[sdiy] oscilloscope single/dual ?

[Magnus Danielson]

From: Scott Gravenhorst <music.maker at gte.net>
Subject: Re: [sdiy] oscilloscope single/dual ?
Date: Mon, 28 Jun 2004 15:15:14 -0700
Message-ID: <200406282215.i5SMFEi13743 at linux6.lan>

> Magnus Danielson <cfmd at bredband.net> wrote:
> >From: Scott Gravenhorst <music.maker at gte.net>
> >Subject: Re: [sdiy] oscilloscope single/dual ?
> >Date: Mon, 28 Jun 2004 14:56:49 -0700
> >Message-ID: <200406282156.i5SLuni18760 at linux6.lan>
> >
> >Scott,
> >
> >> I've had both dual and single trace scopes.  Dual wins by a goodly
> >> margin.  Some things can be done with add/subtract, others are not so
> >> easy.  Plus the add/subtract is built in on a decent dual trace, plus the
> >> ability to trigger off of either channel.  
> >>
> >> If this is a democracy, I vote dual.
> >
> >Dual trace or dual channel?
> >
> >There is a difference you know... ;O)
> 
> Actually, I didn't.  What is the difference?  

The difference is that in a Dual trace you have two electron-beams where as in
a standard dual channel you have one electron beam and alternate between them.

> Also, how can one implement dual trace without two input channels?  

Correct, a dual trace has two channels in... at least. One channel per trace is
classic, but you can alternate or chop as you pleases individually for each
trace/beam.

> What I mean, is two separate input channels where each channel can either be
> selected as the sole displayed trace, or both can be displayed as separate
> traces in either alternate or chop mode, or the two input channels can be
> either added or subtracted and displayed as one trace.  Is that dual channel or
> dual trace?

I think I answered that already. With the key-information I'm sure you'd put
two and two together! ;O)

Actually, things are even more complex, since if you have meet a Tek 547 (a
classic tube single beam, dual time-base scope) you'd also know that the Tek
547 has a "Trace Separation" knob. In the double time base mode the Tek 547
alternates between the time-bases and now with that knob you can separate the
time base variants. This is wonderfull to use when you use one of the time
bases as the zoom-time-base of the other time base view. When you as I do have
the 4-channel module (>50 MHz BW a channel), you have a really wonderfull tool
that took many years to surpass in digital.

Oscilloscopes are wonderfull tools, just as you *thought* you knew it all,
there is something new to learn. I could give you more little storries... ;O)

Cheers,
Magnus