Re: [time-nuts] [TekScopes] Fast Rise/Fall Time Pulser

[Larry McDavid]

Mine arrived today. Alas, it uses a USB B connector instead of a more 
common USB mini or micro; I gotta get a cable.


Mine has the comparator IC marked only, "AJK  BAA." Yes, this is an 
Analog Devices ADCMP572 or ADCMP573 Ultrafast SiGe comparator. I'm not 
sure which output configuration is used yet, but likely is the 572 with 
CML output drivers.


The controller IC is a 18F25K50 PIC with integral USB. Level programming 
software is available on the Leo Bodnar website for download.


The board was supplied with a test result data sheet from a Tektronix 
CSA803A (website picture shows a SD30 40 GHz sampling head used) showing 
the pulser rise time as 38.91 ps and the fall time as 33.20 ps with 
about 950 mv P-P.


It's a lovely looking board; lots of thought went into the layout. I 
can't tell if it is multi-layer. Now for that B cable...


Larry


On 10/10/2017 12:19 PM, Larry McDavid lmcda...@lmceng.com [TekScopes] wrote:

There has been discussion recently about generating fast rise/fall time
pulses by various means. Here is a link to a Leo Bodnar device that will
provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses:

http://www.leobodnar.com/shop/index.php?main_page=product_info=124_id=295

This is built on a small PWB with integral BNC connector, powered by 5
vdc through a USB B connector; a trigger output is provided. Price is US$68.

I've ordered one of these for testing.

Is anyone here using one of these?

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

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--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)


--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Gerhard Hoffmann]

Am 10.10.2017 um 22:25 schrieb Magnus Danielson:

This one, if you read what is written there:

http://www.analog.com/en/products/linear-products/comparators/adcmp572.html#product-overview 





I have used a ADCMP580 comparator on a home etched board

with semi rigid for the outputs. This is what I got from it:


< 
https://www.flickr.com/photos/137684711@N07/33305853110/in/album-72157662535945536/ 
>


I have also experimented with BAT15 Schottky limiters to get less rise 
time at the cost of less amplitude.


That has been replaced by a 54754A differential TDR in the mean time :-)

The scope knows its own risetimes and can calculate them away, at least 
somewhat.


BNC and 40 ps rise time don't go together well.


Cheers, Gerhard






On 10/10/2017 10:20 PM, Bruce Griffiths wrote:

It appears to be merely an ECL comparator;
https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/ 



Bruce
On 11 October 2017 at 09:14 Magnus Danielson 
 wrote:



Hi,

On 10/10/2017 09:42 PM, Brooke Clarke wrote:

Hi Larry:

How does it work.
When I was working with microwave semis it was either a tunnel 
diode or

a Step Recovery Diode.



Looking at the pictures, it seems like the surface mounted chip marked
AJK AAA is the driver-chip that connects through a capacitor over to 
the

centerlead of the BNC output.

Some form of driver, and setup such that amplitude scale can be 
controlled.


Cheers,
Magnus
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Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay

[Christopher Hoover]

Tom,

Please see:

  https://www.novatel.com/assets/Documents/Manuals/om-2128.pdf

  https://www.novatel.com/assets/Documents/Manuals/om-2129.pdf


OEM628 and OEM638 boards can take an external frequency reference
(218/4.10.5), but OEM615 cannot.   I've never tried it.


To get the exact time of the PPS you need to enable the TIME message
(219/3.2.173) with something like (untested):

  LOG TIMEA ONTIME 1



A typical way to use the Novatel solution is to wire signals for the events
of interest -- say a camera shutter or start of frame (SOF) or a LIDAR
start of scan (SOS) -- into the receiver on one of the several event inputs.

With a suitable configuration, the log will contain messages with the
current 6-dof + time solution for the event edges.

If you are also logging the full receiver state, you can post-process the
events into better 6-dof + time solutions.



