1.05h triggering oddities
BradC
Posts: 2,601
I've plugged a signal generator into my Propscope. I have a 15.9Khz sine wave at 1.27v p-t-p.
I've selected CH1 trigger, Level : Normal, Edge : Rise, Mode : Continuous, and a trigger level of 108mv.
It's "reasonably" reliable until I select a timebase of 2uS or less, at which point all the wheels spectacularly fall off and the display "glitches" continuously with what looks like broken samples around the trigger point.
Same deal with a standard NTSC video signal trying to get it to trigger on the falling edge of the sync pulse. It's ok > 2uS, but at 2uS or lower it just falls apart.
I'm running this on XP, on the bare metal (not in a VM) on a very recent dual core laptop with 4G of ram.
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"Are you suggesting coconuts migrate?"
I've selected CH1 trigger, Level : Normal, Edge : Rise, Mode : Continuous, and a trigger level of 108mv.
It's "reasonably" reliable until I select a timebase of 2uS or less, at which point all the wheels spectacularly fall off and the display "glitches" continuously with what looks like broken samples around the trigger point.
Same deal with a standard NTSC video signal trying to get it to trigger on the falling edge of the sync pulse. It's ok > 2uS, but at 2uS or lower it just falls apart.
I'm running this on XP, on the bare metal (not in a VM) on a very recent dual core laptop with 4G of ram.
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"Are you suggesting coconuts migrate?"
Comments
This should work- I think the reason few have run into this before is that you're using a very high sampling rate to look at a slowly changing signal. At 1uS/div, a 15.9kHz sine will take 62 divisions for one cycle! See attached for a screenshot of a 1MHz sine wave captured at 1uS. This is very stable... (I've marked some items in red)
Hanno
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Co-author of the official Propeller Guide- available at Amazon
Developer of ViewPort, the premier visual debugger for the Propeller (read the review here, thread here),
12Blocks, the block-based programming environment (thread here)
and PropScope, the multi-function USB oscilloscope/function generator/logic analyzer