Re: [time-nuts] PTPv2 grandmaster with a Z3805A?

2013-08-21 Thread Poul-Henning Kamp
In message CAHyFsx=5NhAUw_=Xm=YaSPLU=+0ag5dxgkpwwhcrdmjk+d6...@mail.gmail.com
, Wojciech Owczarek writes:

 support for timing electrical signals
 using the same free-running counter as used for the PTP packets.

Sounds interesting. Can you elaborate? Does the card then run its own clock?

Yes, it has a free running counter and can timestamp packets received
and transmitted (if they match a particular filter) and timestamp
(and possibly generate) external signals as well.

Read the datasheet...

or other dedicated timing NICs? What makes it stand out so much - is it
just that
it supports all that's needed without being marketed as a precision timing
NIC?

Price.


-- 
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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[time-nuts] strange hp 5345A option C19

2013-08-21 Thread Luca Dal Passo
Dear all,

 I have bought an HP 5345A. It’s ok and I’m very glad. On the rear
panel it is wrote OPTION C19 (a little bit strange!) and there are
two additional BNC installed on the little panel normally used to
place the HPIB connector when present.

These 2 BNCs are named REF OUT and REF IN and there is a jumper cable
that connects the output to the input.

It seems to be a modification made by some user (very strange: I can’t
understand why to place an extra auxiliary bypass for the 10 MHz
reference).

Do you have an idea about this strange modification and about the
strange option C19? Could it be a custom option? Could the option C19
and the 2 BNC for the reference be related?

Thanks

Bye

Luca – IW2LJE – Milano – Italy
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Re: [time-nuts] Wawecrest DTS-2077 with TimeLab: was: Wavecrest DTS-2077 Teardown

2013-08-21 Thread Adrian
To be more precise, I have a working DTS-2077 and tried it a few times 
with TimeLab.
TimeLab was always running fine for a few seconds but then it stopped 
and displayed a timeout error.

So, what's wrong?

Adrian

Adrian schrieb:

Ed,

thanks for posting!

I'm still looking for a MUX board for my faulty 2077.

Is there anyone using a DTS-207x with TimeLab?

Adrian


Ed Palmer schrieb:

FYI, I did a teardown on my Wavecrest DTS-2077.  It's posted here:

http://www.eevblog.com/forum/testgear/wavecrest-dts-2077-teardown

Ed

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[time-nuts] HP 5061A or B top cover

2013-08-21 Thread cdelect
Hi,

Anyone have top and bottom covers from  a junked HP 5061A or B (also
5065A)???

I have LOTS of 5061 parts for a swap or can pay a reasonable amount.

Thanks!

Corby Dawson

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Re: [time-nuts] strange hp 5345A option C19

2013-08-21 Thread GandalfG8
Hi Luca
 
There are other items of HP equipment fitted with Ref Out  and Ref In 
terminals joined by an external link, with the intention that  the link is 
removed to connect an external standard to the Ref In terminal,  but in a 
normal 
5345A the external reference is used to phase  lock the internal oscillator 
which means that the unit can't work from an  external reference if the 
internal 10MHz oscillator has been  removed.
 
However, I found some time ago that it is possible, just by fitting a  
single link internally, to drive the counter via an external reference even if  
the internal standard has been removed so I'm guessing that the internal  
standard on this one might have been removed at some time and a previous  
owner has fitted a non original internal standard with a similar provision  to 
bypass the normal arrangement.
 
It should be fairly easy to check just by looking to see if the  original 
HP oscillator is still fitted or whether a different one has been  added.
 
Whether or not this relates to the Option C19 I don't know.
 
Regards
 
Nigel
GM8PZR
 
 
In a message dated 21/08/2013 17:00:21 GMT Daylight Time, iw2...@gmail.com  
writes:

Dear  all,

I have bought an HP 5345A. It’s ok and I’m  very glad. On the rear
panel it is wrote OPTION C19 (a little bit  strange!) and there are
two additional BNC installed on the little panel  normally used to
place the HPIB connector when present.

These 2 BNCs  are named REF OUT and REF IN and there is a jumper cable
that connects the  output to the input.

It seems to be a modification made by some user  (very strange: I can’t
understand why to place an extra auxiliary bypass  for the 10 MHz
reference).

Do you have an idea about this strange  modification and about the
strange option C19? Could it be a custom option?  Could the option C19
and the 2 BNC for the reference be  related?