-- Christopher
73 de AI6KG








On Mon, Oct 9, 2017 at 1:02 PM, Tom Van Baak  wrote:

> Christopher,
>
> Thanks for that additional information. Can you (or Gregory) also comment
> on the external frequency input / output and the 1PPS output of this
> receiver?
>
> A quick look at the om-2128.pdf and om-2129.pdf documents has
> words like "better than 250 ns accuracy" and "50 ns increments" but I
> didn't see mention of 1PPS quantization, sawtooth correction, or other
> words commonly used in GPS timing receiver specifications. I'm guessing
> this product is mostly designed for the PN part of PNT (Positioning,
> Navigation, Timing)?
>
> /tvb
>
> - Original Message -
> From: "Christopher Hoover" 
> To: "Discussion of precise time and frequency measurement" <
> time-nuts@febo.com>
> Sent: Monday, October 09, 2017 12:35 PM
> Subject: Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay
>
>
> >I have quite a bit of experience with Novatel hardware include OEM6, CPT
> > and SPAN.
> >
> > CPT is an IMU made by KVH and relabeled by Novatel.The accelerometers
> > are MEMs and the roll rate sensors are FOGs.   Pretty old design.
> > Performance is decent (but not auto alignment good).
> >
> > http://www.kvh.com/Military-and-Government/Gyros-and-
> Inertial-Systems-and-Compasses/Gyros-and-IMUs-and-INS/IMUs/CG-5100.aspx
> >
> > SPAN is the "solution."SPAN-CPT puts the CPT IMU and the receiver in
> a
> > single box.   You could also get just the CPT in a box.
> >
> > The feature set enabled depends on the software keys that are loaded.
> > Caveat emptor.
> >
> > Dual receiver (even if you have the hardware) and ALIGN feature are extra
> > features.
> >
> > Also worth noting is that the circular connectors used on some of the
> > hardware are pricey.  Some are impossible to assemble without specialty
> > tools.
> >
> > -- Christopher.
> > 73 de AI6KG
> >
> >
> > On Sat, Oct 7, 2017 at 2:36 PM, J. L. Trantham  wrote:
> >
> >> Any idea what they are selling for at this time?
> >>
> >> I see that some sold for the BIN price of $349.99 up until June 20.
> After
> >> that, 'Offer Accepted' occurred up through October 5, with a BIN price
> now
> >> of $649.99, all plus $40 shipping.
> >>
> >> Joe
> >>
> >> -Original Message-
> >> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of
> Gregory
> >> Maxwell
> >> Sent: Saturday, October 07, 2017 2:17 PM
> >> To: Discussion of precise time and frequency measurement
> >> Subject: [time-nuts] Novatel Dual frequency GNSS receivers on ebay
> >>
> >> There is an ebay listing for "Novatel GPS-702-GG with SPAN-CPT Single
> >> Enclosure GNSS/INS Receiver + Cable" with a fairly large number
> available.
> >>
> >> This is a Novatel OEM628 dual frequency receiver (supports GPS, Glonass,
> >> SBAS, apparently including L1C and L2C), plus a three fiber ring gyros
> >> (with bias performance that blows away any mems gyro I've ever used)
> and an
> >> 3-axis mems acceletrometer in an aluminum case, plus a decent dual
> >> frequency antenna.  This is a generation-ish old kit.
> >> The industrial casing conspires to make it look somewhat less modern
> than
> >> it actually is.
> >>
> >> The receivers have external clock input (though not plumbed to the
> outside
> >> of the case) which appears to work though I didn't try much with it yet.
> >> Mine came with 2013-ish firmware but easily upgraded to current (2016)
> >> firmware. There is a windows based firmware update tool which talks to
> it
> >> over serial and is very straight forward (The firmware update
> OEM6631.zip
> >> can be found via google).
> >>
> >> You can communicate with them over serial in ascii, there is extensive
> >> firmware documentation that goes over every command
> >> https://www.novatel.com/assets/Documents/Manuals/om-2129.pdf  some
> of
> >> which are specific to other modules. There is also a separate manual for
> >> the inertial navigation specific features (NovAtel SPAN-CPT Users
> >> manual.pdf)
> >>
> >> The external clock 

Re: [time-nuts] Fast Rise/Fall Time Pulser

[Magnus Danielson]

This one, if you read what is written there:

http://www.analog.com/en/products/linear-products/comparators/adcmp572.html#product-overview

Cheers,
Magnus

On 10/10/2017 10:20 PM, Bruce Griffiths wrote:

It appears to be merely an ECL comparator;
https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/

Bruce

On 11 October 2017 at 09:14 Magnus Danielson  wrote:


Hi,

On 10/10/2017 09:42 PM, Brooke Clarke wrote:

Hi Larry:

How does it work.
When I was working with microwave semis it was either a tunnel diode or
a Step Recovery Diode.



