Ralph Mowery wrote:


If I did not post it, the scope is a Hantek dso5202p which is a 200 MHz
scope and a 1 GB sample rate if only one Chanel is use. It does the sin
(x)/x thing to smooth the curve between points. The scope may blow up
but for the money it seems to be a very nice hobby scope. Bought it new
for only $ 299 from a company in the US. It does have a 3 year warranty
I feel safe with it.

I am retired now and just thought it would be nice to play with a
digital scope. I am now finding out some of the limitations of them.
Glad I still have an old Techtronics 465B analog. Seems that going to
the X-Y display is not very good either if I want to compare 2 signals
that are very close in frequency. Never could get the circle to show up
and rotate slowly.



** Nothing approaches using an analogue scope with Lissajous figures - and you can make very complicated and rather pretty ones too with the help of some phase shift networks.

Back in the 1980s I needed to check the AC supply frequency to see how it varied and not having a period counter I used my scope in X-Y mode. I also had a valve audio generator with very fine frequency adjustment ( due to the use of a 30:1 reduction drive on a large tuning gang ) and a regular frequency counter.

Producing a nice circle was dead easy but only resulted in an +/- 1 Hz precision due to uncertainty with the last digit on the counter. So I set the generator to 500Hz and steadied the pattern, giving me 0.1Hz resolution on the counter. Next I tried 5kHz and that gave me 0.01Hz accuracy - going any higher proved impractical.



..... Phil