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Continuous Sampling at high rates

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Continuous Sampling at high rates

Postby zzembower » Wed Jul 02, 2014 8:04 pm

Hello,

I am interested in using one of these oscilloscopes as a high speed data acquisition unit and function generator. I want to have the function generator output a triangle wave at a frequency of about 1kHz. I need to record the precise voltage (10 or more bit) being output from the generator and the voltage coming out of my circuit at a rate of about 10MS/s. I do not have anything to trigger on except the output of the function generator. I will be plotting the input signal as a function of voltage from the function generator. This should present me a peak from my circuit which should move as a function of time. I would like to take data for at least 1s without interruption. I think the 2206A should accomplish this task but I am not sure and am open to more suitable devices.

I know this will require a lot of post processing but I am confidant I can write something in C++ to find the peaks and brute force my way through 10 million data points per experiment.

Another possibility is to have the triangle wave go to 10kHz and only collect 1 out of every 10 sweeps at 100MS/s. I am not sure if this will be easier to do or not.

Thanks,
Zach
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Re: Continuous Sampling at high rates

Postby Hitesh » Mon Jul 07, 2014 9:15 am

Hi Zach,

If you require an oscilloscope with at least 10 bits and a function generator, then you may wish to consider the PicoScope 5000 Series Flexible Resolution Oscilloscopes.

http://www.picotech.com/picoscope5000-flexibleresolution.html

The onboard buffer memory is halved when 12-bit resolution is selected so for a 1 second capture at 10MS/s on a single channel, the PicoScope 5242B should be sufficient. For data captures over a short period of time, block mode capture would be fine.

The PicoScope 2206A does not have sufficient onboard memory for the above data capture, and streaming data capture rate is a maximum of 9.6MS/s.

It should be possible to collect 1 sweep out of 10 at 100MS/s but it would be a bit more complex if a number of waveforms are required - block or rapid block mode capture would be required here due to the sampling rate.

You can find descriptions of data capture modes in the Programmer's Guide for the PicoScope 5000 Series and elsewhere on our site:

http://www.picotech.com/education/oscilloscopes/data-acquisition-modes.html

Hope this helps.
Hitesh

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Re: Continuous Sampling at high rates

Postby zzembower » Mon Jul 07, 2014 5:27 pm

Thank you, Hitesh, for your fast response. I think my explanation of my requirements may have been unclear. I need the output from the function generator to at least 10-bits but the actual oscilloscope does not need to be that accurate. I noticed on the B models of your 3000 series scopes that the AWG has a resolution of 12-bits. Is there any way to pull that information out of the AWG directly without having to connect it to one of the inputs of the scope? If so, can it be done with one of the A models?

Thanks,
Zach
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Re: Continuous Sampling at high rates

Postby Hitesh » Tue Jul 08, 2014 11:15 am

Hi Zach,

Could you please clarify what is meant by:

Is there any way to pull that information out of the AWG directly without having to connect it to one of the inputs of the scope?


You can use PicoScope 6 or call the API directly to output a waveform from the signal generator to whatever the output is connected to.

The difference between the 'A' and 'B' variants in terms of the signal generator is that the 'B' variants have additional built in waveforms (Ramp, sinc, Gaussian, half–sine, white noise, PRBS) as well as an Arbitrary Waveform Generator allowing you to specify your own waveforms within certain limits.

Regards,
Hitesh

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Re: Continuous Sampling at high rates

Postby zzembower » Tue Jul 08, 2014 2:13 pm

Hi Hitesh,

I think the best way to describe what I mean is with an example.

Let's say I output a simple triangle wave with the built in function generator. If I am not mistaken, I already know some things without having to make any additional connections like the shape, frequency, and amplitude. However, I am still missing things like phase. Then I connect this output to drive a circuit that produces an output signal only when a specific voltage is attained and at no other time. If I connect the output of the circuit to input A of oscilloscope I should get a peak every time the triangle wave hits the specified voltage which should be twice a period. I wish to know the precise voltage that this peak appears at. To do this I think would need to connect the output of the function generator to input B of the oscilloscope so that I can measure both at the same time so that I can look for the peak and draw a vertical line to the triangle wave so that I know the voltage being output at that time. Depending on how this function generator works I could imagine acquiring this information without having to connect the output of the function generator to the input of the oscilloscope. Is this at all possible?

Thanks,
Zach
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Re: Continuous Sampling at high rates

Postby Hitesh » Tue Jul 08, 2014 2:50 pm

Hi Zach,

Thank you for the clarification.

It's not possible to retrieve the information from the oscilloscope - I guess you can make an assumption based on the signal being periodic. Using input B on the scope would be better to monitor the signal generator output.

You coud define your own waveform and use the AWG functionality provided by the 'B' variants. This may be a little complex.

Regards,
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