resampling signals in matlab 2012b

hello i want to downsampling a signal with 173HZ and 23.6s to 120HZ ,can i do it with matlab 2012b ?

Answer 1

[m]

yes, i have signalprocessing toolbox,but i cant use '_resample()_' can you tell me about parameters (173 hz to 120 hz)? thanks.

[Jan]

Matlab help says:

y = resample(x,p,q) resamples the sequence in vector x at p/q times the original sampling rate, using a polyphase filter implementation. p and q must be positive integers. The length of y is equal to ceil(length(x)*p/q). If x is a matrix, resample works down the columns of x.

i.e. in your case p=120 and q=173, so:

 x_resampled = resample( x, 120, 172 )

should do the trick.

[m]

thanks for your answer,i run it but get this error: "_Too many input arguments._" do you know this error? my x variable is eq 4096

[Jan]

Check the type of your signal. It should be either a vector or a 2-d matrix.

[m]

can i attach the file of sampled signal to this comment, that you can see it?

[Jan]

Before you start uploading files: how do you load the signal into the Matlab environment and what kind of signal is it that you are dealing with?

[m]

i want to import the eeg signal ,the file has 4097 numbers,i use import from menu then import it to a variable,and the file has one column... i think matlab has a bug with this function because when i try to run sample code of 'resample' i see this error again !

[Jan]

In the Matlab command line type whos and post the output.

Also type the variable name and post that output, too.

[m]

my input command : y=resample(inputsig,120,173); output : Error using resample Too many input arguments.

my enviroment report : Name Size Bytes Class Attributes

inputsig      4097x1               32776  double              
y                1x4098            32784  double

[Jan]

Could you type

 which resample

and post that output?

[Walter Roberson]

Please post the result of

which -all resample

[m]

ofcourse, the output is :E:\edu\ARSHAD AI\classes\EVALUATIONARY ALGORITHMS\Project\Steps\Data\resample.m

do you think the path is so long?

[Jan]

No, there is a function in your project that is called resample too which hides Matlab's resample function. Unload the path you just posted from your environment and try to call resample again.

[m]

E:\edu\ARSHAD AI\classes\EVALUATIONARY ALGORITHMS\Project\Steps\Data\resample.m C:\Program Files\MATLAB\R2012b\toolbox\matlab\timeseries\@timeseries\resample.m C:\Program Files\MATLAB\R2012b\toolbox\ident\ident\@iddata\resample.m C:\Program Files\MATLAB\R2012b\toolbox\simbio\simbio\@SimData\resample.m C:\Program Files\MATLAB\R2012b\toolbox\matlab\timeseries\@tscollection\resample.m C:\Program Files\MATLAB\R2012b\toolbox\signal\signal\resample.m

[m]

after i delete my resample function : C:\Program Files\MATLAB\R2012b\toolbox\signal\signal\resample.m

[m]

OK OK ,after delete my resample function it works well... thanks so much

[Jan]

No problem... but next time check which answer you chose as 'accepted answer' (:

[m]

yes,sorry..

Answer 2

[Jan]

If you have the Signalprocessing Toolbox use resample() or decimate()

If not, look at interp1()