Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my opinion
that the rendition of skin tones, which we previously agreed was a good test
of a colour display's performance, was actually nothing like as good. Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of, claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display
is extremely impressive, and at this point in my evaluation, far outweighs
any display-quality aspects being claimed for it ...

Arfa

Arfa Daily wrote:

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and vertical
sync, which is very different.


Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Mr. Mendelson has little understanding of how digital television works.
Rather than refute his points, I will urge him to find a book on the subject
and read it.

William Sommerwerck wrote:
Mr. Mendelson has little understanding of how digital television works.
Rather than refute his points, I will urge him to find a book on the subject
and read it.

Actually I do. Why don't you refute my points and that way I can refute yours
instead of this becoming a ****ing contest.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

"Geoffrey S. Mendelson" wrote in
message ...
William Sommerwerck wrote:

Mr. Mendelson has little understanding of how digital television works.
Rather than refute his points, I will urge him to find a book on the
subject
and read it.

Actually I do. Why don't you refute my points and that way I can refute
yours
instead of this becoming a ****ing contest.

First of all, your description ignores the compression systems used, and
treats digital TV more or less as if it is little more than a sequence of
digitized samples. It isn't.

I'm not sure why he makes a point about the lack of sync pulses, as their
lack is implicit in the way compressed video is stored and reconstituted.

"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:


Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my opinion
that the rendition of skin tones, which we previously agreed was a good test
of a colour display's performance, was actually nothing like as good. Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of, claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display
is extremely impressive, and at this point in my evaluation, far outweighs
any display-quality aspects being claimed for it ...

Arfa



Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are
that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and
vertical
sync, which is very different.


Geoff.


Yes Geoff, I'm aware of all that. I work with the technology all the time.
Did you read the original thread from last week ? We were not discussing the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio. On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what controls
for picture setup are available on this particular set, was that given that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like. If this was the case, it might be
accessible to the customer via the standard controls menu, as something like
"tint" or "hue", and the reason that this particular set (they only had the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread, that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

Arfa

Arfa Daily wrote:
"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:


Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my opinion
that the rendition of skin tones, which we previously agreed was a good test
of a colour display's performance, was actually nothing like as good. Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of, claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display
is extremely impressive, and at this point in my evaluation, far outweighs
any display-quality aspects being claimed for it ...

Arfa



Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are
that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and
vertical
sync, which is very different.


Geoff.


Yes Geoff, I'm aware of all that. I work with the technology all the time.
Did you read the original thread from last week ? We were not discussing the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio. On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what controls
for picture setup are available on this particular set, was that given that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like. If this was the case, it might be
accessible to the customer via the standard controls menu, as something like
"tint" or "hue", and the reason that this particular set (they only had the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread, that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

Arfa

surely the flesh tones are entirely down to the colour settings, ie
background, drive, or hue, colour temp etc. Any 3 channel display
except early LCDs can do a palette including all the usual skin tones.


NT

wrote:
Arfa Daily wrote:
"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:

Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my opinion
that the rendition of skin tones, which we previously agreed was a good test
of a colour display's performance, was actually nothing like as good. Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of, claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display
is extremely impressive, and at this point in my evaluation, far outweighs
any display-quality aspects being claimed for it ...

Arfa


Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are
that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and
vertical
sync, which is very different.


Geoff.

Yes Geoff, I'm aware of all that. I work with the technology all the time.
Did you read the original thread from last week ? We were not discussing the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio. On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what controls
for picture setup are available on this particular set, was that given that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like. If this was the case, it might be
accessible to the customer via the standard controls menu, as something like
"tint" or "hue", and the reason that this particular set (they only had the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread, that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

Arfa

surely the flesh tones are entirely down to the colour settings, ie
background, drive, or hue, colour temp etc. Any 3 channel display
except early LCDs can do a palette including all the usual skin tones.

You would think so really, but going back to film photography, there are
reasons why portraits were always shot on e.g. Konica, landscapes on
Agfa or Fuji, , and no one used Kodak at all professionally - Except for
Kodachrome..


