Jim,
Really annoying feature of HP counters.
If you slowly drift from a positive period to a negative one, it will indicate
negative numbers for a while.
Then almost sudden it will do the jump to 0.9 seconds.
I found that adding a phase delay (long cable) helps keep the numbers
Hi
Another simple solution -
If you are using a GPSDO as a PPS source, use the cable delay to offset the pps
you are using as a reference by a microsecond. That's worked on every GPSDO
I've tried it on.
No it really doesn't solve the problem, it just covers it up. Post processing
the data
Hi all,
given that digital scopes have a multichannel ADC for acquisition, which
is similar to what a cross-correlating phase noise measurement
instrument has, it occurred to me that phase noise measurement might
also be possible with a standard digital scope and some post-processing
Not only HP counters. I have never seen a TI counter that outputs
negative values. I use the cable delay or user delay feature of GPSes
to delay one PPS to the other so that the result is always positive. I
have seen that only oscilloscopes can handle negative time interval
values. Maybe that the
Hello,
given that digital scopes have a multichannel ADC for acquisition, which is
similar to what a cross-correlating phase noise measurement instrument has,
it occurred to me that phase noise measurement might also be possible with a
standard digital scope and some post-processing software.
Anybody have service, schematics or experience for one of these OCXO?
They are commonly seen in early HP 8566A spectrum analysers.
It is out of adjustable range.
Fortunately I had a spare OSC 49-61C floating about and replaced this off
frequency reference with it.
However the replacement tends
I would think that considering the amount of time it takes to get the data out
of the scope (particularly on the cheap scopes) would be a major impediment to
that method regardless of the cleanliness of whatever data you eventually get,
since you will only be able to analyze a small fraction of
Marek Peca wrote:
Hello,
given that digital scopes have a multichannel ADC for acquisition,
which is similar to what a cross-correlating phase noise measurement
instrument has, it occurred to me that phase noise measurement might
also be possible with a standard digital scope and some
Hi Mark,
I am not sure about the design of your OCXO but recently I repaired an
Ovenaire from a Cushman 5510 service monitor.
I found that there was a bad trimmer pot in the oven control circuit.
This wasn't apparent until I started monitoring the current drawn by the
unit while trying to
Hi Fred, Also, I neglected to ask, you wouldn't have the OXCO pin outs would
you?
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Frederick Bray
Sent: Thursday, 13 June 2013 2:01 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts]
(..)
I have tried it with a very cheap one, Rigol 2-channel, originally 50MHz,
reflashed to 100MHz. 2 signals, refmeasured, into Ch1, Ch2. Waveforms
(2x500Msps) acquired, sinc() interpolated. Results: short-term single-shot
jitter around 100ps RMS. Long-term was of no interest for my purpose
On Sun, Jun 9, 2013 at 11:29 PM, Bill Hawkins b...@iaxs.net wrote:
Hi, Thanks in advance.
Since this is a list for precise things, could you make your questions
more precise?
What sort of test cases?
What sort of calculations? Do you mean conversions?
What do you mean by catching
Marek Peca wrote:
(..) I have tried it with a very cheap one, Rigol 2-channel,
originally 50MHz, reflashed to 100MHz. 2 signals, refmeasured, into
Ch1, Ch2. Waveforms (2x500Msps) acquired, sinc() interpolated.
Results: short-term single-shot jitter around 100ps RMS. Long-term
was of no
My good old Spectracom 8170 is not setting time. I don't use it for
frequency, just as a clock for my Hazetorium. I live about 20
minutes north of downtown Los Angles in Glendale. The antenna I'm
using is the Ferrite Rod loop in PVC that came with the 8170. It's
located on my back porch
My point was, that DSO is basically an ADC. Therefore, there is some amount
of noise, nonlinearity and drift, limiting the jitter measurement. Do you
think any method can dig more information from given data than sinc()
interpolation and zero-crossing computation?
The cross-spectrum averaging
Burt
There is nothing wrong with your 8170. WWVB no longer allows it to work
correctly because of the phase modulation. They went to all psk about 1
month ago. They had been reverting back twice a day for things like the
8170.
So the ole 8170 is dead.
You need to build something like the d-psk-r
Burt
One other tidbit the phase mod will exactly cause what you see.
Spectracom used phase tracking to demodulate the AM time signal. Thats why
its nuts.
On Wed, Jun 12, 2013 at 5:49 PM, paul swed paulsw...@gmail.com wrote:
Burt
There is nothing wrong with your 8170. WWVB no longer allows it
Good catch by Russ of time-nuttery fame. Wrong ground on the 74hc390.
Updated schematic attached.
Thanks Rudd
Regards
Paul
WB8TSL
WWVB dpskr Costas_Div nu 12Mhz 06122013.sch
Description: Binary data
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To
12/31/1998 00:00:00 EST + 5184001 seconds = Time Date in UTC
01/01/1991 11:01 AM EST = XX/XX/ XX:XX UTC
Doug,
This is difficult (or impossible) to do right; at a minimum you need a table of
all past, current, and future national timezone definitions, DST rules by
locale, and leap
Hello to the list. I saw on K3PGP's site a mention that the UT-41 GPS receiver
had a 10KHz signal on-board so I decided, why not build a GPSDO for my new HP
5334B? Unfortunately the one I bought doesn't have a 10KHz point, and the
board doesn't even pull out the 1PPS signal from the chip. So
I think it depends on you definition of Unit Test. Some people do a
sanity check time test just to verify the function works. Those who want
a better test will use a code coverage tool and will add test cases untill
every path through the function is exercised.
One thing to remember is NO TEST
Paul,
U... What a revolting development this is. My 9150-52054 have a
smaller readout out that I can't see without climbing up on my bench,
so I suppose I will no longer know what time it is.
I've never really had to delve into the 8170 so I wasn't up to speed
on how they derived the
My dim memory says there is some analog way to multiply the phase noise.
What does that? Then it might be easier to measure.
On Wed, Jun 12, 2013 at 2:36 PM, Marek Peca ma...@duch.cz wrote:
My point was, that DSO is basically an ADC. Therefore, there is some
amount of noise, nonlinearity
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