[Alan Gouger]

Hey guys


Ive been using my VP50pro with my CRT which allows you to dial in [email protected] and change the porches but I

moved it back to my digital system today. Im now in need of a VP for my CRT again.

I tried the Radiance which allows you to dial in all the necessary numbers but does not allow 72hz.

I was PMing back and forth with Athan wondering if the TV1 allows custom timing @72hz. He plans to do some testing when he can. If anyone else has any experience with the TV1 and would know the answer please me know & If so which model. Im in the market for a dedicated VP for the CRT. Im going to spoil this thing.


Thx.

 

[tse]

This is probably not exactly what you are asking for but if you follow these guides the projector will be happy.


Keep vertical blanking about 5% of the frame time.


1/72Hz = 13.9ms


13.9ms x 0.05 = 700us


So that leaves 95% of the frame time to display 817 lines.


1/72Hz x 0.95 = 13.2ms


13.2ms/817 lines = 16.15us for each displayed line. Horizontal frequency will be 1/16.15us or 61.92KHz.


Allow 20 to 25% of the line time for horizontal blanking. Analog (CRT) displays need their retrace time.


So, 16.15us x 0.25 = 4.04us or 16.15us x 0.2 = 3.23us

Less blanking time means lower pixel clock if projector can retrace in time.


With 25% blanking there is 12.11us to display 1920 pixels. The pixel time will be 12.11us/1920 or 6.31ns. The pixel clock will have to be 1/6.31ns or 158.5MHz.


With 20% blanking there is 12.92us to display 1920 pixels. The pixel time is 6.73ns. 1/6.73ns means pixel clock is 148.6MHz.


If the video source has a max pixel clock of 150MHz the blanking times can make a big difference.


This usually works. Allow 20% of blanking time (h or v) for front porch. Leave 25 or 30% for the sync time and the remaining 50% for back porch. The CRT projectors should like it.


Some projectors may have minimum sync times. For example, the Marquee needs the horizontal sync to be at least 1us or flagging at the top can happen.


Sorry if I'm telling you stuff that you already know and I'm not sure that this even answers your original question.


Scott

 

[nashou66]



Quote:
Originally Posted by tse /forum/post/15400643


This is probably not exactly what you are asking for but if you follow these guides the projector will be happy.


Keep vertical blanking about 5% of the frame time.


1/72Hz = 13.9ms


13.9ms x 0.05 = 700us


So that leaves 95% of the frame time to display 817 lines.


1/72Hz x 0.95 = 13.2ms


13.2ms/817 lines = 16.15us for each displayed line. Horizontal frequency will be 1/16.15us or 61.92KHz.


Allow 20 to 25% of the line time for horizontal blanking. Analog (CRT) displays need their retrace time.


So, 16.15us x 0.25 = 4.04us or 16.15us x 0.2 = 3.23us

Less blanking time means lower pixel clock if projector can retrace in time.


With 25% blanking there is 12.11us to display 1920 pixels. The pixel time will be 12.11us/1920 or 6.31ns. The pixel clock will have to be 1/6.31ns or 158.5MHz.


With 20% blanking there is 12.92us to display 1920 pixels. The pixel time is 6.73ns. 1/6.73ns means pixel clock is 148.6MHz.


If the video source has a max pixel clock of 150MHz the blanking times can make a big difference.


This usually works. Allow 20% of blanking time (h or v) for front porch. Leave 25 or 30% for the sync time and the remaining 50% for back porch. The CRT projectors should like it.


Sorry if I'm telling you stuff that you already know and I'm not sure that this even answers your original question.


Scott

Ummm Yeah Right !

I am lost now.

Athanasios

 

[Gary Murrell]

Alan, the Radiance should most certainly allow 72hz at 817p


if you started under a 1920x1080p timing to make the 1920x817p maybe that is the issue because the unit won't do 1920x1080p at 72hz, try starting under another resolution


I am not fimiliar with the Radiance so others will have to chime in, I'd use another Pro Alan

don't want to lose that HD-SDI

-Gary

 

[nidi]

Thanks Scott for your in depth info.



what about full 1920x1080 at 72Hz?


will that put too much stress on the electronics of the projector (Marquee Ultra) ?



my VP has a max Pixel Clock of 165 MHz, and the blanking tiimes


are too small to fix into the 165 MHz limitation.


the picture is not inside the raster and the blanking/sync times cannot be increased so that the picture fits.


is there a way to change the resistors in the circuit to make the picture fit

at [email protected] ??



