8 Nov
1998
8 Nov
'98
11:20 p.m.
>> I definitely notice the 50Hz vs 60Hz
difference on my computer.
> It is visible when using a still picture like a computer
> output.
Well, I can see the 50Hz flicker when running demos,
too. It's not just
because the picture is stable.
Of course, I also have 60Hz lights. When running European software I'll
often shut off the lights and I notice the flicker less.
Maybe this adds some interferences - but are you shure you
had 50 Hz display, or a 50 to 60Hz full screen conversation ?
Often they just add pictures wich results in a strange effect
giving a kind of cartoon feeling.
> 60 Hz gives a more stable view, but on the other
> hand, the poor NTSC coulour signal just damages the view
> again, so again the result is bas - taking this and the
> lower resolution (less horizontal and vertical lines in NTSC)
> I'll prefer the flicker.
Less horizontal lines? Televisions are analog
horizontally, and all of
the computers I know of generate the same number of pixels horizontally
whether they're in Europe or North America.
Shure, they are analog, but still a real world application.
And every signal needs time to rise and fall. And since
analog isn't digital (in fact nothing is digital in real
world), the signal has to go from black to white thru
all shades inbetween (and all shades will be transmitted :).
Only a digital signal could go from blac to white without
any delay - but as I said before the world isn't digital
even digital signals are analog and need their time between
their levels.
Within the 5MHz (b&w) BAS video signal (transmitted withing
the 7 or 8 MHz chanal) the shortest black to white and back
transition (one line) is withing 0.2 us witch gives some
310 theoretical lines within one screen line (horizontal).
But such a signal would be displayed as some kind of gray.
The real resolution within a b&w signal is often less than
250 lines on a real screen.
> THe best was still using PAL with
> 60 Hz - some homecomputers of the 80s could be programmed
> for that - less flicker and high resolution and biliant
> (or at least as briliant as a narow band colour signal
> can be) colours.
Certain European Amiga models would be able to
generate 60Hz PAL. I don't
know what else could, but I've never come across a European computer.
Same for Atari STs and AFAIR C64s, almost all MSXes...
>> I might
>> not notice it with a TV signal, though - I've never watched PAL
>> television. (But I've watched 50Hz 'EuroDemos' on the TV.)
> EuroDemos ? Whats that ?
Demonstrations of music, special effects, artwork,
etc, done on the
computer. Part of C64 and Amiga culture. Called either 'demos', or
'Eurodemos' because they're usually written by European demogroups and
Oh, nust a missunderstanding - I thought about some
kind of demo show on TV.
they often completely fail to run on 60Hz screens. (I
think they take
pride in making their programs not work on North American computers.)
Maybe the same ignorance as US programmers have for any spot
outside their littele hometown ? Serious, these demos are
so tight packed with the FBAS / TV timeing that changing any
parameter just kills funktion, especialy on the C64. If you
want to manipulate scrren colours within a screen line (hor.)
the CPU cycles are just attached to the colours, content and
FBAS timing. And a screen line (hor.) in PAL is about 62.5 us
while a NTSC line is 57us (AFAIR). So, PAL allowes up to 3
additional 6502 operation to be performed within a line.
These demos are sometimes real tight ...
There are still demoparties in Europe with prizes for
Amiga and C64
entries.
Shure - they are BIG events - sometimes several hundred
participants.
I used an SONY
TV for the ATARI ST, 10 years ago.
My brother used a Sony TV for his C64. Which
kind of sucked because it
only had composite input.