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That state of metric conversion in the US

Maybe because there is no real need? When was the last time you said,
"Gee, I wish my display had more resolution". I was happy with my 1280
monitor and now my laptop has 1440. I can get 1920 on a desktop
display. Do we need more?

You can never have too many pixels (I really liked my 1600x1200 laptop
(in the mid-late '90s).
The sequential RGB might be useful for one of those DLP displays, but I
think they may already be doing that. Do they still make them? I
haven't seen one in a store for a long time now.

DLP? You're kiddin' right? Pretty much every theater on the planet,
at least ones built in the last decade, uses DLP. Most PC projectors
are DLP. <boggle>
 
S

Spehro Pefhany

Jan 1, 1970
0
Tripling the number of pixels per dollar has obvious marketing
advantages at any resolution. I was just wondering why there are no
sequential RGB LCDs around.

I've only seen segment type sequential RGB LCDs.


Best regards,
Spehro Pefhany
 
S

Syd Rumpo

Jan 1, 1970
0
On 27/02/2013 12:21, Martin Brown wrote:

The inch is 10% more than an atto Parsec by pure chance too.

Nearer 18% less, Shirley?

Cheers
 
R

rickman

Jan 1, 1970
0
Why are PC boards OT here? And why wouldn't people be interested in
seeing some actual designs? They don't call it "artwork" without a
reason.

I see why so many people have a problem with you. By "here" I am
talking about this thread. You clearly didn't really read my comment or
you just choose to ignore it in your reply.

Branching, nonlinear thinking. That's where ideas come from. Lots of
people are hostile to ideas.

And isn't a discussion group about discussing things?

Yes, indeed. But a thread is about a given topic and you are very good
at hijacking. You also never trim your posts and there are many other
things about the way you use these groups which makes them less than
pleasant for others. Not the least is the bickering you seem to enjoy
taking part in.
 
J

josephkk

Jan 1, 1970
0
I do design PCBs, but not as art. Most of my stuff is very small and
often very low power. I find that I can make it tiny, I can make it
good, I can make it pretty : pick two.

I thought you were talking about the issue we had been discussing, PCB
software in relation to metric vs. inch. But I guess we are making a
hard left turn... or do you make right turns? I don't recall.

He makes curly-Q turns.
 
J

josephkk

Jan 1, 1970
0
Yes, the 1920 by 1200 display i am using to post this show jaggies on the
"y" and a couple other letters. My best screen so far is 2560 by 1440.
Per dollar? It wouldn't be free. Adding pixel density stops having
value at somepoint and I think going from 100 to 300 pixel per inch has
far passed the useful point.

See above about jaggies. And to think i am slightly sweating losing my
visual resolution.
For a conventional LCD, what is the marginal cost of pixel density?
Anyone know how much it costs to go from 100 pix/in to say 150 or even
120 pix/in?

I wonder just how many transistors per pixel there are? That could have
some impact on the savings and resolution improvement. In any case an LCD
monitor is one hell of a big thin film IC.
I can agree that some small increment in pixel density would have
benefit, but tripling the density would probably exceed the capacity of
the eye to see. I think now a single pixel on my laptop is hard to see
and that is only 18 inches from my eyes. My problem is not that I need
more pixel density, I just need more pixels.

Another wild turn.

?-)
 
J

josephkk

Jan 1, 1970
0
I was beginning to think no one had noticed. The nice part is it
doesn't need batteries. It is gas operated. I don't like pulling the
starter cord though. I have to add oil to the gas, its just a dual
core. My next one will be a quad core, but they weigh a lot more.

Yeah, but the quad core develops its best torque at a bit higher speed.
They are also a bit more cache.

Good one. But the settings were changed and it didn't quite pop off this
time.

?-)
 
J

Jasen Betts

Jan 1, 1970
0
Maybe because there is no real need? When was the last time you said,
"Gee, I wish my display had more resolution". I was happy with my 1280
monitor and now my laptop has 1440. I can get 1920 on a desktop
display. Do we need more?

1920 rows?, yeah, I'd be happy with that. :)
 
F

Fred Abse

Jan 1, 1970
0
Yes, but it doesn't apply to circuit board which is where I care about the
speed of light mostly. Instead it is around 200 mm per ns depending on
your board construction.

So it's 1/sqrt(k) feet per nanosecond.

Or 12/sqrt(k) inches per ns.

