Reply by Jeff Brower February 21, 20052005-02-21
Sridhar-

>
> I tested digital filter by giving the sweep signal. Is there any other
> method to basically check, filter is working or not ??

One way is to run an impulse through your filter:

for n=0 to N-1

if (n == 0) x[n] = 1
else x[n] = 0

y[n] = a0*x[n] + a1*x[n-1] + a2*x[n-2] ... + b0*y[n-1] + b1*y[n-2] + ...

end

then take FFT(y).

The above example is for IIR filter; if you are using FIR filter, then all bn = 0.
To get the impulse response length, you can make N something like 4096 or you can
watch y[n] output until it becomes flat and no longer changes.

-Jeff



Reply by Jeff Brower February 21, 20052005-02-21
Sridhar-

>
> I tested digital filter by giving the sweep signal. Is there any other
> method to basically check, filter is working or not ??

One way is to run an impulse through your filter:

for n=0 to N-1

if (n == 0) x[n] = 1
else x[n] = 0

y[n] = a0*x[n] + a1*x[n-1] + a2*x[n-2] ... + b0*y[n-1] + b1*y[n-2] + ...

end

then take FFT(y).

The above example is for IIR filter; if you are using FIR filter, then all bn = 0.
To get the impulse response length, you can make N something like 4096 or you can
watch y[n] output until it becomes flat and no longer changes.

-Jeff



Reply by Dr.Rajanish Kamat February 20, 20052005-02-20

The most important tests for the digital filters is the stability. The simplest thing would be to use graphical root-locus technique or most sophisticated FFT based oepstral method. This will certainly validate your design of digital filter..


Sridhar gadda <s...@yahoo.com> wrote:
Hello,
 
            I tested digital filter by giving the sweep signal.  Is there any other method to basically check, filter is working or not ??
 
  



http://www.dsprelated.com/groups/matlab/1.php

_____________________________________
Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer.  You need to do a "reply all" if you want your answer to be distributed to the entire group.

_____________________________________
About this discussion group:

Archives:  http://www.dsprelated.com/groups/matlab/1.php

To Post:  Send an email to m...@yahoogroups.com

Other DSP Related Groups: http://www.dsprelated.com/groups.php



Dr. Rajanish Kamat email: r...@ieee.org
Electronics Department, Ph: +91-9422437331
Goa University,
GOA - 403 206
INDIA



Reply by Lark...@ AS February 18, 20052005-02-18

Sridhar,

Response to a step input is a quick way to check the time tomain response.

Regards,
Jon

_____

From: Sridhar gadda [mailto:]
Sent: Thursday, February 17, 2005 11:23 AM
To:
Subject: [matlab] How to test filter is working or not Hello,

I tested digital filter by giving the sweep signal. Is there
any other method to basically check, filter is working or not ??


Reply by Sridhar gadda February 17, 20052005-02-17
Hello,
 
            I tested digital filter by giving the sweep signal.  Is there any other method to basically check, filter is working or not ??