f



Group delay in Matlab

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 17 samples. 

But it not what I obtain! I have made a lot of tests with different inpu
frequency in the range [0...fs/2] and I always get a smaller delay tha
what I should expect from the group delay response of the filter.

Does anyone have an explaination to provide me?
It sounds to me really basic and I am really wasting my time with it!!!

Thanks for your help 
Gabriel






0
9/18/2006 4:27:52 PM
comp.dsp 20333 articles. 1 followers. allnor (8509) is leader. Post Follow

6 Replies
457 Views

Similar Articles

[PageSpeed] 22

gab said the following on 18/09/2006 17:27:
> Dear all
> 
> I not very familiar with filter design in Matlab and I am probably missing
> 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 delay
> response (plotted with grpdelay[b,a] in matlab with a,b the filter
> coefficients) provides 17 as the group delay (in samples) at f=0.14
> (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequency
> being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through the
> filter I should get at the output the same sinusoid (assuming gain is one)
> delayed by 17 samples. 
> 
> But it not what I obtain! I have made a lot of tests with different input
> frequency in the range [0...fs/2] and I always get a smaller delay than
> what I should expect from the group delay response of the filter.
> 
> Does anyone have an explaination to provide me?
> It sounds to me really basic and I am really wasting my time with it!!!

I think you are confusing group delay and phase delay.  Phase delay is 
defined as:

     t = phi/omega

whereas group delay is:

     t = d phi / d omega

[i.e. the derivative].

Phase delay is the absolute delay at a given frequency, and I think this 
is what you were expecting from your simulation.


-- 
Oli
0
catch (918)
9/18/2006 4:57:28 PM
gab wrote:

> Dear all
> 
> I not very familiar with filter design in Matlab and I am probably missing
> 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 delay
> response (plotted with grpdelay[b,a] in matlab with a,b the filter
> coefficients) provides 17 as the group delay (in samples) at f=0.14
> (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequency
> being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through the
> filter I should get at the output the same sinusoid (assuming gain is one)
> delayed by 17 samples.
> 
> But it not what I obtain! I have made a lot of tests with different input
> frequency in the range [0...fs/2] and I always get a smaller delay than
> what I should expect from the group delay response of the filter.
> 

Of course you have taken into account that 17 samples is ~2.7 samples over
the wavelength? Thus, it might seem that the delay is smaller (i.e., 2.7).

> Does anyone have an explaination to provide me?
> It sounds to me really basic and I am really wasting my time with it!!!

If you truly are interested in how much a sine wave is delayed then you
should use the phase delay as Oli has advised you. However, if you're
interested in the delay of bandlimited signal around f=0.14, then group
delay is the weapon of choice (assuming that the phase is sufficiently
linear around f=0.14)

Check this link for an introduction to subject:
http://ccrma.stanford.edu/~jos/filters/Phase_Response_Applications.html

> 
> Thanks for your help
> Gabriel

-- 
Jani Huhtanen
0
9/18/2006 6:00:35 PM
What's your application here?  What type of filter is this?

* Group name: RealTime_Signal_and_Control
* Group home page:
http://groups.google.com/group/realtime_signal_and_control
* Group email address realtime_signal_and_control@googlegroups.com

Jani Huhtanen wrote:
> gab wrote:
>
> > Dear all
> >
> > I not very familiar with filter design in Matlab and I am probably missing
> > 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 delay
> > response (plotted with grpdelay[b,a] in matlab with a,b the filter
> > coefficients) provides 17 as the group delay (in samples) at f=0.14
> > (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequency
> > being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through the
> > filter I should get at the output the same sinusoid (assuming gain is one)
> > delayed by 17 samples.
> >
> > But it not what I obtain! I have made a lot of tests with different input
> > frequency in the range [0...fs/2] and I always get a smaller delay than
> > what I should expect from the group delay response of the filter.
> >
>
> Of course you have taken into account that 17 samples is ~2.7 samples over
> the wavelength? Thus, it might seem that the delay is smaller (i.e., 2.7).
>
> > Does anyone have an explaination to provide me?
> > It sounds to me really basic and I am really wasting my time with it!!!
>
> If you truly are interested in how much a sine wave is delayed then you
> should use the phase delay as Oli has advised you. However, if you're
> interested in the delay of bandlimited signal around f=0.14, then group
> delay is the weapon of choice (assuming that the phase is sufficiently
> linear around f=0.14)
>
> Check this link for an introduction to subject:
> http://ccrma.stanford.edu/~jos/filters/Phase_Response_Applications.html
> 
> > 
> > Thanks for your help
> > Gabriel
> 
> -- 
> Jani Huhtanen

0
frank.agee (26)
9/19/2006 8:30:45 AM
What's your application here?  What type of filter is this?