Depends on board material, rather than construction per se.
 
R

rickman

Jan 1, 1970
0
You can never have too many pixels (I really liked my 1600x1200 laptop
(in the mid-late '90s).


DLP? You're kiddin' right? Pretty much every theater on the planet,
at least ones built in the last decade, uses DLP. Most PC projectors
are DLP.<boggle>

Yes, I didn't realize that. They just didn't make it in the home TV
market. I guess they couldn't be as flat as LCD and plasma and flat is
"in".
 
R

rickman

Jan 1, 1970
0
1920 rows?, yeah, I'd be happy with that. :)

I'm not sure if it was in this thread hijack or some other place, but
someone mentioned a 1920 x 1200 rather than 1080. I have seen a few
computer monitors in that format, but I would like to get a large format
TV that will let me use 1920 x 1200 for the computer. That would be sweet!
 
R

rickman

Jan 1, 1970
0
Yeah, but the quad core develops its best torque at a bit higher speed.
They are also a bit more cache.

I didn't know that about the quads. I'm fully aware they are more
cache, more than they are worth I'm sure. When I get mine I'll be sure
to keep it rev'ed up to high CPU usages.
 
R

rickman

Jan 1, 1970
0
So it's 1/sqrt(k) feet per nanosecond.

Or 12/sqrt(k) inches per ns.

Depends on board material, rather than construction per se.

Yeah, material is what I meant by construction really. But I think it
does depend (to a second order) on the layup. Stripline and microstrip
are a little different I believe.

Once I dug into some of the details of PCB construction affecting the
electrical features and I found that there doesn't seem to be a good
theoretical basis for the formula used. Most of what I found was
empirical with equations plucked from air to fit observations.

One guy would make some measurements and they would be used as the basis
of PCB design for 10-15 years, then someone else would take some
measurements that didn't agree with the first guy and he would provide a
different set of equations to use that weren't all that much like the
first guy's stuff. In the end I got the impression that none of this is
used rigorously and each board design has to be "tuned" to the vendor's
process. Coupons are often used to verify that the vendor is holding
his process and you are getting what you need.

I haven't done much with tightly controlled impedance so this is not
familiar territory to me.
 
F

Fred Abse

Jan 1, 1970
0
Stripline velocity goes as 1/rootK, but microstrip is part epoxy, part air, so
it's more complex.

True.

Try this, adapted from a Philips (Mullard) research publication of the 1970s.
Ported by me from FortranIV to Fortran77. Dimensions changed from cm to mm.
Stated to run in 2-3 seconds, on an IBM360, runs like lightning on a PC ;-)
I'd be interested to see how it compares with what you use.

Any old F77 compiler will compile it.

