[sdiy] Combining two of my favorite hobbies

[Magnus Danielson]

From: Gene Stopp <gene at ixiacom.com>
Subject: RE: [sdiy] Combining two of my favorite hobbies
Date: Wed, 22 Sep 2004 12:26:01 -0700
Message-ID: <BCD0C6AAF20CEA41903A1284F549D6170B5366 at ixca-ex1.ixiacom.com>

Gene,

> Re: monitor stuff - since I got the same results with both RF-modulated
> composite video over coax AND S-video over S-video cable, combined with the
> fact that the original CRT-based tv worked just fine, made me look
> elsewhere. On the 760 video card there is a 4.43Mhz crystal near the Toshiba
> CXA1145M composite video modulator chip, and no 3.579Mhz crystal anywhere to
> be seen (although there is a 14.318Mhz crystal by the Ricoh RGB chip, divide
> by 4 is 3.570Mhz, but it's almost on the other side of the PCB). After much
> googling I discovered that there are apparently two standards for NTSC - one
> is "NTSC/3.58" and the other is "NTSC/4.43". The common standard for NTSC is
> a color burst frequency of 3.579Mhz and PAL is 4.43Mhz.

He... so you got yourself a 4,43 MHz NTSC signal? Cool! It's not exactly
common as I recall it. There are a few other minor variants of NTSC too.

> So I wonder if the thing is using NTSC/4.43 and the LCD tv doesn't like
> that, but the CRT tv does. I have a plan to examine the PCB further to see
> if my idea is correct. If so, I can maybe swap out the crystal as an
> experiment.

Maybe. The 4,43 MHz NTSC version isn't as well supported as the 3,58 MHz
variant.

> I did try the PAL/NTSC hardware switch on the card (made it worse set to
> PAL) but then Ingo pointed out the hidden software option (which is not in
> the manual, BTW, thanks Ingo!). Another thing to try...

Whee!

> Anybody who finds technical flaws in the above ramblings please feel free to
> chime in - this is definitely not an area that I have any experience in!!!

Welcome to the mystery and imagination of the diverse fields of video
standards!

If you thought that Standard Definition TV (SDTV) was a mess, you haven't
looked under the hood of High Definition TV (HDTV)! It's a bloody mess and pain
all over the place. The few good things we had in the past are lost and all
other things just got worse. :/
Ah well. If we only could get rid of that ridicolous /1.001 it would make life
SOO much easier. Normalize to 25 Hz picture-rate and we are fine. I haven't
decided yeat if interlaced or non-interlaced is the best thing, but interlaced
has its definite drawbacks and the bigest gain in old age is gone with modern
receivers anyway. Sigh.

Maybe it's time to go down the lab and service that Philips PAL colour-balk
generator into good shape and also fixing that PAL Genlock generator that I
got. Hmm... how could I get them locket up to something more stable???

Cheers,
Magnus