NT

You would think so really, but going back to film photography,
there are reasons why portraits were always shot on eg, Konica,
landscapes on Agfa or Fuji, and no one used Kodak at all
professionally -- except for Kodachrome.

No one? Kodak sold -- and still sells -- professional color-negative film
that's often used for wedding photography. In fact, GYF recently introduced
an ultra-fine-grain professional color-negative film. If there weren't a
market for it...

I should tell you that, when I use color-negative film, it's Fuji. Part of
the reason is price, the other is that Costco uses Fuji paper. Fuji on Fuji
produces better results than Kodak on Fuji. (The opposite is also true.)

The Natural Philosopher wrote:
wrote:
Arfa Daily wrote:
"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:

Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my opinion
that the rendition of skin tones, which we previously agreed was a good test
of a colour display's performance, was actually nothing like as good. Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of, claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display
is extremely impressive, and at this point in my evaluation, far outweighs
any display-quality aspects being claimed for it ...

Arfa


Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are
that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and
vertical
sync, which is very different.


Geoff.

Yes Geoff, I'm aware of all that. I work with the technology all the time.
Did you read the original thread from last week ? We were not discussing the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio. On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what controls
for picture setup are available on this particular set, was that given that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like. If this was the case, it might be
accessible to the customer via the standard controls menu, as something like
"tint" or "hue", and the reason that this particular set (they only had the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread, that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

Arfa

surely the flesh tones are entirely down to the colour settings, ie
background, drive, or hue, colour temp etc. Any 3 channel display
except early LCDs can do a palette including all the usual skin tones.

You would think so really, but going back to film photography, there are
reasons why portraits were always shot on e.g. Konica, landscapes on
Agfa or Fuji, , and no one used Kodak at all professionally - Except for
Kodachrome..


NT

Film is a whole nother business. You've got a lot less control over
its 'colour settings' than you have with a display screen, and ditto
re optical linearity. The issues with an LCD screen are quite
different.


NT

wrote in message
...
Arfa Daily wrote:
"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:


Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my
opinion
that the rendition of skin tones, which we previously agreed was a good
test
of a colour display's performance, was actually nothing like as good.
Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and
florid
looking. I also did not think that the black level was any better than on
the other two sets, which is a point that they are making a lot of,
claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness,
contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which
is,
after all, what this is - are set correctly 'out of the box', but I
accept
that this particular one that I saw might not be a good example of the
technology.

I forgot to have a look round the back of it to see if there was a rating
plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the
display
is extremely impressive, and at this point in my evaluation, far
outweighs
any display-quality aspects being claimed for it ...

Arfa



Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that
are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether
or
not thay are interlaced as in 1080i or not. An interlaced frame is
still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are
that
since each frame is discrete, there really is no need for a
syncronization
pulse to define the begining of each frame and more importantly, there
is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Computer displays, BTW are red-green-blue with seperate horizontal and
vertical
sync, which is very different.


Geoff.


Yes Geoff, I'm aware of all that. I work with the technology all the
time.
Did you read the original thread from last week ? We were not discussing
the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs
as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio. On the
example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what
controls
for picture setup are available on this particular set, was that given
that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like. If this was the case, it might be
accessible to the customer via the standard controls menu, as something
like
"tint" or "hue", and the reason that this particular set (they only had
the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread,
that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

Arfa

surely the flesh tones are entirely down to the colour settings, ie
background, drive, or hue, colour temp etc. Any 3 channel display
except early LCDs can do a palette including all the usual skin tones.


NT

The LCD only filters light from the backlight. If you don't have a full
spectrum white in the first place the you can't expect decent colour. White
LEDs aren't quite there yet are they?

Archie

"Archie" wrote in message
...

wrote in message
...
Arfa Daily wrote:
"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:


Well, I saw one of these LED backlit TV sets from Sammy in a store last
night, and I have to say that I was not particularly impressed with the
picture quality. Comparing to conventionally backlit (CCFL) Sony and
Panasonic offerings in immediate proximity to the Sammy, it was my
opinion
that the rendition of skin tones, which we previously agreed was a good
test
of a colour display's performance, was actually nothing like as good.
Both
the Pan and the Sony had a near identical 'tone' to the skin of a
newsreader's face. On the Sammy, that same face was rather pink and
florid
looking. I also did not think that the black level was any better than
on
the other two sets, which is a point that they are making a lot of,
claiming
that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness,
contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which
is,
after all, what this is - are set correctly 'out of the box', but I
accept


P'raps it needs degausing - or the convergence tweaking!

Ahh - my old Dynatron with 27 pots on a hinged panel to play with.


NT

The LCD only filters light from the backlight. If you don't have a full
spectrum white in the first place the you can't expect decent colour.
White LEDs aren't quite there yet are they?

Archie

The LCD only filters light from the backlight. If you don't have a full
spectrum white in the first place the you can't expect decent colour.

Not so. All you have to do is hit the defined points in CIE diagram. The
Pioneer plasma sets hit them dead-on.

The LCD only filters light from the backlight. If you don't have a full
spectrum white in the first place the you can't expect decent colour.
White LEDs aren't quite there yet are they?

Archie


Absolutely true, except that this particular TV doesn't use white LEDs in
its 'revolutionary' backlighting scheme. It uses small RGB arrays, which is
why I was questioning whether there was any control over the individual
elements in each array, such that the colour temperature of the nominally
white light that they produce, could be varied. Which would then, of course,
have a corresponding effect on the displayed colour balance. It just seemed
to me that given they have gone to the trouble of using RGB arrays, rather
than white LEDs, the reason for that might have been to get a full(er)
spectrum white.

Arfa

Arfa Daily wrote:
Yes Geoff, I'm aware of all that. I work with the technology all the time.
Did you read the original thread from last week ? We were not discussing the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

I have no idea of UK law, but in the US and here in Israel, if they use
LED's in the display, then they can call it an "LED TV". I expect the same
in the UK, I was watching a show from the first season of "The F Word" (things
take a long time to get here) and they were discussing exactly what could be
called a sasuage in the UK. Based on what I saw, I expect you would have
trouble fighting them calling a TV with a power on LED an LED TV. :-(



One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio.

In theory, yes they can. Since LCD's have very limited control over brightness
then a variable brightness LED behind an LCD will allow them to modulate the
light level of that particular pixel.

I don't know the resolution of the LCD array used in a TV set, but at the
actual crystal level, it's clear (on edge) or colored/transparent (face out).
I guess if you modulated the polarizing signal you could get levels of color
out of them, but I thought that the crystals were not fast enough for that.


On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what controls
for picture setup are available on this particular set, was that given that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like.

Is there really such a thing as a white LED? The ones I have seen have all
been red/green/blue LEDS on the same substrate to produce what appears to
the eye as a white beam, most of which are far too blue for my taste.

They are blue because blue LEDs have a much shorter life than red and green
so the color will change as they age, and they start out blue before the end up
a red green mix (yellow/orange).


If this was the case, it might be
accessible to the customer via the standard controls menu, as something like
"tint" or "hue", and the reason that this particular set (they only had the
one on display) did not seem to produce good flesh tones compared to the
sets around it, might be because some sales erk had been playing with the
controls to see if he could 'improve' it ...

That may be a different story because PAL TV sets never had them. NTSC
sets needed them because the phase of the color carrier wandered and
often shifted to the green, while PAL sets reset the phase each line and
therefore were always "correct".

Since the chroma signal of an MPEG encoded TV signal does not pass through
a phase encoder unless you connect a composite or RF monitor, it seems
unlikely any sets would have them. More likely, ones sold to people who
are used to PAL over the air signals don't and people used to NTSC ones
do.

Someone - maybe William - commented last week in the original thread, that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

I have yet to be impressed by an LCD/PLASMA TV. Every single one of them
I have seen is oversaturated and too bright.


Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Is there really such a thing as a white LED? The ones I have seen have all
been red/green/blue LEDS on the same substrate to produce what appears to
the eye as a white beam, most of which are far too blue for my taste.

Have you never seen the ones that use a blue LED and a yellow-fluorescent
pigment?


They are blue because blue LEDs have a much shorter life than red and
green
so the color will change as they age, and they start out blue before the
end up
a red green mix (yellow/orange).

What?

I have never seen a dead LED (though I assume they exist), nor have I heard
of LEDs becoming dimmer with age.


That may be a different story because PAL TV sets never had them. NTSC
sets needed them because the phase of the color carrier wandered and
often shifted to the green, while PAL sets reset the phase each line and
therefore were always "correct".

NTSC does not, and never had, an inherent problem with phase stability.


I have yet to be impressed by an LCD/PLASMA TV. Every single one of them
I have seen is oversaturated and too bright.

Because you're seeing them in "torch" mode. There are plenty of good sets
out there. Find a dealer with a Pioneer plasma set, have him put on a really
good disk, and be prepared to die.

"William Sommerwerck" wrote in message
...
Is there really such a thing as a white LED? The ones I have seen have
all
been red/green/blue LEDS on the same substrate to produce what appears to
the eye as a white beam, most of which are far too blue for my taste.

Have you never seen the ones that use a blue LED and a yellow-fluorescent
pigment?


They are blue because blue LEDs have a much shorter life than red and
green
so the color will change as they age, and they start out blue before the
end up
a red green mix (yellow/orange).

What?

I have never seen a dead LED (though I assume they exist), nor have I
heard
of LEDs becoming dimmer with age.


You're not quite correct there. They do dim with age, and that is actually
the way that they are specified for lifetime expectancy. I seem to remember
that it is something like 'hours to the 50% point'. The figure drops
drastically if they are DC driven rather than pulse driven, and if they are
'abused' with excess current. I have also seen dead LEDs in indicators,
bargraph displays, and where they are used as some kind of voltage reference
in amplifier output stages.

Arfa

William Sommerwerck wrote:

That may be a different story because PAL TV sets never had them. NTSC
sets needed them because the phase of the color carrier wandered and
often shifted to the green, while PAL sets reset the phase each line and
therefore were always "correct".

NTSC does not, and never had, an inherent problem with phase stability.

I cant conclude anything, but I know 2 things:
1. NTSC is widely known as Never The Same Color twice
2. The PAL system includes measures to counter phase shift causing
colour issues, so I can only conclude that the system engineers
thought this was a problem with NTSC.

And fwiw, IIUC PAL rendered colours are designed to alternate the
error line after line rather than get each line colour correct, so
like many such measures it usually solves the problem, but not always.


I have yet to be impressed by an LCD/PLASMA TV. Every single one of them
I have seen is oversaturated and too bright.

isnt that just an adjustment thing? And yes, I agree many wont go dim
enough, but some do.


NT

"Geoffrey S. Mendelson" wrote in message
...
Arfa Daily wrote:
Yes Geoff, I'm aware of all that. I work with the technology all the
time.
Did you read the original thread from last week ? We were not discussing
the
differences between transport and encoding systems, rather the moral - if
not technical - validity of Sammy advertising this new offering of theirs
as
a "LED TV", which it isn't. It's an LCD TV with an alternate form of
backlighting (LEDs rather than CCFL).

