How to set the frequency span THD measurements

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Nicolai
Newbie
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Joined: Thu Mar 23, 2017 1:53 pm

How to set the frequency span THD measurements

Post by Nicolai » Thu Mar 23, 2017 1:59 pm

How do I set the frequency span for a THD measurement to a defined frequency range such as 20 Hz to 20 kHz?
I know the drop-down menu to choose which section of the graph to measure, but the only option is "whole trace".
Thanks,
Nicolai

Gerry
PICO STAFF
PICO STAFF
Posts: 292
Joined: Mon Aug 11, 2014 11:14 am

Re: How to set the frequency span THD measurements

Post by Gerry » Thu Mar 30, 2017 9:18 am

Hi Nicolai,

To set the upper range is obviously just a case of setting the Spectrum span to 20kHz.

In Spectrum mode any DC component is avoided by ignoring the first 5 bins. So, if you then opt for a bin width of around 4Hz the lower range will be in the region of 20Hz. You can get a bin width of approx 4Hz by setting the number of bins to 4096 (closest you can get to 20Khz/4), and you can verify the bin width by turning on the Properties pane when you select 'View Properties', under the 'View' menu.

Regards,

Gerry
Gerry
Technical Specialist

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