a beginner question - scopes

[Martin Czech]

> and there we are at the end they say
> (i think i didn't even read that. god bless me)
> - oscilloscope:
> .timebase 100ns to 100ms / division
> .starting source (this is basic french translation, hope u understand what
> it means..i don't anyway...) CH1, CH2, or zero point
> .starting flank/side: up or down
> .Starting level: adjustale by 1/2 division step
> .Interpolation: linear or rounded
> .Marks for U and f
> .Input sensibility: 10mV to 5V/division   (oh my god isn't that too small if
> i need to see CV signals or even outputs from vcos (asm1 talks about 10V
> from vco out)
> .Prestart function (what the hell is that??)
> .True RMS reading (noly CA composant (??)
> .datas format : ASCII

SOME DSO DATA  TABLE SNIPPED

These figures are the usuall ones, allmost every DSO has these features.
But what's really interesting is:

analog bandwidth: some manufactures cheat, high sample rate but low bandwidth
(the preamp gets expensive with higher bandwidth).

display refresh time: if the display needs a second to refresh, you'll most probably
miss seldom events. But these events are the main reason for using a scope.

trigger: how clever is the trigger logic? How many modes does it have?
If I buy a DSO I want the full benefits of the digital world, ie. a lot
of clever trigger modes. Not only rising/falling edge. Conditional trigger,
counter trigger, long trigger holdoff times etc. Otherwise the DSO will
allways trigger in the "wrong" moment, ie. display uninteresting parts
of the waveform.

But I have to admit: PC-DSOs get more and more attractive these days.
But perhaps your soundcard together with cooledit will do most of the audio
DSO stuff? Could be.

You should test scopes not only with pulse and sine signals, that's only for 
bandwidth and pulse waveform distortion. Also try complex
signals, like two sines, CD-player output, signals with noise etc.
Let's see how the trigger will cope with that.
You can create such signals also with your soundcard.


m.c.