El 28/01/2012 00:17, claudio.gira...@virgilio.it escribió:
Hello John,
thanks for maintaining the 5680A FAQ;
regarding its
frequency resolution, have you checked the DDS FSELECT pin (and maybe
also PSEL0/1) to see if they are doing some kind of dithering of the
DDS frequency ?
I've just checked
El 27/01/2012 19:27, beale escribió:
I added a bit to the electronics section of the FE-5680A FAQ as below.
http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq#electronic
(Note- until today, I had the 8 and 6 digits transposed, calling it the
fe5860a. But no one noticed
And I think it depends on the two frequencies loaded too. The FSELECT
selects between two phase accumulator steps. Maybe the word sent to the Rb
is manipulated to obtain two symmetric values to load.
On Sat, Jan 28, 2012 at 3:21 PM, Javier Herrero jherr...@hvsistemas.eswrote:
El 27/01/2012
Symantec just doesn't like .EXE files from unknown sources. You could try
Zipping it first
Rob Kimberley.
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of J. L. Trantham
Sent: 28 January 2012 01:48
To: 'Discussion of precise time and
The star catalog specifically designed for lunar occultations is the XZ (I'm
guessing it stands for eXtended Zodiacal) Catalog from the US Naval
Observatory. It's based on the earlier ZC and covers the band of brighter stars
that can be occulted by the moon. Simbad should have these catalogs.
LH TB experts,
I have three Thunderbolts bought over several years. My older unit Mfg:
29-Sept-2000 has f/w 2.12 and besides working flawlessly providing 10Mhz and
PPS references, one annoying issue is that this unit has three LH (ver. 3.00
beta) display fields that are obviously not
All,
Thank you all for the information on what to look for with
FE-5680A's and related standards. I've been watching eBay the past few
days and I think I'll be able to get two or three in the next couple
days. I saw a set of ten for $349.00 which looked like a good deal...
But I decided
It can be... but the resolution of the center frequency of two DDS
frequencies would be limited to half DDS LSB... so not enough. I will
try to monitor FSELECT and also to extract some SPI data if I found some
free time today or tomorrow :)
Regards,
Javier, EA1CRB
El 28/01/2012 15:35,
The January 28th Science News has an editorial by Tom Siegfried that
points out that neutrinos were predicted to conserve the energy in
radioactive beta decay. The OPERA results show unbalanced energy
in the other direction. The pions that decay and create neutrinos
do not have enough energy to
Only to note that I measured at the wrong place... the reference
frequency to the DDS is 20MHz, not 10MHz as I stated :)
Regards,
Javier, EA1CRB
El 28/01/2012 15:21, Javier Herrero escribió:
El 27/01/2012 19:27, beale escribió:
I added a bit to the electronics section of the FE-5680A FAQ
The lower bits can be pulse width modulated to get finer resolution,
but it gets harder to maintain monotonicity. Eventually you run out
of processing resolution, or the control signal falls into the noise
floor, whether the system is digital, analog, or both.
Ed
Javier Herrero wrote:
Sat
I've checked now that they do not seem to be any activity on the DDS SPI
lines during normal operation. I've tried with several small offsets
through the serial port, and the square wave at FSELECT seems to be same
square, no appreciable duty cycle variation.
Regards,
Javier
El 28/01/2012
Another though... The FE5680A manual says that the most basic unit
outputs 50.255+ MHz (1/136 the Rb oscillation frequency). I suppose that
this is the other style of units, that uses a 50.255MHz crystal to
excite the cavity. 50.255MHz/2^48 is 1.785416^-7Hz, the claimed
resolution for these
All,
I am getting ready to order a few FE-5680A's from eBay and I noticed
that all of the sellers are from Asia. Is this typically the case or
are there some US based sellers? The reason I ask is because I'm always
leery of buying things that ship from Asia. I've ordered stuff twice
from
That's the beauty of e-Pay ... you pays your money and you takes your chances.
However, I was only stung once by a far east seller and since I used PayPal, I
got a full refund. Only cost to me was wasted time.
73, Dick, W1KSZ
-Original Message-
From: Brad Stockdale b...@shinji.net
My experience, and it seems that of others on this group, has been good.
Peter
On Jan 28, 2012, at 5:28 PM, Brad Stockdale b...@shinji.net wrote:
All,
I am getting ready to order a few FE-5680A's from eBay and I noticed
that all of the sellers are from Asia. Is this typically the case
Surely the proximity of the Moon to the surface of the Earth
makes the timing of an occultation dependent on where you are on the
Earth's surface. (Parallax error)
The calculations to correct for this must make it a mathematicians
picnic.
Nevil Maskelyne, tormentor of John Harrison, advocated
Has anyone seen a sevice manual or a schematic for the HP-5328A Option
21 DVM. I have the 5328A service manual but it says the DVM Option 21
is covered in a separate manual. Without a schematic debugging could
take a long time as the DVM is spread over three plug-in boards.
Thanks,
Chris
Chris:
The theory of operation, along with the usual block diagrams, schematics, etc,
for the OPT 021 for the 5328B is in the 5328B service manual. It may be the
same, or at least close enough to, the 5328A. It's worth a try. You can
download the 5328B manual here:
Tom,
Thanks. Turns out the unit I have looks just like a 5328B. Even if
it says A. The photos match the cards.That is once complex volt
meter but will be worth it if I can get it working HP claims 0.03%
accuracy and a uV to KV range.
Chris
On Sat, Jan 28, 2012 at 8:26 PM, Tom Curlee
Hi guys
I'm planning to build a GPSDO to use as a frequency ref for my GHz ventures.
I've done research in what other people have built - but I have no
experience working with long-term precision/stability products (nor do I
have the equipment to do so -- I think).
I'm using the Jupiter T (the
Hi Ray,
please find on this link the info what you are looking for.
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
Rgds Ernie.
-Original Message-
From: Ray Xu rayxu...@gmail.com
To: time-nuts time-nuts@febo.com
Sent: Sun, Jan 29, 2012 7:51 am
Subject:
Ray:
I used a similar circuit to lock my 10 GHz LO to GPS. I used a similar Jupiter
GPS board receiver (not the 'T' version). My 10 GHz LO is one of the older
Microwave Associates brick type of oscillators. It has an internal 106.5
crystal oscillator that is in a crude oven. The 106.5 is
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