[SI-LIST] Re: Digital F-mux
- From: Nagaveeraiah Math <swamycn15@xxxxxxxxx>
- To: steve weir <weirsi@xxxxxxxxxx>
- Date: Tue, 8 Feb 2011 20:48:12 -0800
Thanks
Veeru.
On 2/8/11, steve weir <weirsi@xxxxxxxxxx> wrote:
> David, you will still have to deal with the extra parasitics of the
> trace to and the resistor mounting pad structure on the channel side at
> both ends of the link. In silicon that can be made very small. On a
> PCB it is going to be a lot harder to make that transparent. At low bit
> rates this is not an issue. If you are above 3Gbps and you don't have a
> lot of margin you are setting yourself up for a lot of time getting
> intimate with your 3D field solver. I would look exhaustively for a
> digital solution first.
>
> Steve.
>
> David Palmer wrote:
>> 4K resistor.
>> The OOB operates in absence of link unfortunately.
>>
>>
>> steve weir wrote:
>>
>>> David, the multiplexing isn't the hard part. The hard part is finding a
>>> way to separate the two signal bands without creating a discontinuity in
>>> the channel impedance. If you can make your own silicon it seems that
>>> could be done. I don't have any good suggestions on how to do that with
>>> any existing FPGA at appreciable line rates.
>>>
>>> I think that your life will work out much better if you steal a small
>>> amount of bandwidth higher up in the protocol stack than if you try to
>>> get tricky with the physical layer.
>>>
>>> Steve.
>>>
>>>
>>> David Palmer wrote:
>>>
>>>> Has anybody here ever attempted to multiplex very low edge rate OOB
>>>> signals onto a doubly-AC-coupled high speed serial link to save on
>>>> cable conductors? Did you get fired?
>>>>
>>>>
>>>>
>>>
>>
>>
>
>
> --
> Steve Weir
> IPBLOX, LLC
> 150 N. Center St. #211
> Reno, NV 89501
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>
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>
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