This was exactly the case on my Rb. It was suggested by the OEM that one
could directly connect the 0/5V serial connection to a PC RS232 serial
port (but with the warning that reversing the TX/RX connection could
destroy it). So the polarity was inverse from what you'd normally expect
on a 0/5V
For a project at work, I'm looking for a good close in phase noise
oscillator (better than -100dBc@ 10Hz, -120dBc would be nice) at 100 MHz
in a SMT form factor. But it doesn't need good temperature stability.
There's tons of SMT OCXOs out there with reasonably good performance,
but they draw
On 2015-08-26 01:47, Anders Wallin wrote:
Hi all,
Is there a ready made set of scripts for monitoring a bunch of NTP servers?
Preferably for generic unix/linux like ubuntu.
I imagine it would look something like:
1. measure data with a test machine, either use output of ntpq -p or
perhaps
anders.e.e.wal...@gmail.com said:
Is there a ready made set of scripts for monitoring a bunch of NTP servers?
Preferably for generic unix/linux like ubuntu.
ntpd includes optional logging facilities to collect most of the raw data you
might want to analyze.
Details are in monopt.html If
It would be interesting to hear what (if any?) real-time kernels are used on
NTP servers and if that is one way to measure/generate 1PPS input/output.
There are 2 ways to process PPS timing.
The traditional way is for a change on a modem control signal on a serial
port to generate an
Hi,
On 08/26/2015 06:28 AM, Brian M wrote:
Hi -
So I took the time tonight to poke at things with the scope. Hopefully it
will be of interest.
First off, I probed the MCU (MC68HC11) TX line directly. And, it looks like
I misstated in my last mail. The MCU itself is 5V TX idle TTL Serial. On
Dan Drown has also done some interesting work with PPS latency measurements
on BBB (it's been posted to time-nuts before). He essentially measured the
difference between the PPS input capture count and the count at which the
ISR was serviced in a kernel module. His experiments suggest somewhere
On 8/26/15 1:28 PM, steve heidmann via time-nuts wrote:
Rakon has always impressed me .
I'll take a look. The online datasheets don't have phase noise data for
close in frequencies (at least the 3 I looked at).. some give a
integrated jitter but it's for 12kHz and out, and I've noticed
Am 26.08.2015 um 22:04 schrieb Javier Herrero:
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
looks just like this one from Crystek:
http://www.digikey.de/product-search/de?keywords=cvhd-950
but that
Hi
Further investigation by list members in China came back with the information
that this particular
design is indeed a FLL. The error is considered “acceptable” by the designer.
This is not the case
on the various CDMA oriented GPSDO’s we typically play with in the US and
Europe. All of
Full KE5FX evaluation of BG7TBL GPSDO here: http://www.ke5fx.com/gpscomp.htm
I'm wondering out loud if it might, like many hobbyist GPSDO's, be
frequency-locked rather than phase-locked and thus susceptible to
last-digit-counter bobble in some long-averaging counter.
Tim N3QE
On Wed, Aug 26,
Hi all,
Is there a ready made set of scripts for monitoring a bunch of NTP servers?
Preferably for generic unix/linux like ubuntu.
I imagine it would look something like:
1. measure data with a test machine, either use output of ntpq -p or
perhaps python and ntplib. Variable measurement
I have some pieces and parts inside of a Zabbix instance that do some
home-class NTP monitoring.
No alerts configured, but I wouldn't anticipate those being difficult to add..
I can forward (or send to the list) templates if anyone is interested.
David
On Wed, Aug 26, 2015 at 9:53 AM, David
Hello,
Thank you for the answers.
I've already posted my formulas that work for phase noise.
But John, I will now try your method with the Timepod and see how they
compare.
I did get the N corner to work with the Timepod, but as you say, that's for
ADEV.
Just a personal note. The
Hello,
I asked for a 3 corner hat measurement for phase noise.
Managed to work it out myself.
In case anyone else wants to know:
First of all Timepod does do it but only for Allan Deviation.
But I wanted it for phase noise.
So if you make three phase noise measurements A vs B (call result
Back in 2012 while playing with LinuxCNC, a program for real-time control
of CNC machines, I made a few graphs on the real-time vs. normal kernel
performance:
http://www.anderswallin.net/?s=latency
These are purely software generated and measured events (i.e. we set a
thread to run at 1 ms
Hi all,
Is there a ready made set of scripts for monitoring a bunch of NTP servers?
Preferably for generic unix/linux like ubuntu.
I imagine it would look something like:
1. measure data with a test machine, either use output of ntpq -p or
perhaps python and ntplib. Variable measurement interval,
Hello,
Re my measurements with the timepod.
John Miles has now saved me a ton of work by telling me how to using three
sources in the timepod, to automatically get the absolute phase noise of a
device (without having to result to 3 corner formulae).
John, I have one more question. What about
Example monitoring graphs and criteria might be those done by pool.ntp.org:
http://www.pool.ntp.org/scores/71.191.185.32
I believe they send out E-mails to server owners based on criteria.
I don't personally agree with all of the details of their criteria, it
seems to be oriented more towards
Hi,
On the EEVBLOG (http://www.eevblog.com/forum/index.php)
They mention that the 2014-11-06version GPSDO that was “most extensively
tested, so far (by ke5x and others).
(Has a) known bug, outputfrequency is not exactly 10mhz (9,999,999.999,800 Hz).
This translates to ~2hzerror at
Hello, Jim,
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
They say that they are 3rd overtone, but it seems more an AT-cut than a
SC, and anyway is around 10dB poorer than your requirements. An I
Rakon has always impressed me .
From: Jim Lux jim...@earthlink.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wednesday, August 26, 2015 11:23 AM
Subject: [time-nuts] looking for SMT oscillator SC cut, with no oven
For a project at work, I'm
On 8/26/15 2:38 PM, Gerhard Hoffmann wrote:
Am 26.08.2015 um 22:04 schrieb Javier Herrero:
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
looks just like this one from Crystek:
But if he needs 100dBc at 10Hz that is Wenzel's stronghold
[https://twitter.com/ultralownoise]
look that: http://www.wenzel.com/wp-content/parts/501-04517.pdf
73
KJ6UHN
Alex
On 8/26/2015 2:38 PM, Gerhard Hoffmann wrote:
Am 26.08.2015 um 22:04 schrieb Javier Herrero:
I suppose that one of
dk...@arcor.de said:
SC requires high temperature, that does not go together well with SMD and
low power.
Is there anything fundamental about SC that forces the turn over temperature
to be high?
Or is is something like SC is only used in ovens and they have to be higher
than ambient so
On 8/26/15 1:04 PM, Javier Herrero wrote:
Hello, Jim,
I suppose that one of the alternatives that you've explored are the
ABLNO from Abracon http://www.abracon.com/Precisiontiming/ABLNO.pdf
They say that they are 3rd overtone, but it seems more an AT-cut than a
SC, and anyway is around 10dB
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