[time-nuts] low noise 8.4 GHz LOs RE: New to the list...Hello from Melbourne

Lux, James P james.p.lux at jpl.nasa.gov
Sun Aug 31 18:36:23 UTC 2008


________________________________________
From: time-nuts-bounces at febo.com [time-nuts-bounces at febo.com] On Behalf Of Stan, W1LE [stanw1le at verizon.net]
Sent: Sunday, August 31, 2008 5:58 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] New to the list...Hello from Melbourne

Hello Clint,

Welcome to the group.

For the accurate (stabilized) LO for the 8 GHZ receiver,

consider the new product offering from   www.downeastmicrowave.com

They are offering a synthesized LO that uses a 10 MHz external reference.

Also consider the    www.n5ac.com   product offering for a USB/PC
programmable microwave LO.
May be more appropriate for 8 GHz. Can be programmed to use a 2-26 MHz
reference.


-----------
I think these are basically the same thing (at least the DEMI site talks about their A32 as being designed by N5AC, and the picture looks identical)

This is also basically a 1.x GHz  synthesizer, to get up to 8.x, you'd need to multiply it up (which DEMI sells stuff for).  The question might be about which scheme is overall best:

a PLL locked source with a VCO at 1-2 GHz multiplied up
a VCO source 8GHz locked to the reference, either directly, or after being mixed down
For either, whether you divide the RF down before running it into a PFD, or if you use a SPD at the RF frequency
And, I suppose, direct multiplication through a bunch of steps (or in one fell swoop with a comb generator and a filter)

Probably depends on your specific needs, in terms of tunability, noise close and far, and power consumption.  It's not something which is cookbook, or for which you can just go look up the equations for all the topologies and trade it off.  (or maybe it is.. there might be some recent text that sort of covers them all)

Jim Lux








Pricing is cost effective for a ham.
Phase noise performance, though not spectacular, may be quite workable.

Stan, W1LE    FN41sr    Cape Cod





Clint Jeffrey - VK3CSJ wrote:
> Hi everyone,
>                  Not sure how many folks there are associated with the "time-nuts" list but hi and hello from Melbourne Australia, I've just signed up a couple of days ago and have already been seeing a degree of activity....all very good.

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