Re: [time-nuts] MV89A / MTI-260 / HP10811 carrier board

2016-02-27 Thread jimlux
On 2/27/16 10:16 AM, Gerhard Hoffmann wrote: Am 27.02.2016 um 16:15 schrieb Bob Camp: Hi You will run into the same problem on the Altera side. Their “super suite” is called Quartus and the latest free version only supports the newer parts. Once you get a few generations back, you need to downl

Re: [time-nuts] GPS Outage..

2016-02-27 Thread jimlux
On 2/26/16 11:34 PM, Hal Murray wrote: How many of them came from E-911 stations? E-911 triangulation done on cell towers … I was thinking of the stations where they have the dispatchers who answer the calls and pass the info on to the right people. I think they need good timing on the reco

Re: [time-nuts] GPS Outage

2016-02-27 Thread jimlux
On 2/26/16 12:39 PM, Hal Murray wrote: martin.burni...@burnicki.net said: Strange that at least 3 independant firmware trees/development teams should chose the same magic wk860. I don't find it strange. If the next firmware version is based on the previous version and none of the developers

Re: [time-nuts] GPS Outage

2016-02-26 Thread jimlux
On 2/26/16 3:34 AM, Björn wrote: "The product will not report the correct extended GPS week number after the Feb,13th 2016. After the rollover to week #860, the thunderbolt will not make position for 2 hours, because the Ephemeris data on the GPS receiver being consider incorrect. The module wi

Re: [time-nuts] Measurements - Phase vs TDEV vs ADEV/MDEV

2016-02-21 Thread jimlux
On 2/20/16 10:22 AM, Attila Kinali wrote: Moin, Looking at the phase data, you can see that jitter of the pulses of two nodes is <+/-170ps, with the average being pretty much in a window that is samler than +/-70ps. For the other *DEV plots, I also added measruements of the Teensy 3.1 oscilla

Re: [time-nuts] moon bounce for synchronization

2016-01-30 Thread jimlux
On 1/30/16 4:27 PM, Hal Murray wrote: eb4...@gmail.com said: Back to the Control Room you contact the transmitting station (I think it was DSS12) by voice to insure that they have the station manned and transmitting, and began to operate the "thing". The transmission were specific for each rec

Re: [time-nuts] moon bounce for synchronization

2016-01-30 Thread jimlux
On 1/30/16 10:43 AM, Jeremy Nichols wrote: Ooh! Ooh! Not only a 5245 with a 5265 voltmeter plug-in but a 5360 Computing Pig! Great picture, thanks for posting it. Jeremy N6WFO I like how none of the push buttons in the panel below the counters have labels, either on the faceplate or on the bu

[time-nuts] moon bounce for synchronization

2016-01-30 Thread jimlux
This month's historical picture from JPL http://beacon.jpl.nasa.gov/historical-photo-of-the-month This atomic clock was used at the Goldstone Time Standards Laboratory in 1970, to synchronize clocks at Deep Space Network stations around the world. This master clock was accurate to plus or minus

Re: [time-nuts] Fwd: CGSIC: FW: Official Press Release - GPS Ground System Anomaly

2016-01-28 Thread jimlux
On 1/27/16 11:46 PM, Magnus Danielson wrote: Fellow time-nuts, Here is the official statement. Cheers, Magnus I know we're all time-nuts here and not position-nuts. The thing in the statement that was intriguing was about GPS guided munitions. 13.7 microseconds is about 4.5 km. I've not

Re: [time-nuts] low noise multiplication to 100 MHz

2016-01-22 Thread jimlux
On 1/22/16 12:43 PM, Artek Manuals wrote: OK ...coming back to the original post and see if we can nail down ALL the design requirements well, I wasn't really thinking in terms of formal design requirements.. (I get more than enough of that at work) I was more looking for potential circuit

Re: [time-nuts] low noise multiplication to 100 MHz

2016-01-22 Thread jimlux
On 1/22/16 2:15 AM, REEVES Paul wrote: Why not use something like an HP5254B/C ? They give out 50MHz harmonics up to the low Ghz region, all filtered by a nice high-Q tuneable cavity. All to typical HP build quality. Of course, they have an amount of 'not needed' circuitry and are just a bit

Re: [time-nuts] low noise multiplication to 100 MHz

2016-01-21 Thread jimlux
On 1/21/16 9:26 AM, Richard (Rick) Karlquist wrote: It is interesting that the HP8662A multiplies 10 MHz to 640 MHz, in steps of 2X. But there is a crystal filter at 80 MHz to clean up the wideband noise of the 10811. In the 11729, they filter the 640 MHz from the 8662 with a SAW filter, again

