Creating Band-passed noise stimuli (Fatima Husain )

Subject: Creating Band-passed noise stimuli
From:    Fatima Husain  <fhusain(at)CNS.BU.EDU>
Date:    Thu, 5 Jun 1997 16:48:25 -0400

Hi All,
This is the first time I am addressing the List.

I am in the process of creating stimuli which are white noise bandpassed
through a filter. Basically I need a series of complex stimuli
centerd at different frequencies. I tried harmonic complexes but
found they can show beat and/or timbre effects which i could not control
for. I need the stimuli to change in a more or less orderly manner,
i.e. an individual shouldn't stand out from its neighbors (except
for the change of freq./pitch effects).
I have now settled for white noise bandpassed through say a butterworth
filter.

I am worried about two things : (a) choice of filter - is some other
filter a better choice? (b) is there a better way of generating such
stimuli rather than using bandpassed white noise?

Btw, I use a random number generator to generate white noise and then
low pass at 2 different freq.s. The difference is the bandpass stimulus.

Any input is appreciated.

Regards,
--fatima

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  Fatima Husain                         Dept. of Cognitive and Neural Systems
  fhusain(at)cns.bu.edu                    Boston University
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