date:20120105

On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
hmur...@megapathdsl.net wrote:

albertson.ch...@gmail.com said:

 Have an older Tek 465 scope that is in only fair shape and I see nothing
 on that pin but milivolt level sine wave of about 60MHz.  I can't set the
 scope to show any hint of a PPS ...

I do have a 465.  You should be able to see a 1 uSec PPS.

60MHz is about a 6nS rise time and is easily fast enough to see it.

Now turn up the Intensity until you can see the pulse.  It might help to turn 
down the room lights.

This is the problem.  With a 1 second repetition rate, the brightness
is going to be very low.

The old ways of viewing such a low repetition rate signal include
using a hood or dark room, special CRT phosphors, photographic film,
MCP (micro channel plate) intensified CRTs, and of course analog
storage and later digital storage.

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Re: [time-nuts] FE-5680A performance -- 5125

2012-01-05 Thread Bob Camp

Hi

I have seen a 5125 do random reboots on a every few weeks basis. I suspect
it's either a problem box or we have a power glitch that it's uniquely
sensitive to.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of John Miles
Sent: Thursday, January 05, 2012 10:35 AM
To: 'John Ackermann N8UR'; 'Discussion of precise time and frequency
measurement'
Subject: Re: [time-nuts] FE-5680A performance

 To get around this, you can use the TSC's frequency counter output which
 gives 14 or 15 digit measurements.  However, you need software to
 manually poll for the fcounter data, and you can't get precise tau from
 it since the updates don't seem to happen synchronously.  I ended up
 writing a perl script that grabs and logs the fcounter data every 10
 seconds by default, and that has worked well.

My guess is that their phase-difference output is a filtered version of the
full-bandwidth phase data generated for the PN display, as opposed to being
generated by running the raw I/Q data through a separate filter path and
doing the atan() operations at the final ENBW.   These strategies yield
similar but not quite identical results.  Any frequency calculations based
on sending the full-bandwidth phase data through the ENBW filter will be
off-kilter.  

It's true that their frequency counter display seems to be correct in all
cases, though -- if I'm right about the problem with the phase/freq
difference displays, they must be using a separate, correct filter path to
drive the frequency count chart.
 
Since TimeLab's frequency chart relies solely on the phase data stream, it
is vulnerable to the same error that you're talking about.  I don't attempt
to correct the data by reading the frequency counter or anything like that,
so yes, that's something to watch out for.  It caused me some
head-scratching.

Fortunately the error doesn't seem to be severe enough to distort the
phase-difference trace visibly, or to affect the ADEV and other plots.  It's
only an issue if you need accurate frequency readings.

 John, could you expand on your comment about the ethernet connection?  I
 have seen random instances where the TSC seems to lose its TCP/IP
 settings, but so far it's never happened during a measurement run, so
 has been annoying but manageable.

When I first wrote the code for Tom's 5120A, I noticed that the TCP
connection would sometimes get really sluggish, and occasionally be dropped
altogether.   Later TSC firmware allowed the data rate to be slowed down to
1, 10, or 100 readings per second instead of 1000, and I imagine that fixes
the problem entirely.  However, the TimeLab driver is still hardwired to
assume the data is coming in at 1000 samples/second.  

-- john
Miles Design LLC




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Re: [time-nuts] Thunderbolt? (re simple gpsdo.)

2012-01-05 Thread Attila Kinali

On Fri, 30 Dec 2011 22:54:26 -0800
Chris Albertson albertson.ch...@gmail.com wrote:

 I don't count anything with a computer and software inside as
 simple.   My definition of a simple device is a capacitor or a
 transistor or I guess a single flip-flop or op-amp.   A simple
 controller would some how use about two dozen or less of these kinds
 of components.

I think, then the simplest solution is to use a LEA6-T, programm
the second timing output to 8MHz (not 10!), and use a PLL and you
get a GPSDO like the one James Millerd designed a few years ago, based
on the Jupiter GPS.

Here, the only time you need a computer is when you configure the LEA6-T,
which can be done using USB or a serial port and the config can be stored
in the EEPROM of the LEA.

AFAIK the bigest catch here would be the update rate of the timing
solution of the LEA and the introduced phase glitches. From what i
know, the LEA provdies two modi for the freqency output, one is
phase locked to the 1PPS, and the other is frequency locked.
This together with the low update times, will require long integration
constants for the PLL loop, which might make the thing problematic.


Attila Kinal

-- 
Why does it take years to find the answers to
the questions one should have asked long ago?

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

2012-01-05 Thread beale

I think there is something funny about the 1 PPS output on pin 6 from the 
currently available cheap FE-5680A units. I have three of these units. On one 
unit, on one occasion, I did observe a logic-level 1 PPS pulse, exactly 1 
microsecond wide.  But after a power cycle it never came back, although the 
unit indicates a locked condition, and is apparently working. The other two 
units also seem to work (10 MHz output OK, lock OK) but I have never seen a 1 
PPS signal on pin 6 from them. My Tek TDS-210 is easily capable of triggering 
on and displaying a 1 usec pulse.  Is it possible the pulse appears only after 
a RS-232 command, or after some other special condition?


  ---Original Message---
  From: David davidwh...@gmail.com
  To: Discussion of precise time and frequency measurement time-nuts@febo.com
  Subject: Re: [time-nuts] FE-5680A performance
  Sent: 05 Jan '12 07:49
  
  On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
  hmur...@megapathdsl.net wrote:
  
  albertson.ch...@gmail.com said:
  
   Have an older Tek 465 scope that is in only fair shape and I see nothing
   on that pin but milivolt level sine wave of about 60MHz.  I can't set the
   scope to show any hint of a PPS ...
  
  I do have a 465.  You should be able to see a 1 uSec PPS.
  
  60MHz is about a 6nS rise time and is easily fast enough to see it.
  
  Now turn up the Intensity until you can see the pulse.  It might help to 
 turn
  down the room lights.
  
  This is the problem.  With a 1 second repetition rate, the brightness
  is going to be very low.
  
  The old ways of viewing such a low repetition rate signal include
  using a hood or dark room, special CRT phosphors, photographic film,
  MCP (micro channel plate) intensified CRTs, and of course analog
  storage and later digital storage.
  
  ___
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Re: [time-nuts] FE-5680A performance




On 05/01/2012 16:49, David wrote:

On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
hmur...@megapathdsl.net  wrote:


albertson.ch...@gmail.com said:

Have an older Tek 465 scope that is in only fair shape and I see nothing
on that pin but milivolt level sine wave of about 60MHz.  I can't set the
scope to show any hint of a PPS ...

I do have a 465.  You should be able to see a 1 uSec PPS.

60MHz is about a 6nS rise time and is easily fast enough to see it.


Now turn up the Intensity until you can see the pulse.  It might help to turn
down the room lights.

This is the problem.  With a 1 second repetition rate, the brightness
is going to be very low.

The old ways of viewing such a low repetition rate signal include
using a hood or dark room, special CRT phosphors, photographic film,
MCP (micro channel plate) intensified CRTs, and of course analog
storage and later digital storage.

I agree, I've seen it in a Tek 7623A with the storage on, it is quite 
difficult without it.


Regards,
Ignacio, EB4APL

PD. Just trying to verify this I made some error and let the magic smoke 
leave the unit. It is still smelling ...



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[time-nuts] Navsync CW12 - More Info

2012-01-05 Thread Ed Palmer

Okay, I've cooled off - a bit.  The bottom line is that the 10 MHz 
output of the CW12 isn't appropriate for what I wanted to do.  Ah, the 
joys of reading and understanding a spec sheet!


But let's not throw out the baby with the bathwater.  Although the 10 
MHz output has it's issues for typical Time-Nut applications, the 1 PPS 
output is great.  Here are some measurements that I've made over the 
past few years on a few GPS receivers and a couple of GPSDOs.  I measure 
1000 periods of the 1 PPS and look at the results.  Every run gives 
somewhat different results so I've shown some typical ranges.  These 
measurements were made with an HP 5372A.  YMMV.


Device .. Std Dev (ns) Range (max-min)(ns) ... Device Type

Navsync CW12  4 - 5 .. 20 - 25 ... GPS Rcvr
Motorola UT+  40 - 55  95 - 110 .. GPS Rcvr 
* see below

Rockwell Jupiter  10   50 ...  GPS Rcvr **
Motorola M12M ... 10 - 15  40 - 60 ... GPS Rcvr

Trimble Thunderbolt . 0.4 - 0.5 .. 2 - 4 . GPSDO
HP Z3801A ... 0.3  2 . GPSDO***


*   Most of my UT+ 'range' results were in this group, but there were a 
few at 20 - 30.