Thanks

Bye

Luca – IW2LJE – Milano –  Italy
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Re: [time-nuts] Warped back to 1993

2013-08-21 Thread Tammy A Wisdom
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

It looks like it affects truetime XL-DC's I just noticed it at my
house as well :(

On 8/11/13 07:09:40, Magnus Danielson wrote:
 If Furuno can supply the FW to update with, we would be more than
 happy.
 
 A slight alteration of the code would suffice...
 
 if (week  729) week += 2048; else week += 1024;
 
 Which would keep them floating for another 1024 weeks. If they then
 let us know where the two constats is located so we could modify it
 again ourselves we be very happy.
 
 Cheers, Magnus
 
 On 08/11/2013 01:29 PM, Azelio Boriani wrote:
 OK, good, found the bug. Now, iwe wish it were possible to
 download the firmware, make the correction and then upload...
 
 On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson 
 mag...@rubidium.dyndns.org wrote:
 On 08/11/2013 05:18 AM, Mark C. Stephens wrote:
 Okay this is what worked for me:
 
 1. Removed power and antenna. 2. apply power with no
 antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna
 back in.
 
 For some reason if I used the correct date, the Z3815A warped
 back to 1993.
 
 But I am curious why did this happen today?
 GPS weeks begin on sundays. Today is first day of week 1753:
 
 http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11
 
 Going back 1024 days gives you week 729 day 0, which occurs on
 1993 12 26: 
 http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26
 
 A simple way to compensate for the lack of bits is to assume
 wrapping occurs, so week numbers lower than som value actually
 lacks 1024 weeks. A trivial code like this fixes this:
 
 if (week  729) week += 1024;
 
 Brilliant until you reach week 1753.
 
 I've seen this happen at 500 and 512.
 
 Cheers, Magnus
 
 
 --marki
 
 -Original Message- From: time-nuts-boun...@febo.com
 [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C.
 Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion
 of precise time and frequency measurement Subject: Re:
 [time-nuts] Warped back to 1993
 
 Hal, I can't get it to take, I keep getting E-350 and the
 time does not change. Did you unplug the antenna or anything
 while you changed date?
 
 
 
 
 
 -Original Message- From: time-nuts-boun...@febo.com
 [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray 
 Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of
 precise time and frequency measurement Subject: Re:
 [time-nuts] Warped back to 1993
 
 
 ma...@non-stop.com.au said:
 A Z3805A, a Z3815A and 58534A integrated timing antenna all
 think it's 26 Dec 1993. What happened?!
 ___
 Is that off by 1024 weeks?  (Looks close, but I haven't
 checked the details.)
 
 There is a week field in the GPS data stream.  It's only 10
 bits.
 
 I had that problem on a Z3801A.  It did the right thing after
 I told it the date. :GPS:INIT:DATE 2011,12,26
 
 
 
 ___ time-nuts
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Re: [time-nuts] Warped back to 1993

2013-08-21 Thread Russell Rezaian

This seems to impact some, but not all, XL-DC units.

At least one of mine was impacted, some of the others were not.  I think 
it depends on firmware version.


If you check and set the f68 Set Year option this will probably let 
you get things back to displaying the correct date.


At least it worked for the one XL-DC I have which I noted having year 
roll-over issues earlier...

--
Russell


Tammy A Wisdom wrote:

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

It looks like it affects truetime XL-DC's I just noticed it at my
house as well :(



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Re: [time-nuts] Wavecrest DTS-2077 Teardown

2013-08-21 Thread Ed Palmer
Since you're looking for rise times in the low or sub nanosecond range, 
why wouldn't you include any logic gates where such rise times are 
inherent?  I was thinking of maybe a chain of faster and faster logic 
gates.  For example, Potato Semiconductor - no, I'm not making that up - 
PO74G04A has a risetime of  1 ns and, if you can keep the load 
capacitance low enough, a maximum input frequency of  1 GHz.


Always trying to learn

Ed

On 8/20/2013 11:28 PM, Bruce Griffiths wrote:
The same analysis applies however one would probably use something 
like cascaded longtailed pairs with well defined gain (series emitter 
feedback) and the low pass filter cap connected between the collectors 
rather than opamps.


Bruce

Ed Palmer wrote:
Does anyone know if this situation would benefit from doing something 
similar to a 'Collins Hard Limiter' i.e. instead of squaring the 
signal in one stage, use maybe two or three cascaded stages with 
increasing bandwidths? Normally, Collins limiters are used with beat 
frequencies of less than 1 KHz, but maybe there's value in doing at 
typical time-nuts frequencies.