Re: [time-nuts] low noise multiplication to 100 MHz

2016-01-21 Thread jimlux
width is, the noise I'm concerned about is probably inside the loop and will be driven by my reference. I'll take a look at the part. Pete. On 1/21/2016 9:43 AM, jimlux wrote: My tiny 100 MHz low noise OCXOs are unexpectedly delayed at the mfr, and I'm looking at alternati

[time-nuts] low noise multiplication to 100 MHz

2016-01-21 Thread jimlux
My tiny 100 MHz low noise OCXOs are unexpectedly delayed at the mfr, and I'm looking at alternative schemes. One is to get 10 or 20 MHz OCXOs (typically in stock) and multiply them up. I've got the Wenzel ap notes on 2diode and using HCMOS (and I've used the packaged Wenzel multipliers), and I t

Re: [time-nuts] Generating a solid PPS from 10Mhz source

2016-01-19 Thread jimlux
On 1/18/16 4:19 PM, Bob Camp wrote: Hi Some time - check out what a “60 Hz” incandescent bulb looks like when hooked to 20 Hz …. flicker flicker flicker … I suspect they optimize the thermal mass of the filament to reduce the flicker at 50/60 Hz. They optimize that to a tiny fraction of a gn

Re: [time-nuts] New Member + Basic Questions

2016-01-17 Thread jimlux
On 1/16/16 4:29 PM, Nathan Johnson wrote: Right now I'm mostly aligning IF stages of boat anchor rigs, An inexpensive eval board with a synthesizer chip might work for this, like the Si570. Aligning the IF doesn't require great phase noise performance. this is probably a <$50 solution. Pai

Re: [time-nuts] Generating a solid PPS from 10Mhz source

2016-01-16 Thread jimlux
On 1/16/16 10:07 AM, Poul-Henning Kamp wrote: In message <20160116080037.13903406...@ip-64-139-1-69.sjc.megapath.net>, Hal Murray writes: kb...@n1k.org said: The astonishing part of this “new world” is that a very complex chip that is made in high volume is cheaper than a handful of

[time-nuts] beaglebone black, debian, NTP client

2015-12-31 Thread jimlux
Has anyone fooled with using NTP on a beaglebone black running Debian (the beagleboard.org image)? I assume it's just a matter of turning on ntpd (which I'm not sure is even installed) and/or running ntpdate (I'm not looking for super accuracy.. it's for a sprinkler timer)

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-20 Thread jimlux
On 3/19/11 10:41 PM, Bruce Griffiths wrote: Bruce Griffiths wrote: jimlux wrote: A 10-12m diameter dish is probably close to the minimum feasible aperture. A 4m dish can be made to work in conjunction with a mauch larger dish (eg 30m). The original speculation was for measuring the small

Re: [time-nuts] BYMLBI (Back Yard Medium LBI)

2011-03-18 Thread jimlux
On 3/18/11 9:20 PM, li...@lazygranch.com wrote: http://www.astronomycast.com Episode 211 was a good primer on celestial navigation. It covers time piece construction. Building your own backyard continental drift hardware would be high on the coolness scale. good gps measurements processed

Re: [time-nuts] BYMLBI (Back Yard Medium LBI)

2011-03-18 Thread jimlux
That's an interesting idea, but I think all the orbit data for GPS satellites is Earth relative rather than star relative. I wonder if the group that drives the GPS satellites even knows their location relative to the stars. I'll bet not. I'll bet they do. Lots of earth orbiting satellites u

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-18 Thread jimlux
A 10-12m diameter dish is probably close to the minimum feasible aperture. A 4m dish can be made to work in conjunction with a mauch larger dish (eg 30m). The original speculation was for measuring the small change in earth rotation rate, for which some sort of interferometric measurement o

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-18 Thread jimlux
On 3/17/11 12:30 PM, Chris Albertson wrote: On Wed, Mar 16, 2011 at 11:00 PM, jimlux wrote: Synchronizing the several receivers that are spread aroud is not really even required. Many years ago astronomers would mail magnetic tapes and the data would be combined days after the observations

Re: [time-nuts] Thunderbolt setup

2011-03-16 Thread jimlux
On 3/16/11 6:55 PM, Bob Camp wrote: Hi Every place I have lived here in the US wants you to put a simple ground block on the antenna lead. It's not much of an arrestor compared to the "real thing". Since the auction sites will sell you the right part for less than $20 (at least they used to) t

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-16 Thread jimlux
On 3/16/11 11:31 AM, Chris Albertson wrote: On Wed, Mar 16, 2011 at 1:14 AM, Hal Murray wrote: Your pointing accuracy is Y/X, or something close to that. That describes perfectly when radio can beat optics. The angular resolution of the system is the aperture size over the wavelength. So y

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-16 Thread jimlux
On 3/15/11 11:08 PM, Bruce Griffiths wrote: jimlux wrote: On 3/15/11 9:36 PM, Hal Murray wrote: If I were doing this in my backyard on a budget I'd mount a small telescope nearly straight up so that a bright star would pass through the field on several nights. I'd measure the li

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-15 Thread jimlux
On 3/15/11 9:36 PM, Hal Murray wrote: If I were doing this in my backyard on a budget I'd mount a small telescope nearly straight up so that a bright star would pass through the field on several nights. I'd measure the light of the star through a slit and time the peak of the light each night.