**  Only one result.
*** Only one result.  I need to do more testing on the Z3801A


As you can see, the Navsync CW12 is by far the best of the GPS 
Receivers, but nowhere near as good as the GPSDOs.  However, imagine 
using the CW12 to discipline a good OCXO to build your own GPSDO.  Or 
using it to discipline a PRS10 Rubidium or X72 Rubidium oscillator.  You 
can't do it with the 10 MHz output, but the 1 PPS output is another story.


Ed




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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

On Thu, Jan 5, 2012 at 9:46 AM, beale be...@bealecorner.com wrote:

 I think there is something funny about the 1 PPS output on pin 6 from the
 currently available cheap FE-5680A units. I have three of these units. On
 one unit, on one occasion, I did observe a logic-level 1 PPS pulse, exactly
 1 microsecond wide.  But after a power cycle it never came back, although
 the unit indicates a locked condition, and is apparently working. The other
 two units also seem to work (10 MHz output OK, lock OK) but I have never
 seen a 1 PPS signal on pin 6 from them. My Tek TDS-210 is easily capable of
 triggering on and displaying a 1 usec pulse.  Is it possible the pulse
 appears only after a RS-232 command, or after some other special condition?


I think the signal is there, it is just very small

I tried again this morning.  On mine the pulse is there but it's very weak.
  I can't see it one the scope but I can see the trigger light flash every
second if I work to set it just right.  I also see an about 0.3V peak to
peak, about 60MHz sine wave.   I can get the scope to trigger and display
the sine wave just fine.  I have to use a 10X scope probe or I load the
signal to millivolts

The PPS signal coming from my Oncore GPS is easy to see on my scope and
even on a DMM set to DC Volts

The FE-5680's PPS is not usable directly with my counter, I have to amplify
it then set the counter to 10X attenuation then mess with the trigger
setting so it does not see the 60MHz signal. Maybe I'm lucky that my
scope has a BNC output on the back for the vertical amplifier, so I can
apply a 20MHz low pass filter and about 20X voltage gain.

The documentation I have says pin 6 is N/C but it looks like there is a
way to extract a usable PPS but I think I'm going to need and LC filter,
some op amps and a one-shot and a TTL level driver.   My guess is that pin
6 is either some kind of engineering test/diagnostic signal not intended to
use used or the signal is an accident





   ---Original Message---
   From: David davidwh...@gmail.com
   To: Discussion of precise time and frequency measurement 
 time-nuts@febo.com
   Subject: Re: [time-nuts] FE-5680A performance
   Sent: 05 Jan '12 07:49
 
   On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
   hmur...@megapathdsl.net wrote:
 
   albertson.ch...@gmail.com said:
   
Have an older Tek 465 scope that is in only fair shape and I see
 nothing
on that pin but milivolt level sine wave of about 60MHz.  I can't
 set the
scope to show any hint of a PPS ...
   
   I do have a 465.  You should be able to see a 1 uSec PPS.
 
   60MHz is about a 6nS rise time and is easily fast enough to see it.
 
   Now turn up the Intensity until you can see the pulse.  It might help
 to turn
   down the room lights.
 
   This is the problem.  With a 1 second repetition rate, the brightness
   is going to be very low.
 
   The old ways of viewing such a low repetition rate signal include
   using a hood or dark room, special CRT phosphors, photographic film,
   MCP (micro channel plate) intensified CRTs, and of course analog
   storage and later digital storage.
 
   ___
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-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] FE-5680A performance

On Thu, 05 Jan 2012 18:54:31 +0100, EB4APL
eb4...@cembreros.jazztel.es wrote:

On 05/01/2012 16:49, David wrote:
 On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
 hmur...@megapathdsl.net  wrote:

 albertson.ch...@gmail.com said:
 Have an older Tek 465 scope that is in only fair shape and I see nothing
 on that pin but milivolt level sine wave of about 60MHz.  I can't set the
 scope to show any hint of a PPS ...
 I do have a 465.  You should be able to see a 1 uSec PPS.
 60MHz is about a 6nS rise time and is easily fast enough to see it.

 Now turn up the Intensity until you can see the pulse.  It might help to 
 turn
 down the room lights.
 This is the problem.  With a 1 second repetition rate, the brightness
 is going to be very low.

 The old ways of viewing such a low repetition rate signal include
 using a hood or dark room, special CRT phosphors, photographic film,
 MCP (micro channel plate) intensified CRTs, and of course analog
 storage and later digital storage.

I agree, I've seen it in a Tek 7623A with the storage on, it is quite 
difficult without it.

I can not imagine using my worn 7603 to see it.  I rebuilt a 7834
analog storage oscilloscope for just that sort of application although
I have a 2230 analog/DSO that I repaired which would be easier to use
for this.  I just checked and in analog mode, my 2230 can display a
1uS/div sweep at a 1 second interval without trace thickening in room
light but it is dim enough that I sure would not want to use it for
other than verfying the pulse is there.

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

If you use a Tektronix TDS series scope you can set the acquiring to peak
detect instead of sample to let the PPS be visible even for long timebase
run. That is: usually, with the trigger set to normal and the timebase to
100nS/div or 1uS/div you can see the PPS anyway. If you set the timebase to
100mS/div then you can no longer see the pulse even if the trigger triggers
the scan: setting the acquire to peak detect then the pulse returns
visible and you can see the repetition rate.

On Thu, Jan 5, 2012 at 7:17 PM, Chris Albertson
albertson.ch...@gmail.comwrote:

 On Thu, Jan 5, 2012 at 9:46 AM, beale be...@bealecorner.com wrote:

  I think there is something funny about the 1 PPS output on pin 6 from the
  currently available cheap FE-5680A units. I have three of these units. On
  one unit, on one occasion, I did observe a logic-level 1 PPS pulse,
 exactly
  1 microsecond wide.  But after a power cycle it never came back, although
  the unit indicates a locked condition, and is apparently working. The
 other
  two units also seem to work (10 MHz output OK, lock OK) but I have never
  seen a 1 PPS signal on pin 6 from them. My Tek TDS-210 is easily capable
 of
  triggering on and displaying a 1 usec pulse.  Is it possible the pulse
  appears only after a RS-232 command, or after some other special
 condition?


 I think the signal is there, it is just very small

 I tried again this morning.  On mine the pulse is there but it's very weak.
  I can't see it one the scope but I can see the trigger light flash every
 second if I work to set it just right.  I also see an about 0.3V peak to
 peak, about 60MHz sine wave.   I can get the scope to trigger and display
 the sine wave just fine.  I have to use a 10X scope probe or I load the
 signal to millivolts

 The PPS signal coming from my Oncore GPS is easy to see on my scope and
 even on a DMM set to DC Volts

 The FE-5680's PPS is not usable directly with my counter, I have to amplify
 it then set the counter to 10X attenuation then mess with the trigger
 setting so it does not see the 60MHz signal. Maybe I'm lucky that my
 scope has a BNC output on the back for the vertical amplifier, so I can
 apply a 20MHz low pass filter and about 20X voltage gain.

 The documentation I have says pin 6 is N/C but it looks like there is a
 way to extract a usable PPS but I think I'm going to need and LC filter,
 some op amps and a one-shot and a TTL level driver.   My guess is that pin
 6 is either some kind of engineering test/diagnostic signal not intended to
 use used or the signal is an accident




 
---Original Message---
From: David davidwh...@gmail.com
To: Discussion of precise time and frequency measurement 
  time-nuts@febo.com
Subject: Re: [time-nuts] FE-5680A performance
Sent: 05 Jan '12 07:49
  
On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
hmur...@megapathdsl.net wrote:
  
albertson.ch...@gmail.com said:

 Have an older Tek 465 scope that is in only fair shape and I see
  nothing
 on that pin but milivolt level sine wave of about 60MHz.  I can't
  set the
 scope to show any hint of a PPS ...

I do have a 465.  You should be able to see a 1 uSec PPS.
  
60MHz is about a 6nS rise time and is easily fast enough to see it.
  
Now turn up the Intensity until you can see the pulse.  It might help
  to turn
down the room lights.
  
This is the problem.  With a 1 second repetition rate, the brightness
is going to be very low.
  
The old ways of viewing such a low repetition rate signal include
using a hood or dark room, special CRT phosphors, photographic film,
MCP (micro channel plate) intensified CRTs, and of course analog
storage and later digital storage.
  