Any thoughts?

Ed


On 8/20/2013 10:02 PM, Said Jackson wrote:

Hi Ed,

For anything up to about 150MHz try the NC74SZ04 types from National 
if you can find them NOS. they stopped making these years ago.. 
Fairchild is ok too but not as fast from what I have seen.


Forgot I wrote about it in 2009. Oh boy -age kicking in.

Bye,
Said

Sent From iPhone

On Aug 20, 2013, at 20:17, Ed Palmer ed_pal...@sasktel.net wrote:


Hi Said,

Yes, I saw your message from 2009 where you warned about the sine 
waves.  That's why I was watching for it.  Thanks for the warning.  
I also realized that a DC Block and a 10 db attenuator makes a very 
nice TTL or CMOS to Wavecrest converter for anything except 1 PPS 
which would need about 15 db.  I tried an old circuit that uses an 
MC10116 ecl line receiver - it's actually a dead Racal Dana 1992 
counter where I'm using the processing on the external reference 
input to square up the signal.  It gives me a slew rate equivalent 
to about a 50 MHz sine wave.  It helped a lot, but not enough.  
I'll try a 74AC04 and a BRS2G Differential Line Receiver (risetime 
 3ns, 400Mbps throughput).  Both are in my junkbox.


Ed


On 8/20/2013 8:12 PM, Said Jackson wrote:

Guys,

The dts needs to be driven by square waves, driving them with sine 
waves gives jitter values that are displayed significantly too 
high due to trigger noise.


Holzworth makes a small sine wave to square wave converter that 
can drive 50 ohms. Use a DC block and an attenuator on the cmos 
output to avoid damaging the dts inputs. You can make your own 
converter using a single fast cmos gate, resistor, and blocking 
cap. By using hand-selected gates I was able to achieve less 
jitter with that circuit than what the Holzworth box was able to 
achieve.


Doing that conversion can bring down the measured rms jitter on a 
very good 10MHz sine wave source from 10ps+ to less than 2ps - 
basically at or below the noise floor of the dts.. Once you run at 
the units' noise floor, you know your source is quite good..


Bye,
Said

Sent From iPhone

On Aug 20, 2013, at 18:51, Ed Palmer ed_pal...@sasktel.net wrote:


Adrian,

I used Timelab to assess the reaction of the DTS-2077 to 
different sine wave inputs.  The differences in the noise floor 
are surprising.  The attached picture was made by taking the 
output of an HP 8647A Synthesized Generator through a splitter, 
and then through different lengths of cables to the inputs of the 
DTS-2077.  The combination of splitter and cable loss meant I 
couldn't get +7 dbm @ 1 GHz.  If I could have, the 1 GHz line 
might have been lower than it was.


Ed


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[time-nuts] NITZ Timestamps

2013-08-21 Thread Tom Harris
Here's a general question about the NITZ timestamp that is sent by the
phone tower when your mobile connects to it. Why are they so far off from
the actual time? I have seen offsets up to 15 seconds behind, mind you this
was from a tower in the bush, city towers are usually only 2 secs behind.

Tom Harris celephi...@gmail.com
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Re: [time-nuts] Wavecrest DTS-2077 Teardown

2013-08-21 Thread Magnus Danielson
On 08/21/2013 03:51 AM, Ed Palmer wrote:
 Adrian,

 I used Timelab to assess the reaction of the DTS-2077 to different
 sine wave inputs.  The differences in the noise floor are surprising. 
 The attached picture was made by taking the output of an HP 8647A
 Synthesized Generator through a splitter, and then through different
 lengths of cables to the inputs of the DTS-2077.  The combination of
 splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz.  If I
 could have, the 1 GHz line might have been lower than it was.
This is not very surprising. As you increase frequency, the slew-rate
changes, and as slewrate increases, it convert noise to jitter to a
lesser degree. Formula for slew-rate:

S = A*2*pi*f

where A is the amplitude and f is the frequency

Formula for jitter

T = e_n / S

where e_n is the noise RMS amplitude, S the slew-rate and T the timing
jitter RMS.

As you get closer to the instruments internal jitter, which forms a
floor, the increased slew-rate does not improve as quickly as you would
think.