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-15 Thread jimlux
On 3/15/11 6:20 AM, jimlux wrote: On 3/15/11 1:49 AM, Chris H wrote: I hear in the Media that the earth quake sped the rotation of the earth up.. Can anyone confirm this? No.. the magnitude of the change is parts in 1E11 or thereabouts. Regular old tidal drag slowing is bigger, and that&#

Re: [time-nuts] Result of Earth Quake speeds up earth?

2011-03-15 Thread jimlux
On 3/15/11 1:49 AM, Chris H wrote: Hello, Firstly may I just say, my thoughts are with members of this list who are in Japan. Just a bit of an odd question... I hear in the Media that the earth quake sped the rotation of the earth up.. Can anyone confirm this? Yes, the media reported it. Yes,

Re: [time-nuts] Spacecraft Timekeeping

2011-03-10 Thread jimlux
It is more a matter about that the involved technology could be ITAR classified or with other export restrictions. Ask Hughes and Boeing about the fine for export control violations in Intelsat 708 :) http://en.wikipedia.org/wiki/Intelsat_708 I think most people who work with rockets with guid

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/9/11 5:43 PM, Sanjeev Gupta wrote: On Wed, Mar 9, 2011 at 22:09, jimlux wrote: OTOH, if you're building a rocket that's big enough to need something like this, you can likely get the needed export licenses, or at least, comply with the export control laws. Wait, he _is_ exp

Re: [time-nuts] NTP IRIG config help

2011-03-09 Thread jimlux
On 3/9/11 11:40 AM, Jim Kusznir wrote: Thanks for the info! I was adjusting the levels with alsamixer, which I suspect is a digital mixer. I hadn't thought of the potential issues there. I was using the onboard sound, but I also have a "higher quality" Soundblaster sound card. Do some of thes

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/9/11 10:58 AM, Kevin Watson wrote: Hi Magnus, As I said in an earlier message, this is an experiment that I want to run and would rather not touch mission and safety-critical GNC components, like our navigation GPS receivers. Mass is not an issue. -Kevin So this makes it pretty simple..

Re: [time-nuts] GPS Usage

2011-03-09 Thread jimlux
Lots of people use GPS for timing because it's cheaper or more convenient in a budgetary sens than alternate approaches. Here at JPL, it's easier, in general, for me to put a GPS timing receiver and GPSDO in a lab than it is to try and run cables from the "house sources". The latter require

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/8/11 11:05 PM, Magnus Danielson wrote: On 03/09/2011 06:08 AM, Kevin Watson wrote: Hi All. Thanks for responding. There are quite a few GPS receivers that will work outside of the usual commercial-grade GPS limitations, but I'm not too sure I need such a receiver. As my application is to ju

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/8/11 9:08 PM, Kevin Watson wrote: Hi All. Thanks for responding. There are quite a few GPS receivers that will work outside of the usual commercial-grade GPS limitations, but I'm not too sure I need such a receiver. As my application is to just accuratly time-tag messages for a data recorder

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/8/11 1:45 PM, Magnus Danielson wrote: Kevin, On 03/08/2011 06:57 PM, Kevin Watson wrote: Hi Jim, Do you, or anyone else, have a recomendation for the GPSDO? Jackson Labs' (http://jackson-labs.com/) DROR seems like it might work, but I wonder if there might be better alternatives. Firs

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/8/11 11:41 AM, Chris Albertson wrote: On Tue, Mar 8, 2011 at 9:57 AM, Kevin Watson wrote: Hi Jim, As part of my research into keeping time on rockets and spacecraft, I joined this list to see what I could learn from the masters. Of course I'm a knuckle-head for not assuming that you'd be

Re: [time-nuts] Spacecraft Timekeeping

2011-03-09 Thread jimlux
On 3/8/11 9:57 AM, Kevin Watson wrote: Hi Jim, As part of my research into keeping time on rockets and spacecraft, I joined this list to see what I could learn from the masters. Of course I'm a knuckle-head for not assuming that you'd be one of the resident masters . Anyway, as my accuracy needs