___
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 --

 Chris Albertson
 Redondo Beach, California
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Re: [time-nuts] Navsync CW12 - More Info

Great, don't forget to specify what reference your measurements were made
from (or did I miss anything from your posts?).
We use the CW12 PPS for our GPSDOs.

On Thu, Jan 5, 2012 at 6:57 PM, Ed Palmer ed_pal...@sasktel.net wrote:

 Okay, I've cooled off - a bit.  The bottom line is that the 10 MHz output
 of the CW12 isn't appropriate for what I wanted to do.  Ah, the joys of
 reading and understanding a spec sheet!

 But let's not throw out the baby with the bathwater.  Although the 10 MHz
 output has it's issues for typical Time-Nut applications, the 1 PPS output
 is great.  Here are some measurements that I've made over the past few
 years on a few GPS receivers and a couple of GPSDOs.  I measure 1000
 periods of the 1 PPS and look at the results.  Every run gives somewhat
 different results so I've shown some typical ranges.  These measurements
 were made with an HP 5372A.  YMMV.

 Device .. Std Dev (ns) Range (max-min)(ns) ... Device Type

 Navsync CW12  4 - 5 .. 20 - 25 ... GPS Rcvr
 Motorola UT+  40 - 55  95 - 110 .. GPS Rcvr *
 see below
 Rockwell Jupiter  10   50 ...  GPS Rcvr **
 Motorola M12M ... 10 - 15  40 - 60 ... GPS Rcvr

 Trimble Thunderbolt . 0.4 - 0.5 .. 2 - 4 . GPSDO
 HP Z3801A ... 0.3  2 . GPSDO***


 *   Most of my UT+ 'range' results were in this group, but there were a
 few at 20 - 30.
 **  Only one result.
 *** Only one result.  I need to do more testing on the Z3801A


 As you can see, the Navsync CW12 is by far the best of the GPS Receivers,
 but nowhere near as good as the GPSDOs.  However, imagine using the CW12 to
 discipline a good OCXO to build your own GPSDO.  Or using it to discipline
 a PRS10 Rubidium or X72 Rubidium oscillator.  You can't do it with the 10
 MHz output, but the 1 PPS output is another story.

 Ed




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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

The 2230 like I have was the earliest Tektronix oscilloscope with peak
detect that I know of.  Everything after it with some odd exceptions
like the TDS 620 series included peak detect.

I bought and fixed the 2230 instead of a new Rigol just for the peak
detect.  The low end Rigol oscilloscopes have envelope detect but it
is not clear if it includes peak detect when operating in that mode.

On Thu, 5 Jan 2012 19:47:28 +0100, Azelio Boriani
azelio.bori...@screen.it wrote:

If you use a Tektronix TDS series scope you can set the acquiring to peak
detect instead of sample to let the PPS be visible even for long timebase
run. That is: usually, with the trigger set to normal and the timebase to
100nS/div or 1uS/div you can see the PPS anyway. If you set the timebase to
100mS/div then you can no longer see the pulse even if the trigger triggers
the scan: setting the acquire to peak detect then the pulse returns
visible and you can see the repetition rate.

On Thu, Jan 5, 2012 at 7:17 PM, Chris Albertson
albertson.ch...@gmail.comwrote:

 On Thu, Jan 5, 2012 at 9:46 AM, beale be...@bealecorner.com wrote:

  I think there is something funny about the 1 PPS output on pin 6 from the
  currently available cheap FE-5680A units. I have three of these units. On
  one unit, on one occasion, I did observe a logic-level 1 PPS pulse,
 exactly
  1 microsecond wide.  But after a power cycle it never came back, although
  the unit indicates a locked condition, and is apparently working. The
 other
  two units also seem to work (10 MHz output OK, lock OK) but I have never
  seen a 1 PPS signal on pin 6 from them. My Tek TDS-210 is easily capable
 of
  triggering on and displaying a 1 usec pulse.  Is it possible the pulse
  appears only after a RS-232 command, or after some other special
 condition?

 I think the signal is there, it is just very small

 I tried again this morning.  On mine the pulse is there but it's very weak.
  I can't see it one the scope but I can see the trigger light flash every
 second if I work to set it just right.  I also see an about 0.3V peak to
 peak, about 60MHz sine wave.   I can get the scope to trigger and display
 the sine wave just fine.  I have to use a 10X scope probe or I load the
 signal to millivolts

 The PPS signal coming from my Oncore GPS is easy to see on my scope and
 even on a DMM set to DC Volts

 The FE-5680's PPS is not usable directly with my counter, I have to amplify
 it then set the counter to 10X attenuation then mess with the trigger
 setting so it does not see the 60MHz signal. Maybe I'm lucky that my
 scope has a BNC output on the back for the vertical amplifier, so I can
 apply a 20MHz low pass filter and about 20X voltage gain.

 The documentation I have says pin 6 is N/C but it looks like there is a
 way to extract a usable PPS but I think I'm going to need and LC filter,
 some op amps and a one-shot and a TTL level driver.   My guess is that pin
 6 is either some kind of engineering test/diagnostic signal not intended to
 use used or the signal is an accident

---Original Message---
From: David davidwh...@gmail.com
To: Discussion of precise time and frequency measurement 
  time-nuts@febo.com
Subject: Re: [time-nuts] FE-5680A performance
Sent: 05 Jan '12 07:49
  
On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
hmur...@megapathdsl.net wrote:
  
albertson.ch...@gmail.com said:

 Have an older Tek 465 scope that is in only fair shape and I see
  nothing
 on that pin but milivolt level sine wave of about 60MHz.  I can't
  set the
 scope to show any hint of a PPS ...

I do have a 465.  You should be able to see a 1 uSec PPS.
  
60MHz is about a 6nS rise time and is easily fast enough to see it.
  
Now turn up the Intensity until you can see the pulse.  It might help
  to turn
down the room lights.
  
This is the problem.  With a 1 second repetition rate, the brightness
is going to be very low.
  
The old ways of viewing such a low repetition rate signal include
using a hood or dark room, special CRT phosphors, photographic film,
MCP (micro channel plate) intensified CRTs, and of course analog
storage and later digital storage.

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Re: [time-nuts] FE-5680A performance

2012-01-05 Thread Tom Van Baak

All the wonders of the TSC boxes aside, there is one really annoying 
thing you need to keep in mind when working with the phase data: the box 
applies an arbitrary phase offset that reflects through to the phase 
data output.  It appears as a linear frequency offset that needs to be 
removed prior to doing frequency analysis.  That's not a big problem for 
normal stability measurements, but in some cases it makes it a lot 
harder to extract the data you want.


Right, it has no effect on ADEV plots (which are immune from fixed
phase or fixed frequency offsets).

I see this on the TSC 5120 but not the 5110. Same for you? When
in single DDS mode the 5110 phase is absolute. But when in the
dual DDS mode the raw phase output is scaled by B/A frequency,
which is displayed at the lower right side of the screen. I don't recall
this value changing over time so I'm curious about your fcounter
comments.

John, could you expand on your comment about the ethernet connection?  I 
have seen random instances where the TSC seems to lose its TCP/IP 
settings, but so far it's never happened during a measurement run, so 
has been annoying but manageable.


I totally agree. I had no LAN trouble for many years but when I upgraded
(2005?) to a later TSC firmware my old PC would sometimes loose the
net connection. The RS-232 output is always ok. I tried multiple PC's
and multiple (Windows) OS's and megabytes of TCP traces but never
solved the problem. It's rare but when you make unattended runs it's
very sad to lose days of data due to a TCP connection closing. This is
one reason why (for modest data rates) I still prefer vintage RS232 or
GPIB connections compared to modern USB or LAN connections.

/tvb


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Re: [time-nuts] Navsync CW12 - More Info

2012-01-05 Thread Ed Palmer

Do you mean the reference oscillator for the 5372A?  That was the 
internal 10811 OCXO.  Over a 1000 sec. run, drift wouldn't have any 
affect on these numbers.


Ed

On 1/5/2012 12:54 PM, Azelio Boriani wrote:

Great, don't forget to specify what reference your measurements were made
from (or did I miss anything from your posts?).
We use the CW12 PPS for our GPSDOs.

On Thu, Jan 5, 2012 at 6:57 PM, Ed Palmered_pal...@sasktel.net  wrote:


Okay, I've cooled off - a bit.  The bottom line is that the 10 MHz output
of the CW12 isn't appropriate for what I wanted to do.  Ah, the joys of
reading and understanding a spec sheet!

