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Re: PLL Phase noise and SSB



That would be a record if he can acheive it. There may be problems
eliminating 1/f noise which is usually -140 to -160 dBc/Hz at that offset. I
don't know if the 1/f noise will decrease with temperature or not.

73,

John
KD6OZH

----- Original Message -----
From: "Murray Peterson VK2KGM" <vk2kgm@ihug.com.au>
To: "John Stephensen, KD6OZH" <kd6ozh@AMSAT.Org>; "AMSAT-BB"
<amsat-bb@AMSAT.Org>
Cc: "Pat Leeper" <patleep@mail.bigpond.com>; "Mathew Magee"
<mmagee@sia.net.au>; "Murray Peterson" <murrayp@ihug.com.au>
Sent: Friday, 12 January 2001 07:47 UTC
Subject: Re: [amsat-bb] PLL Phase noise and SSB


> Hi John and everyone else,
>     I have been "out of town" at a Answers In Genesis conference this week
> and I have just got back and found 378 emails so I might be a bit slow at
> replying for a while.
>
>     Of more interest to this group, I meet a Physicist (from University of
> Western Australia) who say he has built the most stable X band oscillator
in
> the world which he is using as part of the most accurate clock in the
world.
> It is a dilectric resonant oscillator! However, the dilectric is a large
> synthetic saphire crystal 50mm diameter and 30mm thick and it is
maintained
> at 6 degrees kelvin (-267 degrees C). Saphire has a dilectric constant of
> about 10. It has an unloaded Q of about 30,000,000! It has at 1 kHz offset
> phase noise estimated to be -165 dbc (No currently available instrument in
> the world can accurately measure it!) He is building a second one of these
> oscillators to incorperate into a measuring insrutment so the phase noise
> can be accurately measured. The frequency stability is 1 part in  1.26 x
> 10^16 or about 0.000001 Hz (one millionth of a Hz - I suppose that is 1
> micro Hz) at 10 GHz!
>
>     He is planning to build several of these clocks for us in time
dilation
> experiments. He is intending to build one of these clocks which can be
> installed on the ISS using a radiator system on the darkside of the
> spacestation to operate a version of these DROs at about 50 degrees Kelvin
> (-223 degrees C). The motion of the spacestation will produce a measurable
> time dilation with respect to clocks on the ground.
>
>     While at about $200,000 each I don't supose there will be too many
> amateur radio operators who could afford this type of DRO but the same was
> probably said about cyrstal oscillators not so many years ago.
>
> Regards,
> Murray Peterson
> VK2KGM
> Sydney, NSW, Australia.


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