* Group name: RealTime_Signal_and_Control
* Group home page:
http://groups.google.com/group/realtime_signal_and_control
* Group email address realtime_signal_and_control@googlegroups.com

Jani Huhtanen wrote:
> gab wrote:
>
> > Dear all
> >
> > I not very familiar with filter design in Matlab and I am probably missing
> > 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 delay
> > response (plotted with grpdelay[b,a] in matlab with a,b the filter
> > coefficients) provides 17 as the group delay (in samples) at f=0.14
> > (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequency
> > being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through the
> > filter I should get at the output the same sinusoid (assuming gain is one)
> > delayed by 17 samples.
> >
> > But it not what I obtain! I have made a lot of tests with different input
> > frequency in the range [0...fs/2] and I always get a smaller delay than
> > what I should expect from the group delay response of the filter.
> >
>
> Of course you have taken into account that 17 samples is ~2.7 samples over
> the wavelength? Thus, it might seem that the delay is smaller (i.e., 2.7).
>
> > Does anyone have an explaination to provide me?
> > It sounds to me really basic and I am really wasting my time with it!!!
>
> If you truly are interested in how much a sine wave is delayed then you
> should use the phase delay as Oli has advised you. However, if you're
> interested in the delay of bandlimited signal around f=0.14, then group
> delay is the weapon of choice (assuming that the phase is sufficiently
> linear around f=0.14)
>
> Check this link for an introduction to subject:
> http://ccrma.stanford.edu/~jos/filters/Phase_Response_Applications.html
> 
> > 
> > Thanks for your help
> > Gabriel
> 
> -- 
> Jani Huhtanen

0
frank.agee (26)
9/19/2006 8:30:52 AM
gab wrote:
> Dear all
>
> I not very familiar with filter design in Matlab and I am probably missing
> 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 delay
> response (plotted with grpdelay[b,a] in matlab with a,b the filter
> coefficients) provides 17 as the group delay (in samples) at f=0.14
> (normalized frequency so f=0.14*fs/2=0.14*500=70Hz, sampling frequency
> being 1000 Hz) then passing a sinusoid whose frequency is 70Hz through the
> filter I should get at the output the same sinusoid (assuming gain is one)
> delayed by 17 samples.
>
> But it not what I obtain! I have made a lot of tests with different input
> frequency in the range [0...fs/2] and I always get a smaller delay than
> what I should expect from the group delay response of the filter.
>
> Does anyone have an explaination to provide me?
> It sounds to me really basic and I am really wasting my time with it!!!

As others have already stated, there may be issues with the sinusoidal
period vs the delay, or confusion with phase velocity.

Yet another potential issue is whether the group velocity makes sense
for monochromatic signals. Group velocity is defined as

vg = dw/dk

where k is wavenumber and w is the angular frequency.

Since there are differentials involved, the signal necessarily
needs to be broad-band, which a single sinusoidal is not.

Maybe the group velocity is easier to come to terms with if
you apply a broad-band pulse to the system.

As for wasting your time: These issues are deceptively
simple. I spent 3 years pondering such questions before
finding some explanations I could accept. Look for a paper
by Johan Leander in the Journal of the Acoustical Society
of America, late -95 or -96, to become even more confused... 

Rune

0
allnor (8509)
9/19/2006 9:33:55 AM
Thank you for your guidance,

Of course it is the concept of "phase delay" which applies to a singl
sinusoide.

That solves one problem.

But if now we consider a baseband signal (I am actually working with a
OFDM signal DVB-T standard 2k mode, at the baseband stage after makin
IFFT of the symbols, and convolution with the pulse shape function). 
want to filter out all the frequencies which come from sampling at highe
speed (pulse shape sampled at fs=365 MHz) in the frequency domain and kee
only the signal of interest at baseband (0 to fmax=3.8 MHz).

I use a butterworth filter with cutoff frequency 18MHz and order 13.

From what I have read (c
http://ccrma.stanford.edu/~jos/filters/Derivation_Group_Delay_Modulation.html
I should check first that the phase response is linear between 0 and 3.
MHz and if yes the delay of the signal after the filter should be equal t
the group delay taken at 0 frequency that is to say in the case o
butter[13,1/20] 57 samples!

Am I correct or am I missing again something?

If this is true I am still misunderstanding something since by refering t
the pape
http://www.ece.gatech.edu/research/labs/sarl/tutorials/OFDM/Tutorial_web.pdf#search=%22ofdm%20simulation%20using%20matlab%2
 it is said (page 9) that the delay produced by filtering is 64!!! I canno
get this!

Thanks to let me know if you have further clear view on that point.

Gab



0
9/19/2006 11:45:15 AM
Reply:

Similar Artilces:

DSP Group TeakLite DSP Board
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. ...

