MultiScree
Channel
Memo
MultiScreen Channel Pty Ltd
353 Cross Road • Clarence Gardens
South Australia • 5039 • Australia
Telephone:
+61 8 8371 4744
Facsimile:
+61 8 8371 4733
Email:
Web:
www.multiscreen.biz
No:
071104
Title:
Video Level Settings
Date:
15/11/07
©2007 MultiScreen Channel Pty Ltd
Note:
For general release
Rev:
1
Page:
1
/
1
Instructi
ons
Author:
MP
VIDEO CARD LEVEL SETTINGS & WISI MODULATOR ADJUSTMENTS
In some circumstances, the use of WISI OV36 RF Modulators with some MultiScreen Channel
Production Units results in a distorted picture on some TV sets, when showing some pictures
with bright backgrounds. This may be alleviated by adjustments to the Brightness and Contrast
settings of the video card in the Production Unit, and by adjusting the Video Gain of the
modulator.
IDENTIFYING THE PROBLEM
The MultiScreen Channel system displays a continuous
loop of individual “screens”, which may
contain a graphic or plain background, static and scrolling text. The problem tends to appear
when displaying bright pictures, especially with large amounts of white background. Symptoms
may include tearing or rolling pictures, horizontal streaking, and audible buzzing.
Different TVs will react to different degrees. It may be useful to find a TV which is readily
accessible and which is more strongly affected by the problem. It would also be useful to
identify screens in the display sequence which are more severely affected. A method of
displaying an individual screen is described later.
The relevant WISI modulator should also be located. WISI OV36 modulators (and the
equivalent OV35 mono version) are mounted in an OV50 Topline Headend frame. This is about
440mm (W) x 400mm (H) x 210mm (D), and may be located in a Communications cupboard or
plant room. Other WISI models and other brands of modulators may also be affected, although
these notes do not cover adjustment methods. If there are a number of modulators in the rack, it
will be necessary to determine which one is handling the MultiScreen Channel. This could be
done by tuning a nearby TV to the MultiScreen Channel signal, then temporarily disconnecting
the video input signal from each modulator in turn, until the MultiScreen Channel picture is lost.
The video input connector is the front BNC connector on the top of the modulator. Note that it
may take a while for the picture to stabilise after reconnecting the
video signal if the modulator’s
Video Gain is set to Auto.
In the following notes, those familiar with the operation of the MultiScreen Channel system may
be able to follow the steps by the brief initial description. The additional text [in square brackets]
provides further detail for those unfamiliar with the procedures. Keyboard keys and modulator
button names are shown in bold italic
Roman
, on-screen buttons or menu selections etc. appear
in
Arial
, screen titles are in
Century
, and socket names are in
Gill Sans
.
ADJUSTING BRIGHTNESS AND CONTRAST
1. Access the
Sequence Editor
. [With the system running normally, either click the left and
right mouse buttons simultaneously, or else press the
Esc
and
Pause/Break
keys
simultaneously. This should break out of the display mode into the
Sequence Editor
.]
