variation in Data Set Length between saved files

Forum for discussing PicoScope version 6 (non-automotive version)
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Bob Mehew
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Joined: Tue Jun 16, 2009 10:07 am
Location: Southport

variation in Data Set Length between saved files

Post by Bob Mehew »

I have just found that if I set Picosoft to a single trigger and run for just one page to collect a notional 1 Mega set of samples, when I save the data in the .mat format I get 1,000,000 samples but when I save the data in the .csv format I get 1,000,004 samples. Whilst I see Picosoft disclaims a precision on the number of samples, I had expected to see the same number when saved in different formats from the same .psdata file. Is this a known bug? Fortunately I can step around it now I know about it.

Hitesh

Re: variation in Data Set Length between saved files

Post by Hitesh »

Hi Bob,

The effect you are seeing is likely to be expected behaviour, with the additional number of samples used to help with alignment on the screen (e.g. when triggers are in use).

Which version of the PicoScope 6 software are you using? If you are able to send a PicoScope 6 data file to support@picotech.com, we can run a check on the export.

Regards,

Bob Mehew
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Posts: 6
Joined: Tue Jun 16, 2009 10:07 am
Location: Southport

Re: variation in Data Set Length between saved files

Post by Bob Mehew »

I am using software version: 6.12.9.2917 . I note one also sees some padding of the file if one records less than a full wave form and then tries to save it as a full wave form using the Save as / all wave forms command. I will send a file to you but it occurs what ever the data source. (I found out about this when I was trying to sort out taking the data in a Python program and needed to check values between a .mat and .csv version of the data. It appears one gets a small and trivial difference due to I presume binary v decimal formatting of data.)

Hitesh

Re: variation in Data Set Length between saved files

Post by Hitesh »

Hi Bob,

I have responded via your support ticket and am posting back on here to provide clarification for other Users.

Extra samples are usually captured for alignment of the waveform in the window and also for processing (e.g. resolution enhancement and filtering).

With the .mat files, we have an ExtraSamples parameter which indicates the number of extra samples.

I have reported a bug in relation to this.

Regards,

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