Thanks



Michael

 

[MadMrH]

TVONE have been tested and run past 180MHz with the new "A" series units.


Then you are half way to blending

(Just pulling your leg)


Great time to but TVONE items from a UK GUY

, as the £/$ is now SO MUCH in your favour..............


Others might be limited to the older 165MHz


All the best, Andy.

 

[tse]

[email protected] will need pixel clock of 179.6MHz if set for minimum blanking times of the projector (400us v retrace/1.8us h retrace).


67Hz is fastest refresh rate that runs w/ pixel clock under 165MHz.


The projector's retrace times are already very short. The designers put alot of effort into getting where it is. There is not really much that can be done to make them shorter.


Scott

 

[MadMrH]



Quote:
Originally Posted by tse /forum/post/15404459


[email protected] will need pixel clock of 179.6MHz if set for minimum blanking times of the projector (400us v retrace/1.8us h retrace).

So TVONE should do that.........

 

[VideoGrabber]

Alana asked:

> Im in the market for a dedicated VP for the CRT. Im going to spoil this thing.

 

[nashou66]



Quote:
Originally Posted by MadMrH /forum/post/15404483


So TVONE should do that.........

Andy, they pushed it to just over 200Mhz!!!!!!!!

Athanasios

 

[Alan Gouger]

I just confirmed with Lumagen this is not possible. I sent them the needed timings and they will try to add it to their list of Fix resolutions when they can, fingers crossed.

Thumbs up to Lumagen for the fast response.


This leaves the VP50pro and the TVone but no one has actually tried this with the TV1 yet.

Here are the numbers needed to pull this off.


H shift 148

H size 1920

H front 88

H sync 44

H back 148

V shift 86

V size 817

V front 4

V sync 5

V back 36

 

[nashou66]

Alan I just checked my lumagen HDQ and from my LG bh100 i output [email protected] and I can output [email protected] 72.


Timing numbers on HDQ:

VTOT:877

VACT:800

VSYN: 5

VFRN: 67

HTOT:2397

HACT:1920

HSYN: 137

HFRN: 11


VRATE: 71.93


Athanasios

 

[zGman]

Thank you Scott !!! CRT man of the year....!


Exactly what we needed, and very timely.


G

 

[Gary Murrell]

Alan, do you have a 2.40:1 screen or 2.35:1? get out the tape measure and check the exact viewing area dimensions


if 2.40:1 you need to use 1920x800p

-Gary

 

[Alan Gouger]

Athan thanks for taking the time to try this. Ill have to dig out my HDQ. Glad I did not sell it when I up graded to the Radiance

 

[VideoGrabber]

Alan I'm confused. I suggested Lumagen, and you wrote:

> I just confirmed with Lumagen this is not possible.

 

[Alan Gouger]



Quote:
Originally Posted by VideoGrabber /forum/post/15410043


Alan I'm confused. I suggested Lumagen, and you wrote:

> I just confirmed with Lumagen this is not possible.

 

[nashou66]

I actually had the wrong timings, i just went down and played some more, updated timings to follow soon.


Ok here are the timings in a snap shot from my Lumagen HDQ. sorry for the blur(no tripod).

Just noticed i put the wrong pic up next, it should have been 800p pic, i deleted the right one by mistake

you can probably play around with the Htot and Vtot and the other ones as well, I messed around for about an hour, you will also have to set your vertical size on your PJ to 0 and i had to mess around with the lumagens posistion and HSYN , aslo set in the output aspect ratio to 2.35, then if your showing a 16x9 in the 2.35 screen you hit the arrow keys up or down to go to 16x9 and it srinks it in on the sides.

Quote:
Originally Posted by alan /forum/post/0


Hey Gary, 235:1. 817 should be correct. By the way thank you for your help behind the scene.

I did 800p as its easier to get geometry perfect, i couldn't get 817 right but you may have better luck.


Athanasios

 

[Alan Gouger]

These timings did not work for me. I do not know why but the image keeps jumping and disappearing. At times it says V sync out of range. Nothing is easy!


Thanks anyways Athan. Ill mess with it some more to get get to the bottom of this.

 

[nashou66]

most likely alan you need to adjust the phase , one adjustment a little one way will make the image go very dark or jump like you said. I also had to adjust the position on the Lumagen, I'll look for those numbers when i get home, it was a massive move from the defaults horizontal numbers.


Athanasios