I have no idea of UK law, but in the US and here in Israel, if they use
LED's in the display, then they can call it an "LED TV". I expect the same
in the UK, I was watching a show from the first season of "The F Word"
(things
take a long time to get here) and they were discussing exactly what could
be
called a sasuage in the UK. Based on what I saw, I expect you would have
trouble fighting them calling a TV with a power on LED an LED TV. :-(


Considering the litiginous nature of U.S. society, and some of the consumer
product cases that William cited in a thread from a few months ago (Canderel
sugar substitute was it ? Something like that anyway) I'm surprised at that.
Also, Ramsay and his sausages is probably more of the exception than the
rule nowadays in the UK. Since handing over the running of our nation in
every way possible to faceless wonders in Brussels, we are so bogged down in
legislation about what we can and can't say about products that we can and
can't sell in ways that they dictate, I'm sure that someone will jump on
this sooner or later to say that unless it's at least 72.65% LEDs, you can't
call it a "LED TV" d;~}



One of the main selling points that they claim, is that because they can
control the intensity of the backlighting in individual areas, they can
deepen the blacks, effectively improving the contrast ratio.

In theory, yes they can. Since LCD's have very limited control over
brightness
then a variable brightness LED behind an LCD will allow them to modulate
the
light level of that particular pixel.


I think that I would have to contest your point of "very limited control".
All of the (recent) half-way decent LCD screens that I have seen to date,
have a perfectly adequate contrast ratio. Certainly, the one in my kitchen
produces deep enough blacks and bright enough whites to be absolutely fine
under the pretty intense flourescent light that I have in there. This is one
of the reasons that I question the requirement to extinguish areas of the
backlighting in order to 'improve' the rendition of blacks.


I don't know the resolution of the LCD array used in a TV set, but at the
actual crystal level, it's clear (on edge) or colored/transparent (face
out).
I guess if you modulated the polarizing signal you could get levels of
color
out of them, but I thought that the crystals were not fast enough for
that.

With HD now, the resolution of the panels is high, and the speed of them is
enough to cope with 100Hz refresh rates



On the example
that I saw last night, I observed no such improvement that was obvious,
compared to the sets around it. The reason that I questioned what
controls
for picture setup are available on this particular set, was that given
that
the backlighting is formed by RGB LED arrays, not white LEDs, then the
overall colour temperature would in theory be adjustable - sort of a grey
scale adjustment for LCDs, if you like.

Is there really such a thing as a white LED? The ones I have seen have all
been red/green/blue LEDS on the same substrate to produce what appears to
the eye as a white beam, most of which are far too blue for my taste.

They are blue because blue LEDs have a much shorter life than red and
green
so the color will change as they age, and they start out blue before the
end up
a red green mix (yellow/orange).



White LEDs do exist in a form that is not RGB based, and in fact is the
commonest form of them. They are blue LEDs with a yellow phosphor overlaid.
There is a wide variety of 'colours' of white available, including ones that
are distinctly bluish, and ones that are yellowish.



Someone - maybe William - commented last week in the original thread,
that
they had seen one in Fry's in the U.S., and that they weren't especially
impressed, either.

I have yet to be impressed by an LCD/PLASMA TV. Every single one of them
I have seen is oversaturated and too bright.


Well actually, the one in my kitchen isn't, neither is the one in my
daughter's lounge. The new Pan that I saw Friday in my friend's shop, was
excellent in that respect, giving an extremely nicely 'balanced' picture.
There are aspects of flat panel displays which cause me to like them less
than CRTs, but 'general' picture quality in terms of brightness, contrast
etc, is not one of them. I think that in general, they've got that one
nailed down now.

Arfa

In article ,
Arfa Daily wrote:
I think that I would have to contest your point of "very limited
control". All of the (recent) half-way decent LCD screens that I have
seen to date, have a perfectly adequate contrast ratio. Certainly, the
one in my kitchen produces deep enough blacks and bright enough whites
to be absolutely fine under the pretty intense flourescent light that I
have in there. This is one of the reasons that I question the
requirement to extinguish areas of the backlighting in order to
'improve' the rendition of blacks.

If you're just watching casually under high ambient lighting, the quality
of the blacks is pretty irrelevant. It's when you're doing some serious
viewing under subdued lighting that it matters. And this is exactly where
ordinary backlit LCD falls over against CRT.