Bar Plot in MATLAB
Hi all, I have a MATLAB Bar Plot question for the group. I'm generating a bar plot using the following command in MATLAB: bar(data); where 'data' is a 3x4 matrix that looks like this: data = [ 3, 7, 5, 2; 4, 3, 2, 9; 6, 6, 1, 4;] Using the bar plot command, this correctly gives me three groups of four bars each. The problem comes in when coloring the bars. The built-in colormaps, and all custom color maps I've created and tried myself, all result in an undesirable coloring behavior. I would like ALL four bars in the first group to be color A, ALL four bars in the second group to be color B, and ALL four bars in the third group be color C. (This is natural since the groups are actually correlated with colors). Unfortunately, what is happening instead is, the FIRST bar in EACH of the three groups is color A, and SECOND bar in each group is color B, the third bar in each group is color C, and finally the fourth bar in each group is color D. Does anyone know of a way where I can get the first coloring behavior (all four bars in each group the same color), instead of the second behavior (the Nth bar in each group is the same color)? Any help is very much appreciated. Respectfully, --Mike > > data = [ > 3, 7, 5, 2; > 4, 3, 2, 9; > 6, 6, 1, 4;] I would like ALL four bars in the > first group to be color A, ALL four bars in the second group to be > color B, and ALL four bars in the third group be color C. data = [3, 7, 5, 2;4,...

CIC Group Delay
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...

negative group delay
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 >...

Google groups delay
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 ...

group delay time?
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 >...

Delay Finder Matlab
Hi everyone, I'm working in a Real–Time Implementation of an Adaptive LMS Filter. Actually I'm using the DSP System Toolbox to play and record the signals and then generate a MEX file to increase performance for Real–Time. I need to record a signal played through a speaker (Pink Noise or maybe Music) and that signal must be processed by the LMS to get some desired coefficients and then filter that signal. That process starts again until the error vector is zero. The problem that I have is that the error generated by the LMS can't never be reduced because MAYBE the delay between t...

group delay equalizer
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...

finding delay in the matlab
I give a ramp (it can be any signal) to a butterworth filter and i want to find the delay between input signal and output signal. I tried xcorr function but it does not work....what is the fastest way to find delay. x = [1:101]; [n,d]=butter(5,0.1); y=filter(n,d,x); In the above example I want to find delay between x and y. Thanks Kirk Hazel wrote: > > > I give a ramp (it can be any signal) to a butterworth filter and i > want to find the delay between input signal and output signal. I > tried xcorr function but it does not work....what is the fastest > way > to find del...

how to generate delay in MATLAB
I wanna generate a filter"H(z)" with simple delay function w(n)-->H(Z)-->y(n) H(Z)=Z^(-1) y(n)=filter("????",1,w(n)) Sorry for the stupid question! Thanks R. you want y[n]=w[n-1]; so b=[0 1]; a=[1]; now y=filter(b,a,w) I hope it works A. Kumar Richard wrote: > > > I wanna generate a filter"H(z)" with simple delay function > > w(n)-->H(Z)-->y(n) > > H(Z)=Z^(-1) > > y(n)=filter("????",1,w(n)) > > Sorry for the stupid question! > > Thanks > > R. ...

Negative Group Delay ... again!
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...

phase to group delay
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...

Filter Group Delay
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. ...

delays: inertial delays vs. transport delays
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...

Linux Fails in Munich, Delays, Delays, Delays
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...

Finding the group delay of a filter
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...

Group By, Limit only group?
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) )...

Matlab Legend for group of entries....
Hi, I am trying to get one legend for a stack of lines...I found the following example code at mathworks , but doesnt work... can anynone help me out ?? shiva. t = 0:.1:2*pi; for k=1:5 offset = k/7; m(:,k) = t+offset'; end hSLines = plot(t,sin(m),'Color','b');hold on hCLines = plot(t,cos(m),'Color','g'); hSGroup = hggroup; hCGroup = hggroup; set(hSLines,'Parent',hSGroup) set(hCLines,'Parent',hCGroup) % Include these hggroups in the legend: set(get(get(hSGroup,'Annotation'),'LegendInformation'),... 'IconDispla...

group delay DC filter
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...

Channel-Group Groups
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 ...

Is this group only a Google group?
Hello, I'm discovering APL and I posted a question yesterday on the comp.lang.apl = nntp group. While searching for more information about APL, I stumbled upon= this Google group. I see that it has the same posts than the nntp group, b= ut the last nntp post is from October 1st, 2014. I'm thus wondering if there is are synchronization issues between nntp and = the Google group, or if the problem is with my nntp provider. Thanks, Alan Hi, comp.lang.apl is definitely a usenet group. Many providers aren't retaining many newsgroups long enough and also seem to ...

[News] Windows Vista: Delays, Delays, More Delays and Doubt
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...