But let's not throw out the baby with the bathwater.  Although the 10 MHz
output has it's issues for typical Time-Nut applications, the 1 PPS output
is great.  Here are some measurements that I've made over the past few
years on a few GPS receivers and a couple of GPSDOs.  I measure 1000
periods of the 1 PPS and look at the results.  Every run gives somewhat
different results so I've shown some typical ranges.  These measurements
were made with an HP 5372A.  YMMV.

Device .. Std Dev (ns) Range (max-min)(ns) ... Device Type

Navsync CW12  4 - 5 .. 20 - 25 ... GPS Rcvr
Motorola UT+  40 - 55  95 - 110 .. GPS Rcvr *
see below
Rockwell Jupiter  10   50 ...  GPS Rcvr **
Motorola M12M ... 10 - 15  40 - 60 ... GPS Rcvr

Trimble Thunderbolt . 0.4 - 0.5 .. 2 - 4 . GPSDO
HP Z3801A ... 0.3  2 . GPSDO***


*   Most of my UT+ 'range' results were in this group, but there were a
few at 20 - 30.
**  Only one result.
*** Only one result.  I need to do more testing on the Z3801A


As you can see, the Navsync CW12 is by far the best of the GPS Receivers,
but nowhere near as good as the GPSDOs.  However, imagine using the CW12 to
discipline a good OCXO to build your own GPSDO.  Or using it to discipline
a PRS10 Rubidium or X72 Rubidium oscillator.  You can't do it with the 10
MHz output, but the 1 PPS output is another story.

Ed




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Re: [time-nuts] FE-5680A performance

I found it,  I used the +15 V of my triple output supply to power the 
pin 4, +5 V input.  A 75ACT240 popped up and who knows the health of the 
other things.


Wish me luck,
Ignacio, EB4APL


El 05/01/2012 18:54, EB4APL wrote:


I agree, I've seen it in a Tek 7623A with the storage on, it is quite 
difficult without it.


Regards,
Ignacio, EB4APL

PD. Just trying to verify this I made some error and let the magic 
smoke leave the unit. It is still smelling ...






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Re: [time-nuts] FE-5680A performance

Doh!

Hopefully anything directly connected to that 5 volt supply pin can be
replaced if neccessary.

On Thu, 05 Jan 2012 20:37:06 +0100, EB4APL
eb4...@cembreros.jazztel.es wrote:

I found it,  I used the +15 V of my triple output supply to power the 
pin 4, +5 V input.  A 75ACT240 popped up and who knows the health of the 
other things.

Wish me luck,
Ignacio, EB4APL

El 05/01/2012 18:54, EB4APL wrote:

 I agree, I've seen it in a Tek 7623A with the storage on, it is quite 
 difficult without it.

 Regards,
 Ignacio, EB4APL

 PD. Just trying to verify this I made some error and let the magic 
 smoke leave the unit. It is still smelling ...

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Re: [time-nuts] FE-5680A performance - replacing fried chip

2012-01-05 Thread beale

I did something similar- momentary contact of +15V supply with one of the other 
pins- might have been the +5 Vin, or another signal. The 75ACT240 became very 
hot. I ordered a replacement 75ACT240 part, swapped it in, and the unit seems 
to work fine now.  Note this is the 0.3 wide device, DigiKey p/n 
74ACT240SC-ND.  Confusingly, that part in 20-pin SOIC is made in two different 
body widths: 0.209 / 5.3 mm and 0.295 / 7.5 mm.

This photo shows the board with the smoked chip removed (U503 at upper left), 
before I installed the replacement
https://picasaweb.google.com/lh/photo/mF9WSGlEQjA8MqHhbPOJRdMTjNZETYmyPJy0liipFm0?feat=directlink

-john

  ---Original Message---
  From: EB4APL eb4...@cembreros.jazztel.es
  To: time-nuts@febo.com
  Subject: Re: [time-nuts] FE-5680A performance
  Sent: 05 Jan '12 11:37
  
  I found it,  I used the +15 V of my triple output supply to power the
  pin 4, +5 V input.  A 75ACT240 popped up and who knows the health of the
  other things.
  
  Wish me luck,
  Ignacio, EB4APL
  
  
  El 05/01/2012 18:54, EB4APL wrote:
  
   I agree, I've seen it in a Tek 7623A with the storage on, it is quite
   difficult without it.
  
   Regards,
   Ignacio, EB4APL
  
   PD. Just trying to verify this I made some error and let the magic
   smoke leave the unit. It is still smelling ...
  
  
  
  
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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

2012-01-05 Thread WarrenS



Yes almost as long as you include ONE more Resistor, R2 added below.
The dual cap thing does not get rid of leakage entirely, but close enough in 
most cases.
That configuration is most useful for slow open loop filters when you want 
low leakage errors.


It may be a bit of an overkill for a closed loop filters when a 10 % 
leakage would be tolerable.
I tested a 10,000 sec TC filter using a 10 meg and 1000 uF, and got under 1% 
leakage error open loop.


ws

***

[time-nuts] Thunderbolt? (re simple gpsdo.)  capacitors
Poul-Henning Kamp phk at phk.freebsd.dk

The leakage current noise I measured was way below insignificant when 
things are properly scaled.


Couldn't the double condensor from voltage references trick be used to 
eliminate the leakage entirely ?



[Some op-amp]  -+-R2-+--
  |  |
  |   -
  |   -
  |  |
 +---||---+
|
 -
 -
|
GND
--
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20 



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Re: [time-nuts] Navsync CW12 - More Info

OK, thank you.

On Thu, Jan 5, 2012 at 8:29 PM, Ed Palmer ed_pal...@sasktel.net wrote:

 Do you mean the reference oscillator for the 5372A?  That was the internal
 10811 OCXO.  Over a 1000 sec. run, drift wouldn't have any affect on these
 numbers.

 Ed


 On 1/5/2012 12:54 PM, Azelio Boriani wrote:

 Great, don't forget to specify what reference your measurements were made
 from (or did I miss anything from your posts?).
 We use the CW12 PPS for our GPSDOs.

 On Thu, Jan 5, 2012 at 6:57 PM, Ed Palmered_pal...@sasktel.net  wrote:

  Okay, I've cooled off - a bit.  The bottom line is that the 10 MHz output
 of the CW12 isn't appropriate for what I wanted to do.  Ah, the joys of
 reading and understanding a spec sheet!

 But let's not throw out the baby with the bathwater.  Although the 10 MHz
 output has it's issues for typical Time-Nut applications, the 1 PPS
 output
 is great.  Here are some measurements that I've made over the past few
 years on a few GPS receivers and a couple of GPSDOs.  I measure 1000
 periods of the 1 PPS and look at the results.  Every run gives somewhat
 different results so I've shown some typical ranges.  These measurements
 were made with an HP 5372A.  YMMV.

 Device .. Std Dev (ns) Range (max-min)(ns) ... Device
 Type

 Navsync CW12  4 - 5 .. 20 - 25 ... GPS Rcvr
 Motorola UT+  40 - 55  95 - 110 .. GPS Rcvr *
 see below
 Rockwell Jupiter  10   50 ...  GPS Rcvr
 **
 Motorola M12M ... 10 - 15  40 - 60 ... GPS Rcvr

 Trimble Thunderbolt . 0.4 - 0.5 .. 2 - 4 . GPSDO
 HP Z3801A ... 0.3  2 . GPSDO
  ***


 *   Most of my UT+ 'range' results were in this group, but there were a
 few at 20 - 30.
 **  Only one result.
 *** Only one result.  I need to do more testing on the Z3801A


 As you can see, the Navsync CW12 is by far the best of the GPS Receivers,
 but nowhere near as good as the GPSDOs.  However, imagine using the CW12
 to
 discipline a good OCXO to build your own GPSDO.  Or using it to
 discipline
 a PRS10 Rubidium or X72 Rubidium oscillator.  You can't do it with the 10
 MHz output, but the 1 PPS output is another story.

 Ed




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Re: [time-nuts] FE-5680A performance - replacing fried chip

John,

You are not alone in this trip. Another member of this list tells me
that he connected the power to the lock indicator pin when he received
his unit and he was eager to test it. His 74ACT240 also got cooked but
the rest of the unit continued working normally.
Well, mine seems to have the same good luck. It lits the Rb lamp, the
temperature controller takes the normal current, the oscillator sweeps
back and forth and then the unit LOCKS!. I only have missing the Lock
indicator and the PPS.
And to continue the original test, I checked the PPS this time at the
input of the buffer (74ACT240 pin 2) and it is there but very difficult
to see without a storage or digital scope, the duty cycle is too low.
Anyway the trigger light is a tell tale.
And thank you for your tip about the chip type, I have to order one and
replace it because I want the PPS and the lock indicator, and maybe some
other buffers are used inside for minor functions.

