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Old January 3rd 04, 06:38 PM
hnmm
 
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Default Why do monitors flicker on TV?

..

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Old January 3rd 04, 07:40 PM
w4jle
 
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Refresh rate. Your used to seeing a 60 Hz refresh rate (actually two
alternating frames at 30 Hz) on your home TV.

If you go to Europe, you go nuts for the first few days getting used to the
flicker as they use a 50Hz refresh rate.


"hnmm" wrote in message
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Old January 8th 04, 06:44 PM
Brian Potter
 
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"w4jle" W4JLE(remove this to wrote in
:

Refresh rate. Your used to seeing a 60 Hz refresh rate (actually two
alternating frames at 30 Hz) on your home TV.

If you go to Europe, you go nuts for the first few days getting used
to the flicker as they use a 50Hz refresh rate.


What a half correct and half junk science answer!

Yes here in the UK we have a refresh rate of 50Hz on our PAL standard
sets compared to 60Hz on NTSC standard TVs but I can't think why it would
drive you nuts? If that's the case, you should be going mad constantly
when looking at PC monitors, EPOS displays and ATM machines as most have
different refresh rates from 47Hz upwards!

The reason is correct as at the top - refresh rate or more a sync problem
- when a computer monitor is 'filmed' but the camera used is not
'synced' to monitor's refresh rate, you see the monitor at one rate being
filmed at another - hence a mismatch.

Really the camera operator should lock the scan rate of the camera to the
refresh rate of the monitor, then both are at the same rate and you get a
steady image with no flicker!

Simple as that and now pretty much a feature on most professional video
cameras.

Brian.
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Old January 8th 04, 07:28 PM
Richard Clark
 
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On 8 Jan 2004 18:44:20 GMT, Brian Potter wrote:
- when a computer monitor is 'filmed' but the camera used is not
'synced' to monitor's refresh rate, you see the monitor at one rate being
filmed at another - hence a mismatch.


Actually, the correct term is "beat."

73's
Richard Clark, KB7QHC
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Old January 8th 04, 08:08 PM
w4jle
 
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It drives me nuts, because at the 25 Hz frame rate I can see the flicker.
After a few days in Merry Ole', I get used to it and don't notice it.

Every trip back to England requires a day or so to get my brain to ignore
the flicker. The other monitors you refereed to do indeed have 47 Hz refresh
rates, but they are non-interlaced video.


"Brian Potter" wrote in message
...
"w4jle" W4JLE(remove this to wrote in
:


Yes here in the UK we have a refresh rate of 50Hz on our PAL standard
sets compared to 60Hz on NTSC standard TVs but I can't think why it would
drive you nuts? If that's the case, you should be going mad constantly
when looking at PC monitors, EPOS displays and ATM machines as most have
different refresh rates from 47Hz upwards!





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Old January 8th 04, 10:08 PM
Nick Smith
 
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and the persistence (?) of the tube will play a part in perceived flicker !!

Nick


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Old January 18th 04, 11:56 AM
Volker Kerkhoff
 
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w4jle wrote:

If you go to Europe, you go nuts for the first few days getting used to the
flicker as they use a 50Hz refresh rate.


If a european ever goes to the US or far east he'll posibly go nuts over
one of the main features of the NTSC color system, AKA as "Not Twice
Same Colors"

;-)

73,

Volker

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Old January 19th 04, 01:07 PM
Editor-GilbertNews
 
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I would agree with that. Once I am use to the flicker, I marvel at the
cnsistancy of color from camera to camera.

"Volker Kerkhoff" wrote in message
...
w4jle wrote:

If you go to Europe, you go nuts for the first few days getting used to

the
flicker as they use a 50Hz refresh rate.


If a european ever goes to the US or far east he'll posibly go nuts over
one of the main features of the NTSC color system, AKA as "Not Twice
Same Colors"

;-)

73,

Volker



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Old January 18th 04, 09:18 PM
Ian Jackson
 
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In message , Volker Kerkhoff
writes
w4jle wrote:

If you go to Europe, you go nuts for the first few days getting used to the
flicker as they use a 50Hz refresh rate.


If a european ever goes to the US or far east he'll posibly go nuts
over one of the main features of the NTSC color system, AKA as "Not
Twice Same Colors"

;-)

73,

Volker



Not really true, surely?

There is 'something' about NTSC compared with PAL. However, I've never
seen bad colo(u)r on NTSC sets which was not mainly due to poor signal
quality anyway, and where PAL would probably been the same.

These days, don't they transmit the correct colours as a reference in
the vertical interval, and the set uses (or can use) this to correct the
phase errors?

Ian.

--

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Old January 19th 04, 03:37 AM
Mike Coslo
 
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Ian Jackson wrote:
In message , Volker Kerkhoff
writes

w4jle wrote:

If you go to Europe, you go nuts for the first few days getting used
to the
flicker as they use a 50Hz refresh rate.



If a european ever goes to the US or far east he'll posibly go nuts
over one of the main features of the NTSC color system, AKA as "Not
Twice Same Colors"

;-)

73,

Volker



Not really true, surely?

There is 'something' about NTSC compared with PAL. However, I've never
seen bad colo(u)r on NTSC sets which was not mainly due to poor signal
quality anyway, and where PAL would probably been the same.

These days, don't they transmit the correct colours as a reference in
the vertical interval, and the set uses (or can use) this to correct the
phase errors?


It is a source of great amusement to listen to people dissing one or
the other - NTSC or PAL, or even SECAM.

They all suck very much. Trying to decide which one sucks the most is a
waste of time.

- Mike KB3EIA -





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