3Gbps SMPTE 292M compliant SDI interface Gennum Corporation

Simple model of Coax cable loss Gennum Corporation Simple model doesn’t account for dielectric effect – but it’s close enough The important thing to note is that the loss variation is with square root of frequency

Assuming 140m of Beldin 1694 Coax cable this model yields a loss of…….. Gennum Corporation Frequency [MHz] Loss at 140m (1694)[dB] 750MHz (1.485Gb/s) MHz (3.0Gb/s) MHz (6.0 Gb/s)50

Current physical interface SDI chips can be modified to reliably (in real systems) recover up to 30dB of loss and remain within SMPTE 292M specification limits at 3Gb/s Gennum Corporation Experimental work to date however shows that this is about as far as we can go without changing existing standards / specifications The following charts illustrate test results from prototype silicon

Equalizer at 3Gbps,PrN23: Belden UI

140m, Belden 1694

The important points to note however are that cable loss dominates Gennum Corporation Pathological is not the limiting factor AND

In summary Gennum Corporation

A fully standards compliant multi-rate (143Mb/s ~ 3Gb/s) SDI interface over Coax cable could be implemented today Gennum Corporation No new installation practices or infrastructure change required to go to higher data rates 3Gb/s provides a useful ‘building block’ for multi-link interface capable of addressing 2K and 4K 4:4:4 formats

It’s familiar – uses all the existing SDI technologies and techniques we know and love today Gennum Corporation Relatively inexpensive solution – compared to data comm / telecom fiber solutions

Some questions…… Gennum Corporation At 3Gb/s, is backwards compatibility with existing SDI infrastructure more important than forwards compatibility with Fiber Is a 100m interface sufficient ?