What is the storage capacity in practice?

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The Boojum
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What is the storage capacity in practice?

Post by The Boojum »

Hi,

I'm looking at one of the Picoscope 2200 series as a hobby 'scope but am confused by the references to the amount of data that the scopes can store.

If I've understood correctly, there are two approaches: to stream the 'raw' data in real time directly to the PC for storage. The data can be acquired at a rate between "1 and 9.6MS/s". The second is to use the on-board storage. Depending on model this ranges from "8kS to 48kS". There is also the waveform buffer which can store up to "10,000 waveforms." So far, so good.

The starting point for what I don't understand is what is the the "S" in kS/s and MS/s? Is it a single data point, i.e. one data point reading at one instant in time? In which case, even 48kS isn't going to last the blink of an eye. And how big (i.e. over how long a period) is one 'waveform'?

To put it in practical terms, say I wanted to capture say 5 seconds of a trace from an output of an Arduino board, how much storage is that going to take up in the above terms? Is it within the capacities?

Basically I'd be grateful for a primer on the scope storage.

Many thanks,

The Boojum

Martyn
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Re: What is the storage capacity in practice?

Post by Martyn »

Firstly S is samples, or individual data points as other companies may reference it.

If you were looking at a continuous 5 seconds of data, and you need to see all of it gap free, then this would need to be handled using streaming mode, setting a timebase of 500ms/div, and limited to a maximum sample rate of 9.6MS/s

However if you weren't interested in all of the 5 seconds of data, but data around a specific event, then this could be handled by block mode and triggers. This would be by arming a trigger, capturing a block of data, transferring this to the PC, re arming the trigger, capturing the next block etc. There would be gaps in the overall data stream, but these would generally be for data you are not interested in, and instead the actual data around the trigger could be shown in greater detail, greater than 50MS/s.

It really depends upon the exact data you are looking at be able to define the best approach
Martyn
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