PicoScope 7 Software
Available on Windows, Mac and Linux
Waveform capture rate
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Azibitsker
- Newbie
- Posts: 0
- Joined: Tue Jul 02, 2019 6:43 pm
Waveform capture rate
Hi guys,
Need your help.
I'm using PS 6404C with latest software downloaded from the website.
My question is, how do I set or know what is the current waveform capture rate?
I'm using ultrasonic pulser receiver to generate the signals at certain PRF, but the scope seems to capture the segments at arbitrary rate, never higher then 30 wvfms/s
Any ideas?
Need your help.
I'm using PS 6404C with latest software downloaded from the website.
My question is, how do I set or know what is the current waveform capture rate?
I'm using ultrasonic pulser receiver to generate the signals at certain PRF, but the scope seems to capture the segments at arbitrary rate, never higher then 30 wvfms/s
Any ideas?
Re: Waveform capture rate
Hi Azibitsker,
If you are (a) using a fast enough TimeBase (10ms or less), and (b) not completely filling the waveform buffer of the 6404C when you capture each waveform, then you can split the waveform buffer and use 'Rapid Trigger Mode' in PicoScope 6 (or Fast Block Mode in the SDK). This can give you waveform update rates well in excess of 1000 wvms/s, now depending more upon the Timebase itself (on a TimeBase of 1us you can exceed 500,000 wvms/s).
Ordinarily, when in Fast Sample Mode but using ordinary Triggers instead of Rapid Triggers in PicoScope 6, the PicoScope has to negotiate a transfer over the USB bus with the PC which typically takes 10's of milliseconds (depending upon how occupied the computer is, with other threads/resources being used, and on the availability of the bus) which is the reason for the waveform update rate that you were seeing. In Rapid Trigger Mode the Hardware PicoScope captures a number of waveforms (either the number you specify, or the number of waveforms that it would take to fill the waveform buffer, whichever is smaller) before negotiating to transfer them to the computer. So, the only delay between the waveforms is the time it takes to re-arm the Trigger (which for the PicoScope 6404C on fast Timebases is <1us).
Regards,
Gerry
If you are (a) using a fast enough TimeBase (10ms or less), and (b) not completely filling the waveform buffer of the 6404C when you capture each waveform, then you can split the waveform buffer and use 'Rapid Trigger Mode' in PicoScope 6 (or Fast Block Mode in the SDK). This can give you waveform update rates well in excess of 1000 wvms/s, now depending more upon the Timebase itself (on a TimeBase of 1us you can exceed 500,000 wvms/s).
Ordinarily, when in Fast Sample Mode but using ordinary Triggers instead of Rapid Triggers in PicoScope 6, the PicoScope has to negotiate a transfer over the USB bus with the PC which typically takes 10's of milliseconds (depending upon how occupied the computer is, with other threads/resources being used, and on the availability of the bus) which is the reason for the waveform update rate that you were seeing. In Rapid Trigger Mode the Hardware PicoScope captures a number of waveforms (either the number you specify, or the number of waveforms that it would take to fill the waveform buffer, whichever is smaller) before negotiating to transfer them to the computer. So, the only delay between the waveforms is the time it takes to re-arm the Trigger (which for the PicoScope 6404C on fast Timebases is <1us).
Regards,
Gerry
Gerry
Technical Specialist
Technical Specialist