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VCXO and XO for 64b66b


For the first generation 64b66b prototypes we're most likely going to 
use existing SONET mux/demux chipsets. Thus the CMU is a times 
16 or times 64.

This means that the reference clocks most be 10.3125GHz/64 = 
161.1328125MHz (or 644.53125MHz).

These are non-standard frequencies for most XO and VCXO 
manufacturers, and the lead time is in the 3 months range. Thus, if 
we don't want the 64b66b prototypes to be delayed 3 months due to 
lack of oscillators, someone (e.g. a group of module and systems 
vendors) should get the oscillator guys started.

In a future mux/demux chipset customized for 64b/66b the CMU 
could be times 66 or times 132. Thus, then you will need 156.25MHz 
or 78.125MHz XO's and VCXO's. These are also non-standard 
frequencies. But then again, you might not want this when you have 
already paid for your custom 161.13...MHz oscillators.

This is a very real problem for the standard effort. We need these to 
demonstrate solution, and we have a very tight schedule.

So, is anyone willing to pay NRE to an oscillator manufacturer to get 
this started, or should we as a group invite some oscillator 
manufactorers to join the IEEE P802.3ae, and hope they will be 
tempted by the potential profits?

Henning Lysdal

Mileparken 22, DK-2740 Skovlunde, Denmark
Tel: +45 7010 1062, Fax: +45 7010 1063
Direct: +45 44546 154
e-mail: hl@xxxxxxx,