Looking at the pictures, it seems like the surface mounted chip marked
AJK AAA is the driver-chip that connects through a capacitor over to the
centerlead of the BNC output.

Some form of driver, and setup such that amplitude scale can be controlled.

Cheers,
Magnus
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Bruce Griffiths]

It appears to be merely an ECL comparator;
https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/

Bruce
> On 11 October 2017 at 09:14 Magnus Danielson  
> wrote:
> 
> 
> Hi,
> 
> On 10/10/2017 09:42 PM, Brooke Clarke wrote:
> > Hi Larry:
> > 
> > How does it work.
> > When I was working with microwave semis it was either a tunnel diode or 
> > a Step Recovery Diode.
> > 
> 
> Looking at the pictures, it seems like the surface mounted chip marked 
> AJK AAA is the driver-chip that connects through a capacitor over to the 
> centerlead of the BNC output.
> 
> Some form of driver, and setup such that amplitude scale can be controlled.
> 
> Cheers,
> Magnus
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Bob Albert via time-nuts]

I built one, and later saw a simpler one.  Very fast, very simple.  I think my 
total cost was a few cents.
Google TDR DIY pulser.  One from an old magazine (Jim Williams) looks pretty 
good, using collector breakdown of a 2N2369.  The one I made used one IC and a 
few resistors.

Bob
 

On Tuesday, October 10, 2017 1:02 PM, Brooke Clarke  
wrote:
 

 Hi Larry:

How does it work.
When I was working with microwave semis it was either a tunnel diode or a Step 
Recovery Diode.

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 
> There has been discussion recently about generating fast rise/fall time 
> pulses by various means. Here is a link to a 
> Leo Bodnar device that will provide <40 ps rise/fall time, 50% duty cycle, 10 
> MHz pulses:
>
> http://www.leobodnar.com/shop/index.php?main_page=product_info=124_id=295
>
> This is built on a small PWB with integral BNC connector, powered by 5 vdc 
> through a USB B connector; a trigger output 
> is provided. Price is US$68.
>
> I've ordered one of these for testing.
>
> Is anyone here using one of these?
>

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Re: [time-nuts] Fast Rise/Fall Time Pulser

[paul swed]

I looked at the picture and I can see now that the sma is the pulse and the
BNC is the output trigger. Pretty interesting for the cost.
I then did a search on google for fast pulse generation and a analog
devices solution came up that delivers 50ps and actually shorter. I doubt
its one and the same method. But look forward to other comments.
Regards
Paul
WB8TSL

On Tue, Oct 10, 2017 at 3:42 PM, Brooke Clarke  wrote:

> Hi Larry:
>
> How does it work.
> When I was working with microwave semis it was either a tunnel diode or a
> Step Recovery Diode.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
>
>  Original Message 
>
>> There has been discussion recently about generating fast rise/fall time
>> pulses by various means. Here is a link to a Leo Bodnar device that will
>> provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses:
>>
>> http://www.leobodnar.com/shop/index.php?main_page=product_in
>> fo=124_id=295
>>
>> This is built on a small PWB with integral BNC connector, powered by 5
>> vdc through a USB B connector; a trigger output is provided. Price is US$68.
>>
>> I've ordered one of these for testing.
>>
>> Is anyone here using one of these?
>>
>>
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Magnus Danielson]

Hi,

On 10/10/2017 09:42 PM, Brooke Clarke wrote:

Hi Larry:

How does it work.
When I was working with microwave semis it was either a tunnel diode or 
a Step Recovery Diode.




