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Total power in spectrum mode

Forum for discussing PicoScope version 6 (non-automotive version)

Total power in spectrum mode

Postby Tech Hiker » Fri Apr 08, 2016 1:10 am

One of the measurements that can be made with PicoScope 6 in Spectrum Mode is Total Power and I'm trying to understand what that is.

Here is my setup, and spectrum mode settings.
PiccoScope 2205A.
Input signal is 1khz, 7 volts RMS pure sine from a signal generator.
Input range 20V, DC coupling
Spectrum range 24.41khz.
Spectrum bins 16384
Window function Blackman
Display mode Magnitude
Scale Log
Log unit dBu
x scale log10
Num decades 3

When I add a measurement for Total Power(Whole trace) it gives me 6.5 watts. Where did this 6.5 number come from? That number is way too big for a 600 ohm reference load.

Tom
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Re: Total power in spectrum mode

Postby TomVeik » Thu Apr 14, 2016 3:46 pm

Does anyone know the answer to this question?

Tom
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Re: Total power in spectrum mode

Postby Gerry » Fri Apr 15, 2016 8:28 am

Hi Tom,

Unfortunately this is an error in our software. The calculation is done correctly in PicoScope 6.12 and later versions of software, and calculated as:

power = (sum of (V^2)) / impedance

You can download our latest Beta (version 6.12.1 from here: https://www.picotech.com/downloads/_lig ... Scope6Beta) to perform the calculation correctly.

Regards,

Gerry
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Re: Total power in spectrum mode

Postby TomVeik » Fri Apr 15, 2016 12:37 pm

Okay, thanks.

Tom
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Re: Total power in spectrum mode

Postby TomVeik » Thu May 12, 2016 1:37 pm

I installed the beta today and I'm getting the error
No suitable device found.

How do I fix this?

Tom
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Re: Total power in spectrum mode

Postby Gerry » Fri May 13, 2016 3:43 pm

Hi Tom,

First of all, our help desk is probably a better medium for this kind of problem, so it may be better to send an email in to us at support@picotech.com marked for my attention.

How did you install the Beta version? Could you walk us through the steps that you took (including what you did with the non-beta version of PicoScope 6, and at what point you connected the Hardware PicoScope).

There are a number of potential causes for the communication problem, so we need to eliminate some of the more common issues. There is a self-help guide for connection problems like this which you can find here: https://www.picotech.com/download/manua ... uide-1.pdf.
This will take you through a series of checks to perform (in particular establishing if a valid PicoScope device driver exists for your model of PicoScope, and sending in a 'trace.xml' file to us if none of the checks or suggestions help).

Regards,

Gerry
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