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MegaDisc 04 (1988)(MegaDisc Digital Publishing)(AU)[m][WB].zip
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PALvNTSC
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2007-12-01
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Amiga video notes
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Ed. note: This article came off A BBS - thanks to the unknown
author. There is a program on the Fish Disks which, when you
run it, will tell you whether or not you've got a true PAL
machine. Ask us if you want it.
Several hardware and software versions of the Amiga have been
distributed in Australia. The differences mainly refer to whether the
machine produces the R.F. (radio frequency), Composite and RGB in
American NTSC format or Australian PAL format.
The differences in the format mean that an NTSC format signal will not
be displayed correctly on a pal monitor or television. this is due to a
number of differences in NTSC and PAL formats, ie:
NTSC format consists of only 200 lines of image data. Pal has a greater
number of lines 256.
The burst of information that contains the colour data required to make
up a colour picture is processed differently in relation to the rest of
the signal.
The frequency at which the signal is generated is also different. This
is also known as the scan rate.
To view an NTSC signal on a PAL RGB monitor will result in a crushed
image taking up only 4/5 of the screen. It will be displayed in black &
white and will roll vertically due to the differences in scan rate.
There are two types of Agnus chips, one that generates NTSC and one
that generates PAL signals. Machines with the Pal Agnus chip should
have the letters PAL following the serial number.
However even though the letters PAL appear after the serial number this
does not nessesarily mean that you have a full PAL machine, the agnus
chip may be PAL but the processing circuits may be NTSC. Why this was
done is anybody's guess.
To test your machine to determine which version you have take a
standard audio cable from your stereo, you know the one that connects
the record player to the amp or the amp to the tape deck or visa versa.
This cable should have two plugs on each end. Take one plug from one
end and plug it into the video out port on the rear of your Amiga
(make sure the Amiga is switched off). Next take the same coloured plug
from the other end of the cable and plug this into the CVBS in port on
the rear of the monitor. Power up and get yourself to the insert
Kickstart prompt, now open the front panel on the monitor to expose the
sound brightness controls etc. Now depress the RGB/CVBS button and see
if the screen continues to give a colour display: if it does then you
have a 1.4 full Pal machine. If you get a black & white signal you
have a 1.3 half PAL half NTSC format machine meaning that you have
the PAL Agnus chip but have the NTSC processing circuits.
Owning a 1.3 machine should cause no bother unless you try to output
your creative talents onto a video recorder in which case you will get
a black & white signal. If this is going to be a problem then you need
an NTSC-PAL video converter, or you need to get a different Amiga...
====================END OF PALvNTSC=================================