--
*Who is this General Failure chap anyway - and why is he reading my HD? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 22 May 2009 09:24:03 +0000 (UTC), Geoffrey S. Mendelson wrote:
Arfa Daily wrote:

I don't know what 'set-ups' this TV has, in terms of brightness, contrast,
colour saturation, tint/hue, but in my experience, most LCD TVs - which is,
after all, what this is - are set correctly 'out of the box', but I accept
that this particular one that I saw might not be a good example of the
technology.

Based on the assumption that it is a PAL set probably brightness,
contrast, and maybe color saturation. Digital TV sets are not PAL per
se, but they still use the same luminance, color, sync, signals that are
used by PAL (and slightly differently by NTSC).

They are also still 25 or 30 frames per second depending upon whether or
not thay are interlaced as in 1080i or not. An interlaced frame is still
2 fields, at 50 or (almost 60Hz) combined.

The main differences between a digital TV signal and an analog one are that
since each frame is discrete, there really is no need for a syncronization
pulse to define the begining of each frame and more importantly, there is
no color subcarrier.

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Not in the slightest. Do you even understand the difference between digital
and analog? Put a USB signal from a DMM on a scope and compare that to the
input signal and then get back to us how they are so similar.


Computer displays, BTW are red-green-blue with seperate horizontal and vertical
sync, which is very different.
That's analog. Did you never learn that video displays use a video
dac to generate analog voltages for driving an analog monitor?

AZ Nomad wrote:

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Not in the slightest. Do you even understand the difference between digital
and analog? Put a USB signal from a DMM on a scope and compare that to the
input signal and then get back to us how they are so similar.

What has that have to do with what I said?

If you look at the DECODED signal, which would be a stream of numbers,
one defining a luminance level and the other defining a color, and
displayed them using an appropriate method, it would look a lot like an
analog signal displayed the same way.

You are confusing ENCODED data with DECODED data.

Let's take your example, A DMM with a USB output sends out a data stream
of samples. These samples are encoded as numbers, let's say 32 bit signed
integers, stuffed into packets and the packets have USB handshaking and
other data transmission information wrapped around them. Looking at the
USB output of the DMM (which would be ENCODED data) you would see very little
that resemebled the input.

Now if you stripped off all the USB handshaking and control information, and
recombined the packets into a data stream, what would you see? If you used
that for a histogram or "osciloscope display" ala Winamp, the DECODED data
would look a lot like the original signal. (depending upon sampling rate,
etc).

Now, back to the TV signal. Since it an MPEG (any level) encoded stream
contains individual pixels as samples of luminance (brightness) and chroma
(color), if you were to display it as a histogram, let's say vertical lines
being brightness and each line colored according to the chroma (color),
then if you did the same thing to an analog signal, they would look
awfully close.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

On Sat, 23 May 2009 23:09:04 +0000 (UTC), Geoffrey S. Mendelson wrote:
AZ Nomad wrote:

If you were to look at a digital TV signal decoded as if it were a
stream of pixels, you would see something that looked a lot like an
analog TV signal.

Not in the slightest. Do you even understand the difference between digital
and analog? Put a USB signal from a DMM on a scope and compare that to the
input signal and then get back to us how they are so similar.

What has that have to do with what I said?

The comment that I quoted with the ridiculously idiotic statement that
digital streams look like analog.


If you look at the DECODED signal, which would be a stream of numbers,
Moving the goalposts? Pathetic.

If you look at the DECODED signal, which would be a stream
of numbers, one defining a luminance level and the other defining
a color, and displayed them using an appropriate method, it would
look a lot like an analog signal displayed the same way.

That isn't the way an MPEG is encoded. It's rather more complex.

Furthermore, as most (though not all) color-encoding systems use some
combination of luminance and color-difference signals, it follows that, on a
basic level, DVDs, BDs, NTSC, and PAL -- not to mention JPG -- are very much
alike. Claiming there's an interesting similarity doesn't tell us something
we don't already know.

I was not impressed with the Samsung "LED" set I saw at Fry's, either. It
looked as if it had been set to "Torch" mode. What it would look like set
for a normal-to-dimly lit room is anyone's guess.