Cheers,
Magnus
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Re: [time-nuts] Wavecrest DTS-2077 Teardown

2013-08-21 Thread Magnus Danielson
On 08/21/2013 06:46 AM, Ed Palmer wrote:
 Does anyone know if this situation would benefit from doing something
 similar to a 'Collins Hard Limiter' i.e. instead of squaring the
 signal in one stage, use maybe two or three cascaded stages with
 increasing bandwidths? Normally, Collins limiters are used with beat
 frequencies of less than 1 KHz, but maybe there's value in doing at
 typical time-nuts frequencies.

 Any thoughts?
The input stage of the TADD-2 is a good example, with direct inspiration
from Wenzel it amplifies the signal up. I then use the result to drive a
spare output and there I get much less jitter than the sine 5 MHz alone.

So, the application is low-jitter signal.

Cheers,
Magnus
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Re: [time-nuts] Wavecrest DTS-2077 Teardown

2013-08-21 Thread Ed Palmer

On 8/21/2013 5:52 PM, Magnus Danielson wrote:

On 08/21/2013 03:51 AM, Ed Palmer wrote:

Adrian,

I used Timelab to assess the reaction of the DTS-2077 to different
sine wave inputs.  The differences in the noise floor are surprising.
The attached picture was made by taking the output of an HP 8647A
Synthesized Generator through a splitter, and then through different
lengths of cables to the inputs of the DTS-2077.  The combination of
splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz.  If I
could have, the 1 GHz line might have been lower than it was.

This is not very surprising. As you increase frequency, the slew-rate
changes, and as slewrate increases, it convert noise to jitter to a
lesser degree. Formula for slew-rate:

S = A*2*pi*f

where A is the amplitude and f is the frequency

Formula for jitter

T = e_n / S

where e_n is the noise RMS amplitude, S the slew-rate and T the timing
jitter RMS.

As you get closer to the instruments internal jitter, which forms a
floor, the increased slew-rate does not improve as quickly as you would
think.

Cheers,
Magnus


Yes, I realize all that.  Since I couldn't vary the slew rate of a 
pulse, I used sine waves to 'stand in' for varying slew rates to find 
the value that didn't degrade the results.  5 or 10 MHz is a high enough 
frequency that most equipment won't have a problem with it.  But the DTS 
has such a high level of performance that you need to pay special 
attention to the quality of the input signal.


It would have been nice if Wavecrest had at least mentioned it in the 
manual as something to be considered.  Not doing so can result in misuse 
by the operator that makes their equipment look bad.  I had to think 
about the poor results I was seeing.  At first I wondered if my unit was 
defective.  I haven't read through all their app notes so there could be 
something buried in there.  I know that other vendors do discuss this 
topic in either manuals or app notes related to their counters.  HP App 
Note 200 is a good example of this.  But it's worth noting that in a 
table of Trigger Error vs. Slew Rate, the lowest trigger error listed is 
10ns - not even remotely close to the performance level of the DTS even 
though the copyright date is similar to the DTS's production date.


We tend to fall into a rut when it's never been a problem before. 
Equipment vendors need to warn us when their equipment makes our 
previous assumptions invalid.


Ed

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Re: [time-nuts] NITZ Timestamps

2013-08-21 Thread Christopher Quarksnow
Maybe the 15 second offset was to compensate for the old Android bug that
derived time from GPS rather than UTC ; Sprint told me at that time they
drove most towers with Stratum 2 ref. and only my Android phones exhibited
the issue. The other ones were no more than 0.1 sec off.


On Wed, Aug 21, 2013 at 6:59 PM, Tom Harris celephi...@gmail.com wrote:

 Here's a general question about the NITZ timestamp that is sent by the
 phone tower when your mobile connects to it. Why are they so far off from
 the actual time? I have seen offsets up to 15 seconds behind, mind you this
 was from a tower in the bush, city towers are usually only 2 secs behind.

 Tom Harris celephi...@gmail.com
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Re: [time-nuts] Wawecrest DTS-2077 with TimeLab: was: Wavecrest DTS-2077 Teardown

2013-08-21 Thread John Miles
What GPIB adapter are you using?  Does the 'Monitor' feature also time out,
or just the acquisition itself?

-- john, KE5FX
Miles Design LLC

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
 Behalf Of Adrian
 Sent: Wednesday, August 21, 2013 9:26 AM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Wawecrest DTS-2077 with TimeLab: was: Wavecrest
 DTS-2077 Teardown
 
 To be more precise, I have a working DTS-2077 and tried it a few times
 with TimeLab.
 TimeLab was always running fine for a few seconds but then it stopped
 and displayed a timeout error.
 So, what's wrong?
 
 Adrian

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