[time-nuts] Dual Mixer

EWKehren at aol.com EWKehren at aol.com
Tue May 11 15:07:38 UTC 2010

Thank you Karesz.
I will contact you direct and we can look at what needs to be done. Nothing 
 Fancy.   Bert
In a message dated 5/11/2010 10:59:17 A.M. Eastern Daylight Time,  
szeker.k at gmail.com writes:

Hi  Bert,

I can help you in PCAD schema drowing(i.e. as xxx.pdf output  too)_have a
litle experiance :-).
(so ca. 20 years, & with RF  layouting so good 30 years)...

Best  Greetings,

2010/5/11 <EWKehren at aol.com>

> 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 
>  more than two oscillators.
> i)   Isolation between D/M and  counter so that the counter can be  
> 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 
> an  actual board picture, but if  you contact me direct I will send you 
> 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 
>  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 
> the inter connect. The  SYPD-1's fit  right on the board but connections 
> included to use the HP  10514  A. As a matter of fact removing the HP 
> 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, 
> 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 
> 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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