BTW, maybe the units who lack the PPS have this output damaged, because
some info list this pin as power input and it seems to be true but in
other FE-5680 variants. Who knows why FE designed so different units
with the same number.

Best Regards,
Ignacio, EB4APL

On 05/01/2012 21:10, beale wrote:

I did something similar- momentary contact of +15V supply with one of the other pins- might
have been the +5 Vin, or another signal. The 75ACdT240 became very hot. I ordered a
replacement 75ACT240 part, swapped it in, and the unit seems to work fine now. Note this is
the 0.3 wide device, DigiKey p/n 74ACT240SC-ND. Confusingly, that part in 20-pin SOIC
is made in two different body widths: 0.209 / 5.3 mm and 0.295 / 7.5 mm.

This photo shows the board with the smoked chip removed (U503 at upper left),
before I installed the replacement
https://picasaweb.google.com/lh/photo/mF9WSGlEQjA8MqHhbPOJRdMTjNZETYmyPJy0liipFm0?feat=directlink

-john

---Original Message---
From: EB4APLeb4...@cembreros.jazztel.es
To: time-nuts@febo.com
Subject: Re: [time-nuts] FE-5680A performance
Sent: 05 Jan '12 11:37

I found it, I used the +15 V of my triple output supply to power the
pin 4, +5 V input. A 75ACT240 popped up and who knows the health of the
other things.

Wish me luck,
Ignacio, EB4APL

El 05/01/2012 18:54, EB4APL wrote:

I agree, I've seen it in a Tek 7623A with the storage on, it is quite
difficult without it.

Regards,
Ignacio, EB4APL

PD. Just trying to verify this I made some error and let the magic
smoke leave the unit. It is still smelling ...

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Re: [time-nuts] FE-5680A performance

2012-01-05 Thread SAIDJACK

Hello Tom,
 
haven't tried the raw data capture yet. It would be nice if they would have 
 added support for USB thumb drives to store this type of data, and plots  
etc.
 
But it does have internal RAM, they could have allocated a Mbyte or so for  
data-storage..
 
BTW: my unit used to reset itself all the time also. It was impossible to  
get measurements longer than a couple of days. After I got many hardware 
error  warnings on the screen, Symmetricom fixed it after several attempts by 
replacing  the AT processor board, and updating the flash firmware... Also, I 
had one flash  drive die on me as well.. I also remember a correlation to 
ambient temperature,  higher temps made it crash more often.
 
Will look at John's Timelab asap..
 
Thanks,
Said
 
 
In a message dated 1/4/2012 21:46:54 Pacific Standard Time,  
t...@leapsecond.com writes:

 I  also don't like the way the TSC shows the frequency, and the fact that 
  
 you can only capture about 9 minutes of information for some reason.  Why 
not  
 show 24 hours or 48 hours of data  here?

Said,

The 9+ minutes (540+ seconds) is due to the 640  pixel display
minus the soft menu that appears on the right side.  

The TSC doesn't save all the raw data from the run and thus  you
can't pan or zoom over the data like you would expect. Note there
is  no harddrive in the TSC (the CF card is just a boot filesystem).

So  there are two tricks you can use. The first is what I do, which
is to  capture all the raw phase data from the TSC, logging it on PC,
and then use  Stable32 or TimeLab to manipulate or plot as much
or as little of the data  as desired. Many of the plots on my web site
are created this way. I almost  always begin a log of raw data before
I press start on a TSC analyzer. That  way I have a permanent copy
of all the phase data, from which all other  analysis is based.

Depending on the model of TSC, the raw phase data is  delivered
by RS-232 or LAN at rates of 1 Hz, 100 Hz, or 1 kHz. For  really
long runs (days or weeks, even months) I typically use 1  Hz.

The second solution, one I would strongly recommend, is to  use
the live capture capability in TimeLab. John has built-in  support
for a number of popular counters, including the TSC. I'm  pretty
sure you can get it going in a matter of minutes; you will  never
look  back.

/tvb

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Re: [time-nuts] FE-5680A performance

2012-01-05 Thread SAIDJACK

Will try it John!

Thanks,
Said
 
 
In a message dated 1/4/2012 21:35:00 Pacific Standard Time, jmi...@pop.net  
writes:

Grab the  latest release from www.miles.io/timelab/readme.htm if you like --
it will  acquire from the TSC 5125A for as many hours/days as the TSC's
Ethernet  connection will stay up.  (Which sometimes isn't very long.)   

TimeLab generates its frequency-difference plot from the acquired  phase
data, so it will give you various display and filtering options that  the
5125A itself will not.

-- john
Miles Design  LLC

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

2012-01-05 Thread bg

Hi Chris,

 The documentation I have says pin 6 is N/C but it looks like there is a
 way to extract a usable PPS but I think I'm going to need and LC filter,
 some op amps and a one-shot and a TTL level driver.   My guess is that pin
 6 is either some kind of engineering test/diagnostic signal not intended
 to use used or the signal is an accident.

I have two of the older generation. Here the ONLY output is a 1PPS, which
is divided by a fixed 2^23 from the internal DDS-generated frequency
(8.3xxxMHz). It is not possible to get both 10MHz and a 1PPS at the same
time. On the other hand the 8.3xxxMHz is tunable over many MHz.

(One of the units is also suffering from a mishap. 15V connected to the
1PPS output did some damage.)

--

Björn



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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

I have googled extensively trying to find something about the dual
capacitor method of reducing the leakage current... nothing found. Please,
can you indicate anything for me to learn more?
Thank you

On Thu, Jan 5, 2012 at 9:18 PM, WarrenS warrensjmail-...@yahoo.com wrote:


 Yes almost as long as you include ONE more Resistor, R2 added below.
 The dual cap thing does not get rid of leakage entirely, but close enough
 in most cases.
 That configuration is most useful for slow open loop filters when you want
 low leakage errors.

 It may be a bit of an overkill for a closed loop filters when a 10 %
 leakage would be tolerable.
 I tested a 10,000 sec TC filter using a 10 meg and 1000 uF, and got under
 1% leakage error open loop.

 ws


 ***

 [time-nuts] Thunderbolt? (re simple gpsdo.)  capacitors
 Poul-Henning Kamp phk at phk.freebsd.dk


  The leakage current noise I measured was way below insignificant when
 things are properly scaled.


  Couldn't the double condensor from voltage references trick be used to
 eliminate the leakage entirely ?



 [Some op-amp]  -+-R2-+--
  |  |
  |   -
  |   -
  |  |
 +---||---+

|
 -
 -
|
GND
 --
 Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

On Thu, Jan 5, 2012 at 1:48 PM, b...@lysator.liu.se wrote:

 Hi Chris,

  The documentation I have says pin 6 is N/C but it looks like there is a
  way to extract a usable PPS but I think I'm going to need and LC filter,
  some op amps and a one-shot and a TTL level driver.   My guess is that
 pin
  6 is either some kind of engineering test/diagnostic signal not intended
  to use used or the signal is an accident.

 I have two of the older generation. Here the ONLY output is a 1PPS, which
 is divided by a fixed 2^23 from the internal DDS-generated frequency
 (8.3xxxMHz). It is not possible to get both 10MHz and a 1PPS at the same
 time. On the other hand the 8.3xxxMHz is tunable over many MHz.

 (One of the units is also suffering from a mishap. 15V connected to the
 1PPS output did some damage.)


My guess is that these all have the same part numbers because the hardware
is the same.  But one chip is a CPLD which might have some very different
programming depending on what the customer needed  I see some components
where never installed on my unit, so it maybe more than just programming.


 --

Björn



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-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] FE-5680A performance

2012-01-05 Thread Hal Murray

(Context is using a Tek 465 to look at a narrow PPS.)

davidwh...@gmail.com said:
 Now turn up the Intensity until you can see the pulse.  It might
 help to turn down the room lights.

 This is the problem.  With a 1 second repetition rate, the brightness is
 going to be very low.

For me, the picture is just a flash every second, but my eye/brain can easily 
remember enough to figure out what's going on.

If I turn the intensity up enough, the beam in the idle position bleeds 
through the blanking and you can see where it is resting.  (For things like 
this, I set the horizontal position with the beam well on screen.)

With that as a starting point, it is easy to estimate the pulse polarity, 
height, and width.  If you want to look at a detail, you have to look at the 
right place on the screen and wait for the next flash.  It may take several 
tries and/or a bit of practice.

Yes, I would go nuts if I had to do this very often, but it's good enough for 
occasional use.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.




