[sdiy] Oscilloscope question

[ASSI]

Hi Justin,

On Sunday 21 February 2010, Justin Owen wrote:
> On the 'Time/CM' setting (which sets both traces) I can get down to
> about 0.5 seconds before the trace starts flashing or pulsing
> (sorry - not sure what the technical term for this is) - it's like
> the 'refresh' time/speed is getting slower. At 5 seconds I have a
> dot going across the screen as opposed to being able to see a
> complete waveform or line/measurement.

That's a function of the decay time of the phosphor used in the tube, 
so there's nothing wrong with the scope electronics.  The decay is 
exponential, so you can often make good sense of the waveform by 
looking at the fading trace in darkness.  Cranking up the beam current 
a bit helps, too - but use only single-triggering then.

> So - if I wanted to look at a scope that could display an entire
> cycle or at least more info about lower frequency
> waveforms/signals but with the refresh rate of higher frequencies
> - what sort of specs should I be looking at?

You'd need a memory scope for that, cheapest solution these days is a 
soundcard with DC coupled inputs, a PC and some software - or a USB 
scope.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Waldorf MIDI Implementation & additional documentation:
http://Synth.Stromeko.net/Downloads.html#WaldorfDocs