From: myers@hpfcso.FC.HP.COM (Bob Myers)
Subject: Re: Scope questions
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 31

> 	If my life depended on it, I'd say that it's a scope that
> 	uses long-persistance phosphor to keep the successive
> 	taces on the screen for some unit of time - "store" them.
> 	Do I get to live?

We'll let you live, but just this once....

There's more to a real "storage" scope than just a long-persistence
phosphor.  Actually, the phosphor ISN'T usually anything special at all;
what makes a storage tube work is a screen placed just *behind* the phosphor,
which becomes charged as the electron beam intially "writes" the trace.
With the trace now written to the screen, a separate low-level "flood"
electron gun keeps the image lit by exciting those areas of phosphor
which are next to the "written" areas on the storage screen.  There are
some problems with this - the resolution is limited compared to a non-storage
tube, and the stored trace tends to "bloom" with time. 

Of course, this is pretty much obsolete technology, done in by the current
digital scopes which use raster-scan displays and keep everything in a
frame-buffer memory anyways.

> / Filip "I'll buy a vowel" Gieszczykiewicz. | Best e-mail "fmgst+@pitt.edu"  \
          ^^^^^^^^^^^^^^^^^^

Ah, yes - from the same people who brought you that amazing new reading
program that's sweeping Eastern Europe: "Hooked on Consonants!" :-)


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   Systems Technology Div.  |those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.