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[time-nuts] Leap second

2012-01-05 Thread Jim Palfreyman

Leap second has been announced for July.

Jim
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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

2012-01-05 Thread lists

Perhaps the dual cap is a differential implementation of the filter/integrator. 

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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

... don't know but judging from the very simple ASCII schematic I'll say no
because the lower capacitor is grounded. There is some sort of feedback I
can't figure out, too simple that schematic.

On Thu, Jan 5, 2012 at 11:27 PM, li...@lazygranch.com wrote:

 Perhaps the dual cap is a differential implementation of the
 filter/integrator.

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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

2012-01-05 Thread Poul-Henning Kamp

In message 
CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com
, Azelio Boriani writes:

I have googled extensively trying to find something about the dual
capacitor method of reducing the leakage current... nothing found. Please,
can you indicate anything for me to learn more?

It is very simple:

R1 charges C1 to the DC potential and therefore C2 sees
(almost) no DC voltage, which means (almost) no leakage
current.  C2 is still a capacitor for any AC or dV component.

I belive I picked this trick up from a datasheet or app-note relating
to precision voltage references.

Poul-Henning

 [Some op-amp]  -+-R2-+--
  ||
  |  - C2
  |  -
  ||
  +---||---+
R1 |
   |
 -  C1
 -
   |
  GND

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

2012-01-05 Thread bg

Chris,

 On Thu, Jan 5, 2012 at 1:48 PM, b...@lysator.liu.se wrote:

 Hi Chris,

  The documentation I have says pin 6 is N/C but it looks like there
 is a
  way to extract a usable PPS but I think I'm going to need and LC
 filter,
  some op amps and a one-shot and a TTL level driver.   My guess is that
 pin
  6 is either some kind of engineering test/diagnostic signal not
 intended
  to use used or the signal is an accident.

 I have two of the older generation. Here the ONLY output is a 1PPS,
 which
 is divided by a fixed 2^23 from the internal DDS-generated frequency
 (8.3xxxMHz). It is not possible to get both 10MHz and a 1PPS at the same
 time. On the other hand the 8.3xxxMHz is tunable over many MHz.

 (One of the units is also suffering from a mishap. 15V connected to the
 1PPS output did some damage.)


 My guess is that these all have the same part numbers because the hardware
 is the same.  But one chip is a CPLD which might have some very different
 programming depending on what the customer needed  I see some components
 where never installed on my unit, so it maybe more than just programming.

No, there are two different generations. The older based on 50.xxx MHz,
the newer on 60.0MHz (?) The older has a lot of stacked daughtercards on
the digital side. There are many differend sub-versions of these as well.
The newer generation seem to be one clean PCB. Look for picture links in
the recent archives.

--

   Björn


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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

2012-01-05 Thread paul swed

Poul
Thanks have been kind of following this thread and the diagram did not make
a lot of sense.
I figured I missed part of the thread. But this clears it up nicely.
Regards
Paul.
WB8TSL

On Thu, Jan 5, 2012 at 5:49 PM, Poul-Henning Kamp p...@phk.freebsd.dkwrote:

 In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=
 g...@mail.gmail.com
 , Azelio Boriani writes:

 I have googled extensively trying to find something about the dual
 capacitor method of reducing the leakage current... nothing found. Please,
 can you indicate anything for me to learn more?

 It is very simple:

 R1 charges C1 to the DC potential and therefore C2 sees
 (almost) no DC voltage, which means (almost) no leakage
 current.  C2 is still a capacitor for any AC or dV component.

 I belive I picked this trick up from a datasheet or app-note relating
 to precision voltage references.

 Poul-Henning

  [Some op-amp]  -+-R2-+--
   ||
   |  - C2
   |  -
   ||
   +---||---+
 R1 |
|
  -  C1
  -
|
   GND

 --
 Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
 p...@freebsd.org | TCP/IP since RFC 956
 FreeBSD committer   | BSD since 4.3-tahoe
 Never attribute to malice what can adequately be explained by incompetence.

 ___
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 To unsubscribe, go to
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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

Thanks. Me too: now I got it, sort of bootstrap and now I see that R2 is
needed because the real filter is R2*C2 and the leakage is not totally
compensated if C1 has to move to a new value - R*C1R2*C2.

On Fri, Jan 6, 2012 at 12:00 AM, paul swed paulsw...@gmail.com wrote:

 Poul
 Thanks have been kind of following this thread and the diagram did not make
 a lot of sense.
 I figured I missed part of the thread. But this clears it up nicely.
 Regards
 Paul.
 WB8TSL

 On Thu, Jan 5, 2012 at 5:49 PM, Poul-Henning Kamp p...@phk.freebsd.dk
 wrote:

  In message CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=
  g...@mail.gmail.com
  , Azelio Boriani writes:
 
  I have googled extensively trying to find something about the dual
  capacitor method of reducing the leakage current... nothing found.
 Please,
  can you indicate anything for me to learn more?
 
  It is very simple:
 
  R1 charges C1 to the DC potential and therefore C2 sees
  (almost) no DC voltage, which means (almost) no leakage
  current.  C2 is still a capacitor for any AC or dV component.
 
  I belive I picked this trick up from a datasheet or app-note relating
  to precision voltage references.
 
  Poul-Henning
 
   [Some op-amp]  -+-R2-+--
||
|  - C2
|  -
||
+---||---+
  R1 |
 |
   -  C1
   -
 |
GND
 
  --
  Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
  p...@freebsd.org | TCP/IP since RFC 956
  FreeBSD committer   | BSD since 4.3-tahoe
  Never attribute to malice what can adequately be explained by
 incompetence.
 
  ___
  time-nuts mailing list -- time-nuts@febo.com
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  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] FE-5680A performance - replacing fried chip

2012-01-05 Thread C. Turner

I, too, am one that cleverly managed to cook the '240 chip:  Too many 
clip leads in too small a space allowed the +15 to get into the lock 
indicator pin while I was evaluating the unit.  It, too, worked OK after 
doing that.


Rather than order another 74ACT240 or even just an HC/T240, I rummaged 
around and found a 74LS240 and replaced it, making good use of my hot 
air rework tool:  Removing the old chip and installing the new one was 
far easier than it would have been had it been an un-socketed DIP!


I suppose I should be slightly concerned about mixing logic families, 
but I can't seem to get myself too concerned about it:  The lock 
indicator and 1pps outputs work fine and I doubt that I'd really care 
about a few extra nanoseconds here and there and the 'LS doesn't really 
hog too much current compared to the entire unit, anyway...


(FWIW, I can see the 1PPS on my ancient '465B scope, but having dim room 
lighting and turning up the trace intensity to full brightness helps:  
It *really* is hard to see, but it's 1uS wide, just as it should be.)


* * *

On random things, on one of my units it had the section of the board 
populated with the +5V switching regulator - but it was not powered up:  
A bit of sleuthing around with an ohmmeter and with the help of the data 
sheet for the regulator chip revealed which two jumpers needed to be 
installed and I was in business.  If someone else has the 10 MHz only 
5680A with the un-powered 5 volt switcher on board and wants to know 
which jumpers to install, I could make that information available if it 
isn't to be found elsewhere.


The other identical '5680A unit had that portion of the board 
unpopulated, but a few minutes with a soldering iron, 7805, a pair of 
0.1uF monolithics and some wire-wrap wire brought that one online as 
well with the tab of the 7805 soldered to the ground plane in the area 
where the parts weren't and with a bit of heat sink compound on both the 
body of the regulator and the same section of the insulating sheet 
allows at least some of the heat to be transferred to the bottom panel.  
Since then, I've modified another in the same way and also had good results.


I was initially concerned about dumping a couple more watts of heat into 
the box, but attached to any semblance of a heat sink, it's no big deal 
- but I suppose that the extra 100-ish mA above what a switcher might 
pull is a bit annoying...  (When warmed up, the steady-state current at 
15-18 volts stays constant at 800mA for each of the units with the 
in-built 7805.)


73,

Clint
KA7OEI

EB4APLeb4...@cembreros.jazztel.es  said:



John,

You are not alone in this trip.  Another member of this list tells me
that he connected  the power to the lock indicator pin when he received
his unit and he was eager to test it.  His 74ACT240 also got cooked but
the rest of the unit continued working normally.



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[time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread Ian Bobbitt

Can anyone recommend how to power one of the latest crop of 2nd hand
FE-5680As? Are they the ones that need only 15-18vdc, or do they need the
5v line as well?
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[time-nuts] TSC Peculiarities (was Re: FE-5680A performance)

2012-01-05 Thread John Ackermann N8UR


Tom Van Baak said the following on 01/05/2012 02:27 PM:

John, could you expand on your comment about the ethernet connection?
I have seen random instances where the TSC seems to lose its TCP/IP
settings, but so far it's never happened during a measurement run, so
has been annoying but manageable.


