-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Hal Murray
Sent: Thursday, October 25, 2012 12:45 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
li...@rtty.us said
li...@rtty.us said:
The gotcha with the DDS is phase truncation. That pretty much trashes the
ADEV.
Thanks.
How should I think about the output of a DDS?
Lets assume I'm interested in the frequency domain where the error is
measured in phase noise. For a DDS, I think they are spurs.
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, October 22, 2012 3:45 PM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Tom said:
In general, when you discipline a OCXO you get that characteristic ADEV
hump.
At some point there is a cross-over
On 10/23/2012 11:16 PM, Tom Van Baak wrote:
Warren,
Awesome plot. I've seen ADEV humps move left and right depending on tuning, but
that Excel plot makes it very clear. Thanks for sharing it. Can you send the
XLS file so we can play with it some more?
I agree with Tom, please share the
measurement
Sent: Sunday, October 21, 2012 8:49 PM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Dear Tom,
Good evening. In relation to your last comments on this and other subjects,
I am sharing some thoughts and experience about it. I took the liberty to
separate the topics
of the hump; medium is the hump, and long is tau to the right of the
hump.
/tvb
- Original Message -
From: ewkeh...@aol.com
To: time-nuts@febo.com
Sent: Monday, October 22, 2012 4:04 AM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Tom
I have two questions what should the range
, I guess in this case
short is tau left of the hump; medium is the hump, and long is tau to the
right of the hump.
/tvb
- Original Message -
From: ewkeh...@aol.com
To: time-nuts@febo.com
Sent: Monday, October 22, 2012 4:04 AM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
- Original Message -
From: ewkeh...@aol.com
To: time-nuts@febo.com
Sent: Monday, October 22, 2012 4:04 AM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Tom
I have two questions what should the range, resolution and stability of
the delay generator be and how much do you
...@aol.com
To: time-nuts@febo.com
Sent: Monday, October 22, 2012 4:04 AM
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Tom
I have two questions what should the range, resolution and stability of
the delay generator be and how much do you think a digital loop driven by a
Tbolt
-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Monday, October 22, 2012 7:05 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
Tom
I have two questions what should the range, resolution and stability of
the delay generator be and how much do you think
There's a history to many of the GPSDO products you hear us talk about.
I believe the original TBolt (fancy red case) did have an OCXO but it wasn't
particularly high quality. Perhaps Bob can shed light on this.
99% of TBolt's found on the surplus market today, and all the ones in the TAPR
-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak
Sent: Monday, October 22, 2012 1:00 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
There's a history to many of the GPSDO products you
On 22 Oct, 2012, at 12:48 , Bob Camp li...@rtty.us wrote:
The big bucks approach probably is to run a good RF ADC on the input and
then do all the offset stuff as DSP math. The VCXO just sits at it's magic
frequency and never moves. More money / no pops.
A somewhat cheaper way might be to
measurement
Subject: Re: [time-nuts] Adjusting HP 5065A frequency
On 22 Oct, 2012, at 12:48 , Bob Camp li...@rtty.us wrote:
The big bucks approach probably is to run a good RF ADC on the input and
then do all the offset stuff as DSP math. The VCXO just sits at it's magic
frequency and never
On Mon, Oct 22, 2012 at 1:00 PM, Tom Van Baak t...@leapsecond.com wrote:
There's a history to many of the GPSDO products you hear us talk about.
I believe the original TBolt (fancy red case) did have an OCXO but it
wasn't particularly high quality. Perhaps Bob can shed light on this.
99% of
Bert,
On 10/22/2012 04:46 PM, ewkeh...@aol.com wrote:
Tom
A good place to start is with a manual of the Austron 2055 delay if there
is real interest. Does any one have it in PDF form?
As to the disciplining a Rb or specifically a HP5065A, the filter part is
the challenge. Having worked on it
On 10/22/2012 07:53 PM, Bob Camp wrote:
Hi
The gotcha with the DDS is phase truncation. That pretty much trashes the
ADEV.
True, but the more bits you apply the better performance you get.
Modern DDS clock chips do have pretty amazing specs for the money you spend.
Cheers,
Magnus
Magnus
Are you changing or did you change and if you are how much time do you
have.
Bert
In a message dated 10/22/2012 6:24:06 P.M. Eastern Daylight Time,
mag...@rubidium.dyndns.org writes:
Bert,
On 10/22/2012 04:46 PM, ewkeh...@aol.com wrote:
Tom
A good place to start is with a
Hi
Modern parts are pretty cool. I have measured them them for this application.
