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Problem copying data from PicoScope memory

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Problem copying data from PicoScope memory

Postby davidweisgerber » Tue Oct 27, 2009 10:43 am

Hi,
another question which gives us headaches. First what we want to do: We have one source which gives us an analog signal that needs to be analyzed with 2µs sample rate. The signal needs to be processed as fast as possible.
At the moment we run in fast streaming mode with a huge buffer. If we call ps2000_get_streaming_last_values at a frequency of 20 Hz or 15 Hz, the buffer sizes which are given to the callback function are very fluctuating. If I run with the same code at 10 Hz, the buffer sizes are as expected.
The problem is that we need a frequency of at least 20 Hz... How would you implement that? We are playing with a lot of values and the behavior of the PicoScope is not always predictable...
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Re: Problem copying data from PicoScope memory

Postby Robin » Wed Oct 28, 2009 9:54 am

Hi David

As described in the previous post (post15683.html#p15683), the driver has a circular buffer. When you call ps2000_get_streaming_last_values it returns samples up to the end of the buffer. Any samples new samples that have been written to the start of the buffer will not be returned until the next call. This is bound to lead to variation in the number of samples returned.

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