Olympus-OM
[Top] [All Lists]

[OM] Re: [OT] Help with monitor problem

Subject: [OM] Re: [OT] Help with monitor problem
From: Jez Cunningham <jez.cunningham@xxxxxxxxx>
Date: Thu, 1 Dec 2005 16:28:53 +0100
Chuck,
Let me dig back to my EE days...

On an analog monitor (CRT) the electron beam is deflected in the X and Y
axes by deflection coils (electromagnetic) or plates (electrostatic).  Each
deflection signal is theoretically a sawtooth to move the spot linearly in
one direction and then fly back fast for the next line/frame.  Theoretically
the slope of that sawtooth waveform would have to be dead straight.

Due to non-linearities in the deflection and the need to deflect according
to the screen shape (non-hemispherical) some 'deflection linearity' circuits
are built in to 'correct' it.  And they're not perfect and they can drift.

Goodness knows how this is achieved in modern CRT monitors - probably the
deflection is managed by a D/A converter - but certainly yours ain't right.
Maybe there's a menu control (I've got one on my Trinitron monitor, under
the option set called "geometry" but it only does vertical linearity -
mine's set to 66 fwiw :-) - or maybe there's knob to adjust it inside (you
remember the TVs of the 60's with all those knobs on the back?!)

So there is one advantage of an LCD monitor - the linearity is built in,
pixel-by-pixel....

Not much help, eh?
Jez

==============================================
List usage info:     http://www.zuikoholic.com
List nannies:        olympusadmin@xxxxxxxxxx
==============================================

<Prev in Thread] Current Thread [Next in Thread>
Sponsored by Tako
Impressum | Datenschutz