Converting component sync

On Fri, 15 Dec 2006 20:39:49 GMT, Dave Farrance
wrote:

Doughboy wrote:

On Fri, 15 Dec 2006 17:54:43 GMT, Dave Farrance:

OK. Seems the TV's more trouble than it's worth, then.

Do some DVI inputs work at 50hz as well then? So when looking at DVI
equipment (eg DVD player), I'd have to make sure it worked on the 525
line/60hz system to be compatible with my TV?

A DVI or HDMI input is indicative of a more flexible chipset, but not in
the case of your TV, it seems. Even if you did buy a dual-standard DVD
player that could output 60Hz, it would only do so with "NTSC" DVDs.

You will only be able to play "PAL" DVDs on that TV via your computer -
and even then you should notice a slight jerkiness because the frame
rates do not convert too well.

I just tried creating custom modes for 480i/720p/1080i at 50hz and the
TV reports that it's in those modes so maybe there's some hope.

Doughboy

Doughboy wrote:

I just tried creating custom modes for 480i/720p/1080i at 50hz and the
TV reports that it's in those modes so maybe there's some hope.

OK. Can you create a custom mode for 576i at 50Hz?

--
Dave Farrance

On Fri, 15 Dec 2006 21:35:58 GMT, Dave Farrance
wrote:

Doughboy wrote:

I just tried creating custom modes for 480i/720p/1080i at 50hz and the
TV reports that it's in those modes so maybe there's some hope.

OK. Can you create a custom mode for 576i at 50Hz?

I created a custom mode of 720x576 at 50hz and the TV reports it's in
720p mode.

Doughboy

On Fri, 15 Dec 2006 15:36:31 GMT, Doughboy wrote:

What exactly do you mean by a composite/s-video standards converter though?
Does is just convert composite to s-video? If so, that does practically
nothing to the signal anyway.

Are you sure that your TV won't work with 50 Hz video? Was it bought in the
USA?

It's a proper Digital Video Converter (made by Com World I think),
that can convert from/to any composite or s-video signal at various
standards. I'm baffled as to why it won't convert my Freeview's
composite signal. The Freeview does have s-video out as well, which
I'll try when I get a suitable lead.

I bought the TV second-hand over here but it was originally bought in
the USA.

As I see others have explained, you would need an enormous amount of
highly complex circuitry to convert between 525/60 and 625/50. Most
domestic "multistandard" equipment only does a partial conversion,
relying on the fact that most European TV sets can automatically
switch some of their circuitry to accommodate.

If your TV is a CRT type, then if you're considering building
circuitry and know what you're doing with the innards of a TV set,
this would be by far the simplest thing to modify. For component
signals, where no colour decoding is required, the only things that
change between standards will be a couple of components in the
vertical scan generator, one to change its natural frequency, and one
to change the amplitude of its output. Autodetecting 50Hz or 60Hz
would be an embellishment, but even that isn't very complicated.

Rod.

"Dave Farrance" wrote in message
...
Doughboy wrote:

Can anyone tell me how easy/hard it is to convert a PAL component
signal to an NTSC component signal.

I think it's just the sync that's different but I could well be wrong.

Stricly speaking, PAL and NTSC are methods of encoding colour onto a
*composite* signal, and do not apply to component signals.

However, as you probably know, PAL tends to be used in 50Hz 576-line TV
systems, and NTSC tends to be used in 60Hz 480-line TV systems, and if
you see DVDs marked with "PAL" or "NTSC", then that is what is meant.

Are you being "ultra precise"? I always thought that we had 625 horizontal
lines, and the yanks had 525.

Sylvain.

What is the actual problem? Have you got a display that can't handle a
50Hz source? The difficulty is that dual-standard consumer equipment
tends to be sold in PAL areas rather than NTSC areas, so it's much
easier to go from NTSC to PAL than the reverse.

--
Dave Farrance

In message , Sylvain VAN DER
WALDE wrote


Are you being "ultra precise"? I always thought that we had 625 horizontal
lines, and the yanks had 525.

