Re: 7B71 time base jittering at 50ns/div, but not other speeds.


 

On Wed, Apr 17, 2019 at 01:05 AM, John Griessen wrote:


That is not normal, is it?
Oh yes, it is absolutely normal. The slope should be much steeper for measuring pulse widths or slopes: Consider the fact that with your setup a minimal difference in trigger voltage means a relatively large difference in time. As a result, you're mostly "measuring" trigger voltage. With a steep slope, the trigger voltage is not as critical.
The "jitter" that you're seeing in the slope is a result of the fact that even an extremely small variation in trigger voltage (nothing is perfect) causes a horizontal shift of the image. Adjust the trigger voltage very carefully and you'll see the trace (slope) shift horizontally. The jitter will be less with some settings.

Raymond

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