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Re: Serial D-1 Jitter



 Reply to:     RE>Serial D-1 Jitter
The biggest culprits for jitter on our end are:

1. CABLE INTEGRITY
This encompasses the physical integrity of the coax. We run both 
8281 and CANARE LV series cable with success, but be careful to 
avoid seemingly harmless things like tight loops.  Anything that 
can cause a reflection at 270mb, will.

2. IMPEDANCE
Use only high-quality 75-ohm connectors- replace any you don't have 
pedigree papers for. Never use cheap connectors, like those twist-ons. 
Make sure your patch panels are also true 75-ohm. I standardized on 
the CANARE connectors and patchfields.

3. P/S CONVERSION
Most of my trouble comes from older parallel devices that are just 
plain less stable (Digiscans and A60s come to mind... wait! how about 
that VideoLab board in my SGI!)

Jitter can manifest itself as things you would never expect to see 
in a digital domain.  For example, we had a devil of a time explaining 
why 2 DVTRs recording the same picture looked different. One had a 
oh so slight shift to magenta- like a misadjusted black balance on 
an NTSC encoder. Reclocking the signal fixed it. Go figure.

-bt

----------------------------
Date: 01-24-96 17:18
To: Topazio, Bill
From: Dave Corbitt

What has been the experience of some of the rest of you with dealing 
with this sort of thing?
Dave Corbitt
MTE/NYC