BDF duration of data record

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vojinilic
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Joined: Tue Dec 06, 2016 8:11 pm

BDF duration of data record

Post by vojinilic » Tue Dec 06, 2016 8:18 pm

Hi,

can you please tell what is minimum time of data record that can be set in BDF header? For example is sampling frequency is 500Hz, can I set duration of data record to be 0.002 (2ms)?

Regards,
Vojin

Coen
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Re: BDF duration of data record

Post by Coen » Fri Dec 09, 2016 4:19 pm

According to BDF specification, the minimum record duration is indeed the time of 1 sample per channel. However, ActiView always uses a record duration of 1 second. So, it is unlikely that BDF files exist with another record duration than 1 second.

Best regards, Coen (BioSemi)

vojinilic
Posts: 3
Joined: Tue Dec 06, 2016 8:11 pm

Re: BDF duration of data record

Post by vojinilic » Tue Dec 13, 2016 10:23 am

Thank you very much mr Coen,

I want to implement BDF data format on my MCU, so I cannon buffer 1s of data for each sample. Because of that I must log sample by sample. How much lower will be reading speed with storing sample by sample, or sample record in duration of 1s. Do you recommend to use this kind of data storing, or is it better to implement my own format and after writing to convert it to BDF file format.

Regards,
Vojin

Coen
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Posts: 969
Joined: Fri Mar 26, 2004 7:00 pm
Location: Amsterdam, Netherlands
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Re: BDF duration of data record

Post by Coen » Tue Dec 13, 2016 2:52 pm

If you have limited processor speed and buffer capacity, then I would recommend to use your own file format optimized for your particular hardware. You can then convert to BDF offline.

Best regards, Coen (BioSemi)

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