[time-nuts] Dual Mixer
EWKehren at aol.com
EWKehren at aol.com
Tue May 11 18:00:34 UTC 2010
ws
there is no NIH here, please share how you do it for $ 10, I always like to
learn, and I have not been a member that long. Is there a link to a
specific design? Thanks Bert
In a message dated 5/11/2010 1:47:15 P.M. Eastern Daylight Time,
warrensjmail-one at yahoo.com writes:
For the Really cheap time nuts,
It sounds like Bert Kehren has done a great Job building a Dual Mixer
tester.
There are other simpler, less standard ways to get good data for Allan
Variance and small frequency differences.
My VERY simple $10.00 analog tight PLL Tester BB (Previoulsy posted)
pretty
much accomplishes the same goals as his,
and it can do 1e-13 in a second, and 1e-11 in 10ms (limited of course by
the single reference Oscillator used)
A simple test that most can do at home, and still challenges the best high
end testers out there is Tom's the swinging Oscillator test.
http://www.leapsecond.com/pages/10811-g/
(The results from my PLL tester is attached)
ws
******************
----- Original Message -----
From: <EWKehren at aol.com>
To: <time-nuts at febo.com>
Sent: Tuesday, May 11, 2010 7:02 AM
Subject: [time-nuts] Dual Mixer
> The Dual Mixer project is nearing completion.
> Let me refresh every ones memory as to my goals.
> a) Total cost less than $ 200
> b) 1 E-13 with a one second offset
> c) use parts attainable by every one
> d) easy to assemble only a few surface mount parts
> e) a five channel counter that yields 1 E 15 resolution and interfaces
> directly to a PC via RS232 or USB
> f) A counter that also gives you instant frequency difference at the
> sample rate, not only Allan Variance
> g) Modular so one can use only the Dual Mixer
> h) Modular so one can use multiple units to do simultaneous comparison
> of
> more than two oscillators.
> i) Isolation between D/M and counter so that the counter can be
powered
> by the PC USB port
>
> I am happy to report that all goals have been accomplished, attached is
a
> picture of the D/M, limitation of the file size does not allow me to
> attach
> an actual board picture, but if you contact me direct I will send you
> one,
> the final board is actually nicer since the first layout had to
> accommodate
> several variances.
>
> The D/M part leans heavy on the original NIST unit with a few
> substitutions
> and recommendations from Bob Camp. Also beside Opto Couplers SN65LVDS1's
> have been included for those that want to use other counting methods.
> Selection of filter capacitors allow the use at other offset
frequencies
> such as
> 10 and 100 Hz. The D/M fits in a standard 74 X 111 X 20 mm Euro case and
> the counter can be stacked below or next to it using the Opto Isolators
> as
> the inter connect. The SYPD-1's fit right on the board but connections
> are
> included to use the HP 10514 A. As a matter of fact removing the HP
mixer
> board from its housing fits it nicely on the board and every thing is
> still
> inside the housing.
> The counter will handle 1 an 10 Hz offset with a 1 E 14 resolution at 10
> Hz. Thanks to Richard Mc Corkle we have great drawings and code,
available
> to
> every one.
> Code, drawings, list of material and PC board layouts and its file, will
> be available to every one once the project is completed.
> I need help in the following areas
> a) help me create a nice set of drawings that are computer generated
> something I am not able to do
> b) create the computer program that takes the output of the counter board
> and allows Allan Variance plots, frequency difference and dual
temperature
> readings and plots using RS232 and USB.
> c) an independent test by a third party.
> As I said previously, I am not getting in the business of supplying parts
> but will work with people that will help achieve the three points listed
> above. Presently I have boards on order and will have two uncommitted
> board
> sets and probably also component kits.
> Please contact me directly.
> Again thank you Corby Dawson, Richard Mc Corkle and Bob Camp.
> Bert Kehren Miami
>
>
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