Not all the lines carry the picture.

--
Alan
news2006 {at} amac {dot} f2s {dot} com

On Mon, 18 Dec 2006 21:02:08 GMT, Sylvain VAN DER WALDE
wrote:

However, as you probably know, PAL tends to be used in 50Hz 576-line TV
systems, and NTSC tends to be used in 60Hz 480-line TV systems, and if
you see DVDs marked with "PAL" or "NTSC", then that is what is meant.

Are you being "ultra precise"? I always thought that we had 625 horizontal
lines, and the yanks had 525.

We do. It's just that in analogue TV, 50 of them are for field blanking
leaving 575 for active picture (actually 574 and two 1/2 lines).
In digital TV, the 1/2 lines become full lines, making 576.
A similar thing applies to the Yanks' system.

On Sat, 16 Dec 2006 10:28:26 +0000, Roderick Stewart
wrote:

As I see others have explained, you would need an enormous amount of
highly complex circuitry to convert between 525/60 and 625/50. Most
domestic "multistandard" equipment only does a partial conversion,
relying on the fact that most European TV sets can automatically
switch some of their circuitry to accommodate.

I've now tested the converter with the Freeview's S-video out and that
works (although it still doesn't look great) and as with composite
conversion, the TV loses it's ability to detect the correct aspect
ratio. The converter's a Com World CMD-850, which I'm surprised to see
sells for about $240.

I've actually found that my PC's VIVO graphics card does a far better
job, taking PAL composite in and going out to the NTSC TV via DVI. I'm
not sure that it's widely known that these cards can be used in this
way and I've never seen it mentioned.

If your TV is a CRT type, then if you're considering building
circuitry and know what you're doing with the innards of a TV set,
this would be by far the simplest thing to modify. For component
signals, where no colour decoding is required, the only things that
change between standards will be a couple of components in the
vertical scan generator, one to change its natural frequency, and one
to change the amplitude of its output. Autodetecting 50Hz or 60Hz
would be an embellishment, but even that isn't very complicated.

I've just tried the Freeview's Component out to the TV and the
picture's rolling vertically, so it seems this modification will be my
best bet, although I'd have to consider whether it would affect the
other Component in or the DVI in. I'd be very grateful if you could
provide some further information or links to websites with information
on this.

Doughboy

It probably doesn't make any difference, but I was going to mention
that the TV is actually running on [email protected] because as far as I know
the transformer only converts the voltage.

Doughboy

On Wed, 20 Dec 2006 13:03:21 GMT, Doughboy wrote:

If your TV is a CRT type, then if you're considering building
circuitry and know what you're doing with the innards of a TV set,
this would be by far the simplest thing to modify. For component
signals, where no colour decoding is required, the only things that
change between standards will be a couple of components in the
vertical scan generator, one to change its natural frequency, and one
to change the amplitude of its output. Autodetecting 50Hz or 60Hz
would be an embellishment, but even that isn't very complicated.

I've just tried the Freeview's Component out to the TV and the
picture's rolling vertically, so it seems this modification will be my
best bet, although I'd have to consider whether it would affect the
other Component in or the DVI in. I'd be very grateful if you could
provide some further information or links to websites with information
on this.

Can't help with any websites unfortunately, but I can confirm that the
timebase of a CRT monitor will affect everything it displays, from any
input. I can also confirm what you suggest in your other posting, that
the frequency and voltage of the mains is utterly irrelevant.

Depending on the exact circuitry of the vertical timebase, it will
probably only be necessary to make small changes in a couple of
resistor values to alter its frequency and amplitude. If there are
physical potentiometers to adjust these things, this is where to start
looking, and perhaps experimenting with changes in values, but ideally
you should obtain a service manual that shows the circuit in detail.
The physical controls, if they exist, will be marked "V Hold" and
"Height" (or perhaps something like "V Amp").

Rod.