The truncation still is a big issue.
Bob
On Oct 22, 2012, at 6:16 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 10/22/2012 07:53 PM, Bob Camp wrote:
Hi
The gotcha with the DDS is phase
Warren,
On 10/23/2012 12:45 AM, WarrenS wrote:
Tom said:
In general, when you discipline a OCXO you get that characteristic ADEV
hump.
At some point there is a cross-over and you know/assume that at that
point
each must be contributing 1/sqrt(2) of the noise.
Although putting the Hump at
On 10/23/2012 12:41 AM, Bob Camp wrote:
Hi
Modern parts are pretty cool. I have measured them them for this application.
The truncation still is a big issue.
If you generate a lower frequency and gear it up in frequency, you would
get better result. It's more or less what the phase
Hi
Yes, a DDS at high freq./ narrow band crystal filter / divide to low audio /
image reject mix with input back to rf / lock to VCXO approach would get around
much (but not quite all) of the truncation stuff. It's complex enough that I
suspect that ADC approach would give it a run for the
Dear Corby,
Good morning. Thank you for the detailed instructions to bring the 5065A close
to desired frequency. I couldn't have a cleaner explanation of the process.
Yesterday evening I tried adjusting the C field in small steps using a mixer,
lpf and two oscillators setup as my current
Hi Edgardo --
One slightly frustrating thing about the 5065A is that its frequency
settability isn't as good as its short term stability. I believe the manual
says that the small divisions on the C-field counter dial are 2x10e12, and it's
hard to set closer than that.
A good 5065A is a
Dear John,
Thank you for your kind comments. May I assume that a temperature controlled
environment for the 5065A is one similar to a data center with A/C? Or a room
without A/C but keeping a minimum temperature variation? Perhaps +/- 5ยบ C/F?
My small lab shares the space with my ham shack. No
John
I agree with your observations. Before my time nuts time I did make the
mistake of getting rid of my 5065A since I did have a Shera disciplined FRK
and had gotten hold of quite a few HP5061A's and FTS 4000's. Big mistake.
Gave no attention to A/V. Phase noise yes but I went about it by
Anybody in the middle of the country (Kansas City) have a maser or 5065a? I
want to test my super-charged gpsdo but don't have the tools.
Doc
KX0O
Sent from my iPad
On Oct 21, 2012, at 11:43 AM, ewkeh...@aol.com wrote:
John
I agree with your observations. Before my time nuts time I did
Anybody in the middle of the country (Kansas City) have a maser or 5065a? I
want to test my super-charged gpsdo but don't have the tools.
Doc
KX0O
If not, for the cost of shipping, you're welcome to send it here for comparison
against my masers. Contact me off-list for details.
/tvb
Hi Edgardo,
What you'll find is that many labs do not periodically adjust the C-field of
their 5061A or 5065A at all.
Instead, any phase or frequency adjustment is done with phase microsteppers or
simply done in software with time and rate adjustments to the raw data. These
methods avoid all
Dear Tom,
Good evening. In relation to your last comments on this and other subjects, I
am sharing some thoughts and experience about it. I took the liberty to
separate the topics as to ease the interested parties to follow up accordingly.
TNX.
a. Information you kindly provided and the
to
additive noise, but it will guarantee the best possible long-term accuracy.
/tvb
- Original Message -
From: Edgardo Molina
To: Tom Van Baak ; Discussion of precise time and frequency measurement
Sent: Sunday, October 21, 2012 8:49 PM
Subject: Re: [time-nuts] Adjusting HP
I did this on a lark one day. 5065A - doubler block - tbolt Seemed to work
very well, but I didn't do any serious testing of it.
---
There's a third alternative as well. You might consider using your 5065A as the
LO in a GPSDO. This will sacrifice some short- and mid-term
Dear Tom and Mark,
Interesting suggestion Tom. Thank you. I will seriously consider it and for the
time being, put in on my wish list until I gather more specific information to
achieve it. Have you done it before? That could pave the road to success.
Mark. Do you have more specific
Edgardo,
You do use the C-field adjust to put a 5065A On frequency. The Factory
values are a moot point after all these years!
Just incrementaly adjust the c-field control in small steps while
observing the frequency comparison.
The only thing that might happen is that you reach one end of the
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