600hz sub fields & 100hz

lee667

Distinguished Member
Afternoon all,

Been looking at several plasmas, and all of them appear to have the 600hz sub field. Is this better than the standard 100hz? Are they also 100hz standard but then have the 600hz sub field as well?

I'm a tad confused as didn't know which is best or are they are all 100hz with the sub field. Was also looking at a panny x10 but this doesn't appear to have it. The other models were the samsung ps42b451 and the lg 42pg6000 and 42pq6000.

Will be using the tv for sd tv, blu ray and playing the ps3.

Cheers
 

Monarch

Distinguished Member
This has been a confusing matter to many, including myself, I started a thread a while ago, take a look at it, there's an explanation at page 3 (post 40) - http://www.avforums.com/forums/plasma-televisions/1007203-600hz-lets-get-sorted.html

Basically it has nothing, or at least very little to do with motion like Panasonic are advertising. It has very little to do with 100Hz, and it has a very minimal effect on the actual picture quality.

In effect, with 600 subfields, with a 100Hz source (which is 100 fields) you get 6 sub fields per field. During this field the pixel can only activate and then deactivate (light up and turn off) once. The more subfields you have per field the more accurately you can reproduce colour (with more shades) and pixel noise can be reduced in the process as well. That's what I've got from it anyway.

On the whole though, ignore it, it's pretty meaningless, it's just a big number and a 'hype word' (Hz). Since 100Hz and now 200Hz on LCDs is a huge buying point to the general consumer, the plasma manufacturers wanted to beat this with a bigger number, so they can get away with 600Hz. But not only is 600Hz different (which is why they're also labelled as 100Hz), but these things do different things on LCD and plasma anyway!

EDIT: This is the post, it explains it well, if you can understand it! It took me a few read throughs
This is indeed pure marketing, they needed a large number - they've got it. That this number does not mean anything - doesn't matter, nobody cares. And indeed - we see that everyone is confused now.


Ok, here is how it works:


Plasma screen can indeed only have it's pixels on or off. There is no half-on or something like this.


So, how are different shades being generated?


The answer is simple - for every field, ANY plasma is using a number of subfields. In earlier days e.g. 300 subfields, which made 5 subfields per field (60Hz operation mode).


So, how is the 'luminance' being genearted out of those subfields?


This is done by differnt algorithms, every manufacturer is using their own. Common thing between them is - it is using a modified pulse-width-modulation. Modified, becaue a plasma cell can only be activated once during the sequence of one field.


Assuming 600 Subfields and 100Hz feed, we have 6 Subfields per field.


So, what are valid subfield sequences for e.g. a green sub-pixel?


1-0-1-0-1-0 is not a valid sequence - since, as I mentioned, a cell can be only activated once.


0-0-1-1-1-0 is a valid sequence. Here the cell is activated once at a subfield #3 and is being de-activated at a subfiled #6


How exactly this activatinon/deactivation is being implemented with every panel, e.g. in the middle of the subfiled sequence, at beginning or dynamically, is intellectual property of manufacturers and is not being disclosed.


There are a number of patents existing on this subject matter. The sequence of the subfield activation is important for a level of artifacts like False Contouring or flicker with plasma screens.


As such, number of subfields (e.g. 600) doesn't tell anything. The only important thing is - how many subfields per field are being used.


For example 480 Subfields, but with a 60Hz refresh, is better (8 subfields per field) than 600 Subfields at 100Hz (only 6 subfields per field).


So please just try to ignore those irritating numbers born in the depths of the marketing department, they do not have anything to do with how the picture or movement look like on the screen.

-Alex
 
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lee667

Distinguished Member
cheers for that :) I'm guessing the v10 pannys use the 600hz sub fields then. I just wondered as the 1 they had set up had an amazing picture quality compaired to the 100hz panny underneath it (not sure which 1 that was, might have been a g10). Would love to get a v10 but a tad pricey at the mo lol.
 

Monarch

Distinguished Member
Both the G10 and the V10 have the 600Hz subfield, the X10 doesn't, the S10 has a 400Hz subfield which, as explained in the post I quoted, can be better than 600Hz on the right source. There is very little impact of 600Hz though, I believe that the Panasonics last year actually had 600Hz as well, but the buzz word was 1080p then, and 200Hz wasn't around (apart from when Sony released the Z4500) so there wasn't really anything to compete with, so they didn't bother mentioning it. The process this year has been refined and improved.

If it was the G10 you were comparing to it would no doubt be the THX mode on the V10, if it was the X10 then it would be the THX mode and the super deep blacks which made it look so good. But shop set-ups are always difficult and sometimes impossible to go by
 

nickfrog

Active Member
The 42PQ6000 at around £500 is an excellent product, "despite" the 600hz marketing [Word removed by mod].
Lucky Goldstar all the way.
 
Last edited by a moderator:

Jim Di Griz

Distinguished Member
X10 Id say.

G10 if you want to spend more.

Whats your viewing distance?
 

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