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[time-freq] RefLock II configuration

John Ackermann N8UR jra at febo.com
Thu Mar 16 19:50:49 UTC 2006


Luis, thanks for this very helpful explanation.  It really helped clear 
things up for me.

73,
John
----

Luis Cupido wrote:
> MessageMichael,
> 
> f_conf sets the lock points, and lock points are multiples of the
> values in the table. As you know your frequency you should be abble to determine
> which submultiple fits better, just that.
> So the lock point is for you to decide if you want and can lock to that specific multiple.
> 
> (I agree that with such sintetic information as on the txt file it is not evident to configure
> nevertheless the minimum necessary is there. I'll can upgrade them with whatever
> makes it more easy to understand, if you have any sugestion just let me know).
> 
> Lets present a few examples with random values:
> 
> For 101.335 000 = xxx.xx5 000 (or xxx.xx0 000)
> one can lock at 5 or 2.5 or 1.25 or 1 KHz all will work
> 
> For 106.522 500 = xxx.xx2 500 (or xxx.xx7 500)
> only 2.5 and 1.25 KHz can be used.
> 
> For 106.522 000 = xxx.xxx 000 only 1KHz can be used
> 
> For 105.531 250 = xxx.xx1 250 (or xxx.xx3 750, or xxx.xx6 250, or xxx.xx8 750)
> only 1.25Khz can be used.
> 
> Note that to better understand the way it locks, imagine that the
> reflock only looks at the least significant digits of the frequency.
> When set to 5KHz lock point as far as the reflock is concerned,
> all of the frequencies 102.330 or 99.880 or 180.665 or 47.495 or 42.22 etc
> are equal it will lock them 5KHz digit downwards, other digits don't care.
> The same for all other lock points.
> 
> Since the lock capture range is the same as the lock point
> we should always use the highest value possible so to have the
> widest lock range (if the tuning range of the VCXO is very
> small this is irrelevant). (Phase noise wise 1KHz is the best).
> 
> 
> Hope this helps.
> 
> Luis Cupido,
> CT1DMK.
> 
> 
>   ----- Original Message ----- 
>   From: Owen, Michael 
>   To: TAPR time and frequency projects 
>   Sent: Thursday, March 16, 2006 6:42 PM
>   Subject: RE: [time-freq] RefLock II configuration
> 
> 
>   Dear Luis,
> 
>   I'm sorry, but when I examine r2_enhpps_30_1.txt, I don't see an explanation of how to determine the value for, say, f_conf.  Could you please explain how "-- f_conf=00 locks to 5KHz multiples (internal divider = 5000)"  is related to 1PPS -> 100 MHz?
> 
>   Thanks-
>   W9IP
> 
>     -----Original Message-----
>     From: time-freq-bounces at lists.tapr.org [mailto:time-freq-bounces at lists.tapr.org] On Behalf Of Luis Cupido
>     Sent: Thursday, March 16, 2006 11:25 AM
>     To: time-freq at lists.tapr.org
>     Subject: Re: [time-freq] RefLock II configuration
> 
> 
>     Hi Michael,
> 
>     The file "r2_enhpps_30_1.txt" on the configurations zip folder
>     has it all.
>     I agree it is in a "very compact style" but in fact should have it all.
>     Take a look, and if there are specific questions, let me know
>     (do it to the list please) I'll be glad to reply.
> 
>     Luis Cupido.
>     CT1DMK
> 
>     P.S. note that the N numbers on the PCB have different meaning for
>     each "pof" configuration file. Be sure to read the " *.pin " for the description
>     of where is what.
> 
>     The  " f_conf "  configures the lock point (that is the multiple of ).
>     for 100. 000 000 MHz use f_conf= 0,0
> 
> 
>       ----- Original Message ----- 
>       From: Owen, Michael 
>       To: time-freq at lists.tapr.org 
>       Sent: Thursday, March 16, 2006 2:54 PM
>       Subject: [time-freq] RefLock II configuration
> 
> 
>       I went out on a limb to convince my employer to try the RefLock II as a means of locking 1PPS to a 100 MHz OCXO.  Now we have received two kits and it's my responsibility to get them up and running.  In the absence of any written documentation, I need some help.  Although I have read through all the messages in the TAPR time-freq archive, I can't find anything that tells how to select the N divisor jumpers for 1PPS -> 100 MHz.  Also, I don't understand what the f_conf(0,1) jumpers are supposed to do.  Could someone please offer a suggestion? 
> 
>       73, W9IP
> 
> 
> 
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