CurtPalme.com Home Theater Forum

[skippyar]

I wonder if someone would be kind enough to clarify a query for me.

I have a Humax FoxSat HD (satellite receiver.) If I converted the HDMI signal from this device
to VGA (HDfury/ et al) so I can connect to my Barco 500 Data via 5 BNC (1024*768 max resolution)

I don't understand how it can be expected to display the video as I'm lead to believe the digital to analogue conversion retains the original image ratio.

So how does a TV channel formatted 1080i / 576i / etc transcend to the Barco's VGA capabilities of 648*480 / 1024 * 768
because if I was to "emulated" a TV resolution via the PC the CRT simply can't display as it's outside of
the prefixed parameters supported.

In the table of projector rankings it states my CRT can support HDTV resolutions 720p, 1080i (HDfury)

Perhaps it is re-scaling the source HDMI for VGA.



Thanks.

(Suprisingly the CRT connected via composite video from the Humax FoxSat HD is pretty damn good.)

[dvh99]

crts dont have a prefixed resolution or a precise max resolution.
its just that when you let the pj run at a too high scanrate the image might go soft.
i dont know the max scanrate on the bd 500 but 1920*1080 at 72 hz is just above 80 khz so if your pj supports that it will display a picture but the picture will have overlapping scanlines and the image will get soft.
a 9 inch lcp tube can display about 2000 lines and a lug tube about 2500.
a 7 inch a lot less of course.

[skippyar]

"The scan rate is controlled by the vertical blanking signal this is limited by the maximum horizontal scan rate and the resolution, since higher resolution means more scan lines."

So basically the capability is dictated by:

horizontal scanning frequency ** kHz at a resolution of 'width × height' results in a refresh rate of **,000 / (height × 1.05) ≈ XX Hz


1.05 = (5% electron scantime).

I think my CRT will manage 48Khz.