Timebase vs downsampling

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bloer
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Timebase vs downsampling

Post by bloer » Thu Aug 16, 2018 8:35 pm

If I have a 5000a API scope, and I have 1 channel enabled and resolution set to 8 bits, I can get an effective 8 ns per sample in two ways:

1) set the timebase to 3
2) Set the timebase to 0 and set downsampleRatio to 8

Aside from more efficient use of the scope's memory buffer, is setting a higher timebase (slower sampling rate) the same as downsampling with RATIO_MODE_DECIMATE? Or does the scope do some sort of sample averaging/filtering internally at higher timebase values?

Martyn
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Re: Timebase vs downsampling

Post by Martyn » Fri Aug 17, 2018 12:49 pm

Both methods will result in the same data.
Martyn
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bloer
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Re: Timebase vs downsampling

Post by bloer » Fri Aug 17, 2018 3:39 pm

Thank you Martyn. Another point of clarification: When I call GetValues. should the 'noOfSamples' parameter be the number before or after downsampling? E.g. if I have 1000 total samples and a downsample factor of 4, should noOfSamples be 1000 or 250?

Martyn
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Re: Timebase vs downsampling

Post by Martyn » Tue Aug 21, 2018 9:09 am

It should be 250
Martyn
Technical Support Manager

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