I totally agree. I had no LAN trouble for many years but when I upgraded
(2005?) to a later TSC firmware my old PC would sometimes loose the
net connection. The RS-232 output is always ok. I tried multiple PC's
and multiple (Windows) OS's and megabytes of TCP traces but never
solved the problem. It's rare but when you make unattended runs it's
very sad to lose days of data due to a TCP connection closing. This is
one reason why (for modest data rates) I still prefer vintage RS232 or
GPIB connections compared to modern USB or LAN connections.


I've seen delays in the phase data output, but increasing the TCP 
session timeout to a ridiculous level seems to address those -- I think 
my collection program (using the Perl telnet module) sets the timeout to 
30 or 40 seconds.  I recall that when I was playing with it all the 
phase data eventually showed up, but it came in bursts that often had a 
long delay between them.


What's been more annoying is that sometimes the box seems to forget its 
IP parameters; I normally noticed this after a reboot, but it happened 
once when the unit had been continuously powered.  I haven't noticed it 
for a while, so am knocking on wood.


John

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Re: [time-nuts] Power supply for 'Bay FE-5680A?


If it is labeled FEI P/N 217400-30352-1 the response is yes.

Ignacio, EB4APL


On 06/01/2012 1:55, Ian Bobbitt wrote:

Can anyone recommend how to power one of the latest crop of 2nd hand
FE-5680As? Are they the ones that need only 15-18vdc, or do they need the
5v line as well?
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[time-nuts] TSC Peculiarities (was Re: FE-5680A performance)

2012-01-05 Thread John Ackermann N8UR


Tom Van Baak said the following on 01/05/2012 02:27 PM:


I see this on the TSC 5120 but not the 5110. Same for you? When
in single DDS mode the 5110 phase is absolute. But when in the
dual DDS mode the raw phase output is scaled by B/A frequency,
which is displayed at the lower right side of the screen. I don't recall
this value changing over time so I'm curious about your fcounter
comments.


I only have the 5120 as a reference point, and it doesn't have the 
single vs. dual mode or show the frequency scaling.


I was referring to the frequency counter screen on the 5120, which you 
can dump via ethernet.  I wrote a program to poll the box, capture the 
dump, and parse the data into a logfile.


The fcounter screens (for 1, 10, 100, 1000 second averaging) seem to 
update every few seconds.  I usually log every ten seconds and that 
seems to give reliable results.


John

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Re: [time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread Bob Smither

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

EB4APL wrote:
 If it is labeled FEI P/N 217400-30352-1 the response is yes.

Ditto - this is the same P/N of the one I have.  It takes both a 15 V and a 5 V
supply.

The pin numbers reported here earlier are correct:

PIN 1:  INPUT +15V to +18V
PIN 2:  GROUND
PIN 3:  LOCK/UNLOCK (high = unlock)
PIN 4:  INPUT +5V
PIN 5:  GROUND
PIN 7:  OUTPUT ( 10MHz sinewave )

Pin 6 has a (weak) 1pps.  Pins 8 and 9 are for the RS232 interface.

- --
Bob Smither, PhD   Circuit Concepts, Inc.
=
  Q.:  What do the Chaplains of the United States Senate and House of
   Representatives do?
  A.:  They stand at the rostrum, look at the legislators, and pray for
   the country.
=
smit...@c-c-i.com  http://www.C-C-I.Com  281-331-2744(office)  -4616(fax)
-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.5 (GNU/Linux)
Comment: Using GnuPG with CentOS - http://enigmail.mozdev.org

iD8DBQFPBlE9smY7BY+CYksRAj8DAJsEBIY+LsxxjpvbwfBNogmBZ3n8NgCgl4Mj
u74wNlr2NN4ATEZIz823WC8=
=/bw0
-END PGP SIGNATURE-
attachment: smither.vcf___
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Re: [time-nuts] FE-5680A performance - replacing fried chip

On Thu, Jan 5, 2012 at 4:44 PM, C. Turner tur...@ussc.com wrote:


 On random things, on one of my units it had the section of the board
 populated with the +5V switching regulator - but it was not powered up:  A
 bit of sleuthing around with an ohmmeter and with the help of the data
 sheet for the regulator chip revealed which two jumpers needed to be
 installed and I was in business.  If someone else has the 10 MHz only
 5680A with the un-powered 5 volt switcher on board and wants to know which
 jumpers to install,


What's the purpose of either enabling the regulator or installing a 7805?
 Is it just so that you don't need to put 5V on the DB9 connector?


-- 

Chris Albertson
Redondo Beach, California
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[time-nuts] Thunderbolt? (re simple gpsdo.)

2012-01-05 Thread ed breya

Anyone contemplating building an analog loop for a GPSDO should 
consider that it can be very tricky and expensive to attain great 
performance. That's why the commercial ones are primarily digital - 
it puts the most severe performance requirements in the least amount 
of analog circuitry - the DAC, reference, output filter and buffer circuits.


Years ago I had planned to build one using an OCXO and the 1 PPS 
signal from a Motorola Oncore GPS receiver. I had figured out pretty 
much the whole thing down to circuitry and critical components, BUT 
quickly concluded that to hold stability, the entire circuit needed 
to be ovenized - not hot, just held at constant temperature. There 
are a lot of tradeoffs involved in the parts - especially the opamps, 
large integrator caps, and references. Because of the large dynamic 
range and resolution needed, the component leakage, bias currents, 
noise, and tempcos were very significant.


In my scheme I had to control the 10 MHz OCXO over +/- 2 Hz 
initially, coarse tuned with selected low TC resistors, then the 
remainder held with a large integrator. The 10 MHz was to be divided 
down to 1 PPS and compared to the GPS signal with a digital 
logarithmic phase detector down to 100 nSec, then an analog 
interpolator below that.


I abandoned the project when I acquired a Z3801A, and was relieved to 
not have to build all of that stuff and thermally control it too. 
Even with a mostly digital system like the Z3801A, there are 
weaknesses in the small analog portion of the circuit that I think 
can be greatly improved.


So, for slightly tweaking an oscillator with a very narrow tuning 
range, an analog loop is OK, using top notch performance opamps and 
integrator capacitors, but to outright replace the typical digital 
system is much more difficult. While it is true that most errors are 
inside the loop so are averaged and eliminated in the very long 
term, a lot can happen in the one second between those synchronizing 
pulses, and over the medium term 1000s of seconds, where each sample 
of correction signal has only a tiny effect, and the integrator is on 
its own to hold steady.


Ed


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Re: [time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread time-nuts

Thanks, but what are people using to feed it? I'm having trouble pinning down 
power requirements. http://www.freqelec.com/rb_osc_fe5680a.html says 32W peak, 
but then also 15-18v@700mA, which doesn't make sense. I'm still waiting on the 
slow boat from China, so I have a while to find a power supply.

On Jan 5, 2012, at 8:23 PM, EB4APL wrote:

 If it is labeled FEI P/N 217400-30352-1 the response is yes.
 
 Ignacio, EB4APL
 
 
 On 06/01/2012 1:55, Ian Bobbitt wrote:
 Can anyone recommend how to power one of the latest crop of 2nd hand
 FE-5680As? Are they the ones that need only 15-18vdc, or do they need the
 5v line as well?


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Re: [time-nuts] Power supply for 'Bay FE-5680A?

On Thu, Jan 5, 2012 at 4:55 PM, Ian Bobbitt time-n...@custodes.info wrote:

 Can anyone recommend how to power one of the latest crop of 2nd hand
 FE-5680As? Are they the ones that need only 15-18vdc, or do they need the
 5v line as well?


The latest batch of $40 units require +5V too.  I measure about 80mA on the
5V  suply.  So you could make 5V with an LM7805 if you have 15 volts
nearby.The 7805 would only burn 800mW.

the 15V supply needs a solid 1.8A for about five minutes. and then drops to
less than 1/2 of that.The spec says 300mV or ripple is alowed

I'd using a lab type bench supply now but my plan is to use a laptop type
supply that has a large coax type DC plug.   I've seen some that
as labeled as 15V, 6Afor $11 (shipped) on eBay  Older Tosiba laptops
used 15V

I don't really like switching supplies like this so I'm thinking of getting
a 24V laptop supply and re-regulating it with a 7815 and a pass transisor
so that the FE5680 sees a linier supply.  In the end I bet I do both.

