be shown that...' In Richard Lyons' book, he simply uses 'is defined as...' Could someone provide, or refer me to, a derivation showing the relationship between an amplitude modulated sinusoid and group delay? Cheers, -Dan "dszabo" <62466@dsprelated> writes: > I've been racking my brain on this one the last couple of days. So, group > delay is defined as the derivative of phase with respect to frequency. > > My simple question is: why? > > We would all agree that the time delay of a sinusoid induced by a change in > phase (phase delay) is equal to the ratio of the change in phase to the > frequency. > > Also, for a linear phase response, the derivative would be equal to the > ratio. Both phase delay and group delay would be constant. > > I have been searching for a while now and haven't found anything b...

Microsoft's Vista faces delays as public tests continue ,----[ Quote ] | David Bradshaw, principal analyst for Ovum, the technology research | group, said that delays to the full release of Vista remained a danger, | noting that such testing programmes are becoming increasingly normal. He | said that public testing programmes were useful in highlighting problems | of compatibility, where the software fails to work properly with certain | printers, software programs or hardware. | | Although the discovery of a problem could force a rewrite, Mr Bradshaw | said, "it would have to be a...

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 ...

When configuring a T1 and setting up the timeslots you have an option to set the channel group group number. What exactly does the "channel-group" group number do? Normally, I plug in 1, but you can set it from 0-23. channel-group ?? timeslots 1-24 speed 64 (?? is where the group number would go.) Thanks Amy. On 16 Dec 2004 10:53:42 -0800, amyl@paxemail.com wrote: ~ When configuring a T1 and setting up the timeslots you have an option ~ to set the channel group group number. What exactly does the ~ "channel-group" group number do? Normally, I plug in 1, but you can ~ set it from 0-23. ~ ~ channel-group ?? timeslots 1-24 speed 64 ~ (?? is where the group number would go.) ~ ~ Thanks ~ Amy. The channel-group number becomes part of the name of the serial interface you create. For example, if you do this: controller T1 2 channel-group 3 timeslots 1-24 speed 64 then this creates an interface called "Serial 2:3" You can configure multiple channel-groups (and/or ds0-groups if your platform supports it), so pick a unique channel-group/ ds0-group ID for each such group ... e.g. controller t1 2 channel-group 0 timeslots 1-4 speed 64 channel-group 1 timestots 5-12 speed 64 ds0-group 2 timeslots 13-24 type e&m-fgb Aaron ...

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...

Greetings. I'm looking to select data from a table and group by some values.. but I'm looking to limit the number of rows returned for each group, but not the entire query. Here's my table set up (Not from MySQL, just typed up.. but it'll give you the idea): CREATE TABLE bank_ident_all_t( ident_id INT(9) UNSIGNED ZEROFILL NOT NULL, ident_type ENUM('ach','cc') NOT NULL, bank_id INT UNSIGNED NOT NULL, ref_count INT UNSIGNED NOT NULL DEFAULT 1, last_updated INT UNSIGNED NOT NULL, PRIMARY KEY(ident_id, ident_type, bank_id), INDEX(ident_id, ident_type) )...

Indeed ... maybe 97000 is a magic number for them (96999 is the number of topics currently listed)? -Joe On Mon, Oct 27, 2008 at 6:41 PM, Richard <richard.hockey@gmail.com> wrote: > Anyone noticed that google groups is not updating SAS-L ? > Today the newest item is dated 2 days ago. > R > ...

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 cfy30 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? You just found it. What more do you want? (5-1)/2 bypasses d(theta)/d(omega). Jerry -- Engineering is the art of making what you want from things you can get. ����������������������������������������������������������������������� On 21 Mar, 20:02, "cfy30" <cf...@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? Well, there is the difference between *deriving* the group delay (that is, finding the formula), and *computing* the group delay. You can do the computation in two ways: - Observe that the filter's impulse response is symmetric, so the filter is linear phase and thus the group delay is constant (N-1)/2 = 2. I can't imagine any...

Hi , I have a trivial question .Could anyone explain the concept of linear phase and group delay . I went throught the books but I cant visualize the concept . Symmetric impulse response => Linear Phase and Constant group delay . but Linear Phase does not imply constant group delay . ?? Thanks in Advance Regards Vijay pcvijay30@gmail.com writes: > Hi , > > I have a trivial question .Could anyone explain the concept of linear > phase and group delay . I went throught the books but I cant visualize > the concept . > > Symmetric impulse response => Linear Pha...

Hi I have a JMeter script with 1 Thread Group that contains about 10 requests. I want the script to run indefinitely every 5 minutes with no delays between each individual requests and currently i cannot seem to find a way to do that. There are various Timers i can add to a Thread Group, all they do is delay individual requests as opposed to delaying the execution of the whole Thread Group. Does anyone know if there is a way to implement this? ...

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