* Program for computing the dimensions
* of microstrip couplers using Schwartzmann's
* formulae
*
100 format(20X,'Give data in the following order:'//
+' Relative dielectric constant'/
+' thickness of dielectric in mms'/
+' Thickness of copper layer in mms'/' coupling in - dB'/
+' Center frequency of operation in Hz'/
+' Coupler impedance in ohms'///)
200 format(///' Relative dielectric constant = ',F6.3/
+' Thickness of dielectric = ',F8.5,' mm'/
+' Thickness of copper layer = ',F8.5,' mm'/
+' Coupling coefficient = ',F8.5,' or',F8.3,' dB'/
+' Frequency of operation = ',E10.3,' Hz'/
+' Coupler impedance = ',F8.3,' ohms'///)
300 format(20X,'Number of allowed iterations exceeded'//)
400 format(35X,'Results :'//' Width of lines = ',F8.3, 'mm'/
+' Spacing between lines = ',F8.3,' mm'/
+' Length of coupling region = ',F8.3,' mm (odd mode)'/
+' Even mode impedance = ',F8.3,' ohms'/
+' Odd mode impedance = ',F8.3,' ohms'/)
500 format(1H ,'Width of',F8.3,' ohm connecting line = ',
+F8.5,' mm'/)
write(*,100)
read(*,*)er,h,t,db,freq,z0
x=db/20.0
couple=10.0**x
write(*,200)er,h,t,couple,db,freq,z0
b=376.6/sqrt(er)
d=1.0/(3.0*sqrt(er))
f=1.35/alog(4.0*h/t)
zoe=z0*sqrt(1.0+couple)/sqrt(1.0-couple)
zoo=z0*sqrt(1.0-couple)/sqrt(1.0+couple)
k=1
w=0.0
m=0
step=0.01
8 if(k.gt.1000)go to 1
go to 2
1 write(*,300)
go to 3
2 w=w+step
a=w/h
g=(a+1.0)*(a+1.0)
aa=d*(a-(1.0/g))
bb=d/g
cc=a+aa+0.5*d*a-bb+1.5*f
dd=0.5*d*a+0.5*f
x=((b/zoe)-cc)/dd
y=1.0/x
xx=4.0*(y-1.0)
s=w/xx
if(s)13,13,14
13 teszoo=1.0e10
go to 15
14 zcppu=2.0*aa
m=m+1
zcppud=4.0*d/((s/w)+1.0)
zcdf=1.35/alog(4.0*s/(3.141592*t))
teszoo=b/(a+zcppu+f+zcppud+zcdf)
if(m.eq.1)step=step/10.0
15 check=(teszoo-zoo)/zoo
chabs=abs(check)
if(chabs.le.0.01)go to 4
if(check)5,4,7
if(m.eq.1)step=step*10.0
5 w=w-step
step=step/10.0
k=k+1
go to 8
7 k=k+1
go to 8
4 const=er/(2.998e8*376.6)
cppu=2.0*const*aa
cdppu=8.0*d*const/((s/w)+1.0)
cpp=const*w/h
cf=const*2.7/alog(4.0*h/t)
cdf=const*2.7/alog(4.0*s/(3.141592*t))
coo=cpp+cppu+0.5*cf+0.5*cdppu+0.5*cdf
aloo=1.0/(1.0+((cppu+cdppu)*(1.0-(1.0/sqrt(er)))/(2.0*coo)))
akoo=1.00/sqrt(1.0+aloo*aloo*(er-1.0))
cleng=0.25*2.998e11*akoo/freq
write(*,400)w,s,cleng,zoe,zoo
l=1
w0=0.0
stepj=0.1
9 if (l.gt.1000)go to 1
w0=w0+stepj
a0=w0/h
g0=(a0+1.0)*(a0+1.0)
aa0=d*(a0-(1.0/g0))
tz0=b/(a0+2.0*aa0+2.0*f)
che=(tz0-z0)/z0
cheab=abs(che)
if(cheab.le.0.01)go to10
if(cheab)11,10,12
11 w0=w0-stepj
stepj=stepj/10.0
l=l+1
go to 9
12 l=l+1
go to 9
10 write(*,500)z0,w0
3 stop
end
 
Yes, I didn't realize that. They just didn't make it in the home TV
market. I guess they couldn't be as flat as LCD and plasma and flat is
"in".

No, LCD and Plasma got cheaper and have a wider viewing angle (and all
sorts of other advantages that are useful in the home theater).
 
I'm not sure if it was in this thread hijack or some other place, but
someone mentioned a 1920 x 1200 rather than 1080. I have seen a few
computer monitors in that format, but I would like to get a large format
TV that will let me use 1920 x 1200 for the computer. That would be sweet!

You're not going to find 16:10 TVs, period. That's one of the reasons
PC monitors are being forced into the crappy 1920x1080 format (cost).
There are higher resolution PC monitors (than 1920x1200). Here is a
30" with a 16:10 aspect ratio (2560x1600). Only $1075.

http://www.amazon.com/Dell-UltraSha...=1362420423&sr=1-3&keywords=2560x1600+monitor
 
S

Spehro Pefhany

Jan 1, 1970
0
I'm not sure if it was in this thread hijack or some other place, but
someone mentioned a 1920 x 1200 rather than 1080. I have seen a few
computer monitors in that format, but I would like to get a large format
TV that will let me use 1920 x 1200 for the computer. That would be sweet!

Get a 4K TV wehen they become available and you'll probably be happy.

http://store.sony.com/p/Sony-4K-TV-Ultra-HD/en/p/XBR65X900A
 
J

josephkk

Jan 1, 1970
0
I'm not sure if it was in this thread hijack or some other place, but
someone mentioned a 1920 x 1200 rather than 1080. I have seen a few
computer monitors in that format, but I would like to get a large format
TV that will let me use 1920 x 1200 for the computer. That would be sweet!

Could you settle for 2560 x 1440 in 27 inch or 30 inch format? Both are
available.

?-)
 
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