how to troubleshoot?

[harry]

Hi All  (mis me ???)

I'd go with a (gasp) good digital scope, and keep an old analog in reserve
for the times when the digital LIES to you... and you need a sanity check.

A tech said to me:  : found the problem... its switcher noise hittinh the dac.
What Frequency, I asked?  He didn't know so I went to show him...
Measure the period....

Then I noticed that no matter what sweep speed... I got the same number of
noise
pulses on my screen.  Hmmm.... is this REAL....can it BE ???

Analog scope shows... white noise. Digital was aliasing it into a periodic
waveform.

Digital is great for frequency, pulse width, lfo, envelopes... etc.  Roll mode
will let
you see your .001Hz triangle. NO analog will do that.

OTOH: If I had $1000 to spend, I'd get a good analog over a cheap digital !!!

My $.03

H^) harry

Lincoln Fong wrote:

> >>However if you got cash to spend get a digital so u can upload upload the
> results to the pc/mac(now were talking 1000$ range)
>
> I have always used analogue scopes and whilst talking about upgrading the
> other day with a friend he mentioned that a good analogue is sometimes
> better than a digital. I think it was something to do with the quantisation
> causing difficulty taking readings(?). Do you scope afficianados have a
> preference? Its mainly for audio work which may have an influence. My
> current one is 20MHz.
> pc uploading is not necessary.
>
> Lincoln
>
> Ps without wanting to start another acronym bonanza what does AFAIK stand
> for???