Real soon now, like tomorrow I'm going to need a supply for a Thunderbolt
too.   I'll likely build two of those as well.



Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Thunderbolt? (re simple gpsdo.) capacitors

2012-01-05 Thread shalimr9

I have used that trick also for HV supplies when leakage through a capacitor 
(typically the capacitor used to compensate the HV divider used for regulation) 
exposed to 10 or 20kV is hard to eliminate.

At the time, I did not know it had already been invented...

Didier KO4BB


Sent from my BlackBerry Wireless thingy while I do other things...

-Original Message-
From: Poul-Henning Kamp p...@phk.freebsd.dk
Sender: time-nuts-boun...@febo.com
Date: Thu, 05 Jan 2012 22:49:55 
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Thunderbolt? (re simple gpsdo.)  capacitors

In message 
CAL8XPmO76XuTETZC=33_v2YWuJGcw8gCvtTDHyae6E4MFb18=g...@mail.gmail.com
, Azelio Boriani writes:

I have googled extensively trying to find something about the dual
capacitor method of reducing the leakage current... nothing found. Please,
can you indicate anything for me to learn more?

It is very simple:

R1 charges C1 to the DC potential and therefore C2 sees
(almost) no DC voltage, which means (almost) no leakage
current.  C2 is still a capacitor for any AC or dV component.

I belive I picked this trick up from a datasheet or app-note relating
to precision voltage references.

Poul-Henning

 [Some op-amp]  -+-R2-+--
  ||
  |  - C2
  |  -
  ||
  +---||---+
R1 |
   |
 -  C1
 -
   |
  GND

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] Power supply for 'Bay FE-5680A?

On Thu, Jan 5, 2012 at 6:11 PM, time-n...@custodes.info wrote:

 l http://www.freqelec.com/rb_osc_fe5680a.html says 32W peak, but then
 also 15-18v@700mA, which doesn't make sense.


It will pull 35W for the first five or so minutes then the current drops
rather suddenly to about 700mA.

I have an analog amp meter on my power supply and I can see a switch over
after the unit heats up.   They must run an internal oven heater full tilt
at first then go into regulated mode.

Some one else said you can cause the FE5680 to draw more power in steady
state mode by adding heat sinking it.  Yes that works.  Seems the FE5680
wants to be at some set temperature and the heat sink means it takes more
power to keep at the set point.   I just let the fe5680 rest on a small
aluminum plate.

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread jmfranke


On start up from cold condition, 15V at 1.8Amps -2.1Amps (27W -31.5W)
Running after warm up, 15V at 800mA (12W)

Plus 5V at 85mA (0.425W)

John WA4WDL

--
From: time-n...@custodes.info
Sent: Thursday, January 05, 2012 9:11 PM
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Subject: Re: [time-nuts] Power supply for 'Bay FE-5680A?

Thanks, but what are people using to feed it? I'm having trouble pinning 
down power requirements. http://www.freqelec.com/rb_osc_fe5680a.html says 
32W peak, but then also 15-18v@700mA, which doesn't make sense. I'm still 
waiting on the slow boat from China, so I have a while to find a power 
supply.


On Jan 5, 2012, at 8:23 PM, EB4APL wrote:


If it is labeled FEI P/N 217400-30352-1 the response is yes.

Ignacio, EB4APL


On 06/01/2012 1:55, Ian Bobbitt wrote:

Can anyone recommend how to power one of the latest crop of 2nd hand
FE-5680As? Are they the ones that need only 15-18vdc, or do they need 
the

5v line as well?



___
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and follow the instructions there.




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Re: [time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread shalimr9

Most laptop supplies operate around 19 or 20 volts. Its a good place to start 
if you want to get 15V through a linear regulator.

I have used Nintendo Wii supplies for 12V applications that require less than 
3.5A. Chinese clones of those can be bought on eBay for less than $10 with 
shipping.

Didier KO4BB

Sent from my BlackBerry Wireless thingy while I do other things...

-Original Message-
From: Chris Albertson albertson.ch...@gmail.com
Sender: time-nuts-boun...@febo.com
Date: Thu, 5 Jan 2012 18:18:04 
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Power supply for 'Bay FE-5680A?

On Thu, Jan 5, 2012 at 4:55 PM, Ian Bobbitt time-n...@custodes.info wrote:

 Can anyone recommend how to power one of the latest crop of 2nd hand
 FE-5680As? Are they the ones that need only 15-18vdc, or do they need the
 5v line as well?


The latest batch of $40 units require +5V too.  I measure about 80mA on the
5V  suply.  So you could make 5V with an LM7805 if you have 15 volts
nearby.The 7805 would only burn 800mW.

the 15V supply needs a solid 1.8A for about five minutes. and then drops to
less than 1/2 of that.The spec says 300mV or ripple is alowed

I'd using a lab type bench supply now but my plan is to use a laptop type
supply that has a large coax type DC plug.   I've seen some that
as labeled as 15V, 6Afor $11 (shipped) on eBay  Older Tosiba laptops
used 15V

I don't really like switching supplies like this so I'm thinking of getting
a 24V laptop supply and re-regulating it with a 7815 and a pass transisor
so that the FE5680 sees a linier supply.  In the end I bet I do both.

Real soon now, like tomorrow I'm going to need a supply for a Thunderbolt
too.   I'll likely build two of those as well.



Chris Albertson
Redondo Beach, California
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Re: [time-nuts] Power supply for 'Bay FE-5680A?

2012-01-05 Thread time-nuts


On Jan 5, 2012, at 9:33 PM, shali...@gmail.com wrote:

 Most laptop supplies operate around 19 or 20 volts. Its a good place to start 
 if you want to get 15V through a linear regulator.
 
 I have used Nintendo Wii supplies for 12V applications that require less than 
 3.5A. Chinese clones of those can be bought on eBay for less than $10 with 
 shipping.
 
 Didier KO4BB
 
 Sent from my BlackBerry Wireless thingy while I do other things...

So a cheap switcher down to 18-20v and a pair of linear regulators to get the 5 
and 15v? I was hoping for something more off-the-shelf; my T-bolt is running 
off the power supply in the TAPR/tvb group buy from a few years ago.
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Re: [time-nuts] FE-5680A performance - 1 PPS output issue

2012-01-05 Thread Robert Benward

You've had more progress than I did, I don't get anything out of pin 6.  I 
did see the levels toggle, but that was about it.  On various websites I 
read to get exactly 1pps, you need a programmable 5680 because it needs to 
be set to something like 8.388MHz (2^23) to divide down properly.  I suspect 
you may not be able to get both; 10MHz and 1pps.


Bob



- Original Message - 
From: beale be...@bealecorner.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Thursday, January 05, 2012 12:46 PM
Subject: Re: [time-nuts]FE-5680A performance - 1 PPS output issue


I think there is something funny about the 1 PPS output on pin 6 from the 
currently available cheap FE-5680A units. I have three of these units. On 
one unit, on one occasion, I did observe a logic-level 1 PPS pulse, exactly 
1 microsecond wide.  But after a power cycle it never came back, although 
the unit indicates a locked condition, and is apparently working. The other 
two units also seem to work (10 MHz output OK, lock OK) but I have never 
seen a 1 PPS signal on pin 6 from them. My Tek TDS-210 is easily capable of 
triggering on and displaying a 1 usec pulse.  Is it possible the pulse 
appears only after a RS-232 command, or after some other special condition?




 ---Original Message---
 From: David davidwh...@gmail.com
 To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

 Subject: Re: [time-nuts] FE-5680A performance
 Sent: 05 Jan '12 07:49

 On Thu, 05 Jan 2012 01:44:13 -0800, Hal Murray
 hmur...@megapathdsl.net wrote:

 albertson.ch...@gmail.com said:
 
  Have an older Tek 465 scope that is in only fair shape and I see 
nothing
  on that pin but milivolt level sine wave of about 60MHz. I can't set 
the

  scope to show any hint of a PPS ...
 
 I do have a 465. You should be able to see a 1 uSec PPS.

 60MHz is about a 6nS rise time and is easily fast enough to see it.

 Now turn up the Intensity until you can see the pulse. It might help to 
turn

 down the room lights.

 This is the problem. With a 1 second repetition rate, the brightness
 is going to be very low.

 The old ways of viewing such a low repetition rate signal include
 using a hood or dark room, special CRT phosphors, photographic film,
 MCP (micro channel plate) intensified CRTs, and of course analog
 storage and later digital storage.

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Re: [time-nuts] FE-5680A performance - 1 PPS output issue