Show us your square wave

[joeqsmith]

GigaWave with Tektronix S-52 tunnel diode head (<25ps Tr)

https://www.sjl-instruments.com/

Nice, what I would like to see the real time behavior, as 20..80% or 10..90% rise time changes over time

On a LeCroy easy to graph over time as rise f(t).

Better late than never.   Showing the output from the LiteVNA (low cost VNA). 

[joeqsmith]

Showing the risetime drift using the latest software with tracking  enabled.  The Tektronix pulser is very slow.  There is a tradeoff between the drift, amount of and how fast the data is collected and the repeatability.   I would imagine if this pulser had a faster pulse rate, I could collect more data and this measurement would tighten up.   

Still, less than 5ps over a span of 21 minutes.   Also they spec the scope for 40ps typical 80/20.   All of the measurements I have made fall below that.   

***
Also shown after 50 minutes, it is starting to appear gaussian with less than 7ps.