[time-nuts] ngTADD-1

[Attila Kinali]

On Tue, 23 Apr 2013 22:08:28 -0600
Kevin Rosenberg <kevin at rosenberg.net> wrote:

> On Apr 23, 2013, at 4:16 PM, Bob Camp <lists at rtty.us> wrote:
> > There are optical links that are better than your typical opto coupler. I have not seen many that are good to -170 dbc. 
> 
> Rather than for a 10 MHz signal, I might prefer an optical link rather than
> differential for a PPS signal. Could you recommend any optical links with
> jitter of about 1 ns?


There should be quite a few fiber optics transceivers and receivers for
780nm and 850nm used for data communications (Fiber GBit for inhouse cabling).
The photodiodes should be all PIN diodes in that area, so fast and hence
low jitter (sub 1ns rise/fall times). For the transmitters, if possible
go for those with laser diodes and modulate them (ie no on-off switching).
This will give you jitter way below 1ns (sorry, don't know any hard numbers).

The usual suspects should carry transmitters and receivers that can
couple directly into fibers.

As for the fiber. If possible (and you can afford it) use single mode
fibers. For short stuff multimode should do as well.

			Attila Kinali


-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin