What does "freqz()" in matlab mean?

[leoren_tm]

what does "freqz()" in matlab mean????

Added after 8 minutes:

im doing a filter design...
pls help me..
in the figure..how can i determine the response using that funtion??

 

[standardon]

writing polynomials in matlab

what is new in matlab 2006a?

 

[Zahedpoor]

matlab help documents

Hi ,

I think make a mistake in writing command.

there isnt any command like fregz.

In matlab 7 sp3 if you write this Help freqz , no answer be seen.

regrds

 

[saberbf]

denominator and numertor

this function reflects to you the frequency response of a filter (or generally, a TF).
to solve the second part of question at 1st write the filter TF and then feed it to freqz() function.
for more info. in matlab command line write:
doc freqz

 

[louisnells]

freqz function in matlab

freqz is used to get or plot the frequency response of a digital system.
It can be used to get the frequency response of the filters.
To design the filters you have to first create the transfer function of the filter (ie: H(z)). Then pass the numerator and de-numerator to freqz().
Because you have the transfer function create polynomials of numertor and denominator and apply them to freqz().

It is also possible to create a transfer function of filter using "control system" functions and then use bode(). bode plot is much easier to handle.

 

[leoren_tm]

matlab help 2006

Hi ,

I think make a mistake in writing command.

there isnt any command like fregz.

In matlab 7 sp3 if you write this Help freqz , no answer be seen.

regrds

it,s freqz not fregz

Added after 2 minutes:

freqz is used to get or plot the frequency response of a digital system.
It can be used to get the frequency response of the filters.
To design the filters you have to first create the transfer function of the filter (ie: H(z)). Then pass the numerator and de-numerator to freqz().
Because you have the transfer function create polynomials of numertor and denominator and apply them to freqz().

It is also possible to create a transfer function of filter using "control system" functions and then use bode(). bode plot is much easier to handle.

thnks...
how can i transform that figure into a TF????
then using matlab to generate the filter...??
thx in advance

Added after 14 minutes:

this function reflects to you the frequency response of a filter (or generally, a TF).
to solve the second part of question at 1st write the filter TF and then feed it to freqz() function.
for more info. in matlab command line write:
doc freqz

when i type "doc freqz" it say

  Warning - Documentation Files Not Found
MATLAB is unable to find the HTML help documents, based on your current
Documentation location setting. Some possible reasons for this are as follows:

The Documentation location is set to your CD-ROM drive, but the Documentation
CD-ROM is not in the drive.
The setting is no longer valid, because the help files have been moved or
deleted.
The setting is incorrect, perhaps mistyped.

To view or change the location where MATLAB expects to find the help documents, click
here to bring up the Preferences window showing the Help Preferences. The
Documentation Location field shows the location of the help documents.

You can set your documentation location to any of the following alternatives (listed with
examples):


CD-ROM drive

Z:\help

Installed in the $MATLABROOT directory, or in
another location on your hard disk.

C:\MATLAB\HELP

Installed in a network location

\\CampusServer\Matlab\Help

 

[louisnells]

matlab freqz

The freqz() is even available with Matlab v6.1 (Linux). But bode() is more comfortable.

Reffer polynomials in matlab. You can create a polynomial from its co-efficients. So create the polynomials for numerator and denominator. Then pass it to freqz().

To create TF from the above reffer control system toolbox functions.

 

[leoren_tm]

matlab freqz low pass filter

can you give me a clue on that figure???

y=..????????

 

[louisnells]

matlab freqz with filter of image

The transfer function is attached

 

[leoren_tm]

matlab doc user-created html

thx for that...but can i have it in standard form???
in this one???

           jw               -jw              -jmw 
         jw  B(e)    b(1) + b(2)e + .... + b(m+1)e
      H(e) = ---- = ------------------------------------
                   jw               -jw              -jnw
               A(e)    a(1) + a(2)e + .... + a(n+1)e

thx sOOOOoo much.....
mwahhhhhhhhhhhhhhhhh............................

 

[louisnells]

doc tf matlab

For Matlab you need it in the Z-transform way.

thx for that...but can i have it in standard form???
in this one???

           jw               -jw              -jmw 
         jw  B(e)    b(1) + b(2)e + .... + b(m+1)e
      H(e) = ---- = ------------------------------------
                   jw               -jw              -jnw
               A(e)    a(1) + a(2)e + .... + a(n+1)e

thx sOOOOoo much.....
mwahhhhhhhhhhhhhhhhh............................

 

[leoren_tm]

simple low pass filter in matlab using tf command

aw..ok...
im implementing it in matlab.....
can you help me??
and what filter would that be??

 

[louisnells]

help freqz log

The TF looks like an IIR filter.

aw..ok...
im implementing it in matlab.....
can you help me??
and what filter would that be??

 

[leoren_tm]

location for matlab help files

hmm...thanks...
low pass or high pass??

 

[lxtommy]

matlab freqz 48

sorry, i have the presentation by using the matlab of the subject
- image processing
- wavelets
- DSP (digital signal processing)
so, if who has any the material of these subject, you can help me.
my mailL lxtommy@yahoo.com