[sdiy] Scope recommendations

[jays at aracnet.com]

>>
>>> The rigol is slow when the
>>> time base is long
>>

It would be good to get more information here.

I'm not familiar with the Rigol scopes but I'm familiar with the Tek
MSO/DPO/MDO series of bench scopes. I'm just picking numbers out of the
air here since I don't know the instrument, hopefully though it will
make the point.

One thing that maybe a problem is acquisition length. There's a number
of ways to look at things in a scope. We're use to having our time
spec-ed as time/div. Let's think about it as sample rate and the number
of samples you have in an acquisition. If you're acquisition rate is say
1 sample per 1ms and you have a length of the acquisition is 10K samples
it's going to take 10 seconds to do the acquisition and refresh the
screen. Now let's change the acquisition length to 1000 samples. It's
going to get an acquisition every one second and update the screen. So
you need to be a bit smarter about using a digital scope than an analog
one to be efficient with it. Think about how much information you need
on the screen to solve your problem and go from there.

Personally I think both are useful but I just have two analog scopes.
An old dual trace Heathkit and a Leader 100 MHz dual trace. Having
measurements, advanced triggering, computer access and large acquisition
buffers in the digital scopes are great tools. I sure would like to get
a Tek MSO4104 but the $20K+ price tag is pretty much out of the picture.
I ran across a Tek FAE the other day and asked if he new any place to
get a cheap used one. He just sort of smiled and said not many come up
for sale and they hold their value well. I have been looking at some the
of Rigol scopes and they look interesting. Maybe someday.

Careful with that probe Eugene.
Jay S.