Question about DSP in Matlab (beginner)
Hi, I'm starting to learn DSP (Matlab )and I have two questions about it, maybe someone can help me out? I'm trying to measure a frequency from an Audio Device and I'm using FFT to transform it from the time domain to the frequency domain. But I am doing a downsample before the FFT. But you can also do it after the FFT. Do you know what would be the most efficient (before or after)? And why? Another question, I am using zero padding to increase my system resolution (up to 50Hz). My frame length is N=256 and sample frequency fs= 44100 Hz. So 44100/50 = 882, so I need to add 626 zeroes (to 256 frame length) to get 50 Hz resolution, I hope this is correct? I believe this is done for FFT. But is this the same for the DFT? Thank you and regards, --------------------------------------- Posted through http://www.DSPRelated.com >Hi, > >I'm starting to learn DSP (Matlab )and I have two questions about it, >maybe someone can help me out? > >I'm trying to measure a frequency from an Audio Device and I'm using FFT >to transform it from the time domain to the frequency domain. But I am >doing a downsample before the FFT. But you can also do it after the FFT. >Do you know what would be the most efficient (before or after)? And >why? > >Another question, I am using zero padding to increase my system >resolution >(up to 50Hz). My frame length is N%6 and sample frequency fs= 44100 >...

Filter Design, group delay
Hello, I am looking for a way to obtain the lowest group delay. The specifications are; Lowpass filter fpass=1kHz with 3dB Ripple fstop=4kHz Attenuation 60dB (between 4kHz and 20kHz or between 4kHz and 97.5kHz) with sampling frequency: 195kHz up to 1kHz linear phase and constant group delay (needed) If I use Generalized Equiripple FIR filter of Matlab fda toolbox, th minimum order is 115 (so 57.5 Tabs delay) Is it possible to obtain a new filter which has a delay less than 57. Tabs for the given specifications? Best Regards Gokhan On 12 Okt, 04:58, "gapaydin" <apadi...@yahoo.com> wrote: > Hello, > > I am looking for a way to obtain the lowest group delay. > The specifications are; > > Lowpass filter > fpass=1kHz with 3dB Ripple > fstop=4kHz > Attenuation 60dB (between 4kHz and 20kHz or between 4kHz and 97.5kHz) > with sampling frequency: 195kHz > up to 1kHz linear phase and constant group delay (needed) > > If I use Generalized Equiripple FIR filter of Matlab fda toolbox, the > minimum order is 115 (so 57.5 Tabs delay) > > Is it possible to obtain a new filter which has a delay less than 57.5 > Tabs for the given specifications? I would be very surprised if you can reduce the group delay significantly. Since you require constant group delay you are commited to symmetric FIR filters. Which means that the task is to design the shortest symmetric FIR filter which attains the spec. You may be able to s...

Web resources about - Group delay in Matlab - comp.dsp

Undocumented Matlab
Undocumented, unsupported and hidden features in Matlab

Matlab Upazila - Wikipedia, the free encyclopedia
... 23°21′N 90°42.5′E  /  23.35°N 90.7083°E  / 23.35; 90.7083 Coordinates : 23°21′N 90°42.5′E  /  23.35°N 90.7083°E  / 23.35; 90.7083 Matlab ...

Open Directory - Science: Math: Software: MATLAB
The MathWorks - Developers of MATLAB, Simulink and Stateflow. Offers products for data analysis, visualization, application development, simulation, ...

MATLAB Mobile on the App Store
Read reviews, compare customer ratings, see screenshots, and learn more about MATLAB Mobile. Download MATLAB Mobile and enjoy it on your iPhone, ...

The Smart Emergency Response System Using MATLAB and Simulink - YouTube
In the aftermath of an earthquake, every second counts for disaster victims. Imagine a system that can locate people quickly and help first responders ...

The A-Z of Programming Languages: MATLAB
What prompted the development of MATLAB?

Matlab: Invalid .NET Framework. Either the specified framework was not found or is not currently supported ...
If you are trying to compile Matlab into .Net framework, you might encounter this message, even though you have the .Net framework installed ...

Matlab edges closer to electronic design automation world
Matlab, one of the world's most widely used products for algorithmic development, has long occupied its own niche far removed from EDA and hardware ...

Can I/How do I use DMTCP with a parallel pool of MATLAB workers? · Issue #223 · dmtcp/dmtcp · GitHub
dmtcp - DMTCP: Distributed MultiThreaded CheckPointing matlab -nodisplay -r "parpool('local',4); parfor i=1:10, pause(1); fprintf('%i ',i); end; ...

Using MATLAB and SDR to Reverse Engineer 433MHz Messages
... so he focused on studying the methodology and the tools available for analyzing 433MHz RF transmission. He describes the process of using MATLAB ...

Resources last updated: 3/30/2016 1:16:38 AM