Looking at the pictures, it seems like the surface mounted chip marked 
AJK AAA is the driver-chip that connects through a capacitor over to the 
centerlead of the BNC output.


Some form of driver, and setup such that amplitude scale can be controlled.

Cheers,
Magnus
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Adrian Godwin]

I expected it to be a variant of the Jim Williams avalanche pulse
generator, but one of the photos shows a part marked AJK AAA that appears
to be the active component.

http://www.leobodnar.com/files/40ps-pulser-RevG.jpg


On Tue, Oct 10, 2017 at 8:42 PM, Brooke Clarke  wrote:

> Hi Larry:
>
> How does it work.
> When I was working with microwave semis it was either a tunnel diode or a
> Step Recovery Diode.
>
> --
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
>
>  Original Message 
>
>> There has been discussion recently about generating fast rise/fall time
>> pulses by various means. Here is a link to a Leo Bodnar device that will
>> provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses:
>>
>> http://www.leobodnar.com/shop/index.php?main_page=product_in
>> fo=124_id=295
>>
>> This is built on a small PWB with integral BNC connector, powered by 5
>> vdc through a USB B connector; a trigger output is provided. Price is US$68.
>>
>> I've ordered one of these for testing.
>>
>> Is anyone here using one of these?
>>
>>
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Re: [time-nuts] Fast Rise/Fall Time Pulser

[Brooke Clarke]

Hi Larry:

How does it work.
When I was working with microwave semis it was either a tunnel diode or a Step 
Recovery Diode.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

 Original Message 
There has been discussion recently about generating fast rise/fall time pulses by various means. Here is a link to a 
Leo Bodnar device that will provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses:


http://www.leobodnar.com/shop/index.php?main_page=product_info=124_id=295

This is built on a small PWB with integral BNC connector, powered by 5 vdc through a USB B connector; a trigger output 
is provided. Price is US$68.


I've ordered one of these for testing.

Is anyone here using one of these?



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[time-nuts] Fast Rise/Fall Time Pulser

[Larry McDavid]

There has been discussion recently about generating fast rise/fall time 
pulses by various means. Here is a link to a Leo Bodnar device that will 
provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses:


http://www.leobodnar.com/shop/index.php?main_page=product_info=124_id=295

This is built on a small PWB with integral BNC connector, powered by 5 
vdc through a USB B connector; a trigger output is provided. Price is US$68.


I've ordered one of these for testing.

Is anyone here using one of these?

--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: [time-nuts] precision frequency/time/amplitude reference

[Bob kb8tq]

HI


> On Oct 9, 2017, at 8:49 PM, jimlux  wrote:
> 
> On 10/9/17 8:02 AM, Bob kb8tq wrote:
>> Hi
>> Pick a couple of local broadcast stations and record them. That will give 
>> you a baseline
>> for each of the parameters you are after in real time. They *will* drift.
>> Past that, I’d go with a sweep of each node before installation. That will 
>> give you the
>> frequency response and (to some degree) a guess for noise and spurs.
> 
> The RTL-SDR has only about 2 MHz BW, so you'd have to be lucky to have a 
> broadcast station in the band (and if I'm looking at trying to image Jupiter 
> with an interferometer, at 20.1 MHz, I'm not sure that the SW broadcast bands 
> cover within 2MHz - and you'd be subject to the vagaries of propagation.. low 
> sunspots = low critical frequency = not much skywave propagation for WWV).
> 
> So a local reference would be nice.  Originally, I thought about just 
> radiating a CW tone (perhaps modulated with timecode), but then, I realized 
> I'd also like to calibrate the RF chain in the receiver, so feeding a 
> calibrated pulse that has spurs (hey, a "marker beacon" in old school radios 
> with a analog dial)

Monitor for 55 minutes and calibrate for 5 minutes. Do the calibration in maybe 
10 second segments spread
out over the hour. 

The gotcha with any “radiated” signal is finding a band you can legally 
transmit it in ….. For an array a few feet on a 
side, not a big deal. For something a mile or two across, it begins to be an 
issue. 

Bob


> 
> 
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