BDF/EDF converter

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Gordak
Posts: 7
Joined: Sat May 03, 2014 12:11 pm

BDF/EDF converter

Post by Gordak » Sat May 03, 2014 12:22 pm

Hello

I record electrodermal activity with a Biosemi device. I currently read my data from as EDF file previously converted from the bdf file with the converter found on Biosemi website.
http://www.biosemi.com/download.htm

This converter applies a high pass filter on the data in addition to the conversion.
I would like to know what kind of filter is applied. I can access the "raw" data using a simple bdf reader, but I can't figure out which filter is used by the BDF to EDF file converter available on Biosemi website.
So the question is : do you know the type and parameters of the filter applied ? I think it does quite a good job !

Thanks a lot !

Coen
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Location: Amsterdam, Netherlands
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Re: BDF/EDF converter

Post by Coen » Tue May 06, 2014 12:00 pm

A first order high-pass is applied. Cut-off frequency (-3 dB point) and LSB for the (16-bit) EDF file are adjustable for making your own trade-off between bandwidth, resolution, and dynamic range (for GSR data, you probably want a much lower cut-off than the default 0.16 Hz, while an 1 uV LSB is accurate enough).

Best regards, Coen (BioSemi)

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