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[time-freq] RefLock II behavior

Luis Cupido cupido at mail.ua.pt
Wed Jun 21 15:06:48 UTC 2006


Michael,

With +-4Hz range, the +/-0.5Hz  it is clearly not a dac dithering issue.
It is a gps-1pps issue for sure.

Luis Cupido
CT1DMK.

P.S. Basic question, is the input level ok ?
is the CPLD receiving a clean sq wave ?
Are you sure of the 1pps polarity ?

----- Original Message ----- 
From: "Owen, Michael" <Michael.Owen at Sensis.com>
To: "TAPR time and frequency projects" <time-freq at lists.tapr.org>
Sent: Wednesday, June 21, 2006 1:33 PM
Subject: RE: [time-freq] RefLock II behavior


All -

Thanks for the input.  My (well, my employer's) setup is this: 

Fei-Zyfer GSync GPS RX w/1PPS output
(http://www.fei-zyfer.com/gsync.html)
RefLock II
  f_conf   = 00
  avg_conf = 00
  pps_pol  = 0
  ld_conf  = 5 (R5=0,R4=0,R3=0,R2=1,R1=0,R0=1)
OCXO is Wenzel Assoc 501-14217
(http://www.wenzel.com/datasheets/Onyx/501-14217.htm) Tuning range is
+/-4Hz 0-10 VDC
Freq counter is Agilent 53131A-02
(http://cp.literature.agilent.com/litweb/pdf/5967-6039EN.pdf) calibrated
last month.

I have changed R22 to 68K as per Peter G2XO(?) via Steve Bible because
the "stock" VTUNE range was insufficient.

Ideas are welcome!

73,
W9IP

------
Michael R. Owen, Ph.D.
Senior System Engineer
Sensis Corporation
(315) 634-3066 



|-----Original Message-----
|From: time-freq-bounces at lists.tapr.org 
|[mailto:time-freq-bounces at lists.tapr.org] On Behalf Of Robert McGwier
|Sent: Tuesday, June 20, 2006 9:48 PM
|To: TAPR time and frequency projects
|Subject: Re: [time-freq] RefLock II behavior
|
|
|Mike:
|
|Could you provide a little more description of your set up?  What is 
|your reference,  what is the tuning range on your VCO in frequency and 
|voltage?
|
| I can lock my oscillators using 1pps GPS or 10 MHz rubidium sing 
|modified Reflock I and it will NEVER be that far off.  What 
|you are see 
|is 0.15 ppm.  That is really messed up.   You should be seeing 
|one part 
|in 10^10 at least from GPS (say).  My PTS-160 synthesizer 
|locked to this 
|source is extremely stable.
|
|
|Bob
|
|
|
|
|
|
|Owen, Michael wrote:
|>
|> Dear friends,
|>
|> Thanks to Steve Bible, I got my brain un-stuck and figured out how to
|> set the 0-ohm jumpers (I'll summarize everything in a couple of days 
|> when it's all finished and my shame has faded).
|>
|> For right now, I have a question.  RefLock plus my pretty good OCXO
|> are trying to settle at 100 MHz but there are sharp spikes every few 
|> minutes.  Here's an image:
|>
|>
|-pix-snip-
|>
|> The time span is about 40 minutes.  Even after 3+ hours, the spikes
|> are still there (although more rarely).  Does anyone have an 
|idea how 
|> to get rid of them?
|>
|> 73, W9IP
|>
|> ------
|> Michael R. Owen, Ph.D.
|> Senior System Engineer
|> Sensis Corporation
|> (315) 634-3066
|>
|> 
|----------------------------------------------------------------------
|> --
|>
|> _______________________________________________
|> time-freq mailing list
|> time-freq at lists.tapr.org 
|> https://lists.tapr.org/cgi-bin/mailman/listinfo/time-freq
|>   
|
|
|-- 
|AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, 
|NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman 
|Laziness is the number one inspiration for ingenuity.  Guilty 
|as charged!
|
|
|_______________________________________________
|time-freq mailing list
|time-freq at lists.tapr.org 
|https://lists.tapr.org/cgi-|bin/mailman/listinfo/time-freq
|

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