Re: [time-nuts] GPS Filter

2011-03-08 Thread jimlux
On 3/8/11 4:24 AM, Pieter ten Pierick wrote: Hi, GPS phased arrays aren't new, nor is it necessary to physically steer the antennae within the aray: http://www.navsys.com/papers/0005004.pdf But would such a system help with the LNA overload due to a local transmitter? I would expect that us

Re: [time-nuts] GPS Filter

2011-03-08 Thread jimlux
On 3/7/11 10:27 PM, Chris Albertson wrote: On Mon, Mar 7, 2011 at 7:34 PM, Bob Camp wrote: Hi Since you are after timing off of the sat's, having antennas that move, either physically or electrically seems like a problem. Any shift in the effective antenna location as you tracked the satelli

Re: [time-nuts] GPS Filter

2011-03-08 Thread jimlux
On 3/7/11 9:37 PM, Tom Van Baak wrote: I think it's simple, at least in the nice/common cases. If the antenna geometry has a point that everything swivels around, consider that to the the location of the antenna. I think that covers the typical alt-az mount: http://en.wikipedia.org/wiki/Altazimut

Re: [time-nuts] latest on the lightsquared 'saga'

2011-03-03 Thread jimlux
On 3/3/11 9:34 AM, Bob Camp wrote: Hi There's obviously major fuel behind this thing. I'm willing to pass up GPS underground. It's GPS out in the open that is my main concern. IF they are going to use this for "last mile" connect to homes it will indeed be everywhere and anywhere. IF that's the

Re: [time-nuts] alkali metals and water

2011-03-02 Thread jimlux
On 3/2/11 8:21 PM, Mike S wrote: At 08:43 AM 3/2/2011, jimlux wrote... You know, elements we love, Rb, Cs... http://www.youtube.com/watch?v=eCk0lYB_8c0 Totally safe for work.. (my daughters turned me on to this video, they saw it in their 8th grade science class) When do we get to hear

[time-nuts] alkali metals and water

2011-03-02 Thread jimlux
You know, elements we love, Rb, Cs... http://www.youtube.com/watch?v=eCk0lYB_8c0 Totally safe for work.. (my daughters turned me on to this video, they saw it in their 8th grade science class) ___ time-nuts mailing list -- time-nuts@febo.com To unsu

Re: [time-nuts] PN sequence generation using GPS

2011-02-26 Thread jimlux
On 2/26/11 5:23 AM, ehydra wrote: If one looks in the spectrum in a very fine granular structure the data transferred by SS will be seen on every single spread-code bit!! All needed is a high-enough S/N and a lot of computing power. On the analog side the receiver must be very strong signal capa

Re: [time-nuts] PN sequence generation using GPS

2011-02-26 Thread jimlux
On 2/26/11 4:58 AM, scmcgr...@gmail.com wrote: Hi Chuck I'd see you on my waterfall display. A flexradio is a wonderful thing. The Icom 7x00'es would also see the energy and display it. Maybe, maybe not. Depends on what other activity there is in the band and what the noise properties are

Re: [time-nuts] Nerd facts - 45 years since Allan variance article

2011-02-25 Thread jimlux
On 2/25/11 1:28 PM, paul swed wrote: seems the first document doesn't work. Any other way to get it? Just tried it, and it worked for me... you could probably find it by googling the title or the document number (NASA SP-80) it's probably also in NTRS (NASA Technical Report Server) alth

Re: [time-nuts] OT: NZ Christchurch member

2011-02-25 Thread jimlux
On 2/25/11 7:55 AM, Poul-Henning Kamp wrote: In message, "Wil liam H. Fite" writes: Me: You're saying that the Richter is a poor predictor of surface disruption? For damage assement you really need a vector-version of richter, vertical does a lot more damage than horizontal on average. Y

Re: [time-nuts] PN sequence generation using GPS

2011-02-25 Thread jimlux
On 2/25/11 7:13 AM, scmcgr...@gmail.com wrote: Speaking as a ham, if this is tried you will have hams complaining and DF'ing the offending signal. Speaking as a ham, and as someone who used to build (and attempt to detect and jam) systems like this for a living.. The odds that a OO would se

Re: [time-nuts] VCXO help

2011-02-25 Thread jimlux
On 2/25/11 3:05 AM, ewkeh...@aol.com wrote: As part of the D/M project the counter uses a 100 MHz VCO with an AD 4001 PLL. To simplify further I would like to consider a very simple VCXO, easily available components, no tuning, any ideas out there. For once phase noise is of no concern. Bert K

Re: [time-nuts] OT: NZ Christchurch member

2011-02-24 Thread jimlux
On 2/24/11 5:23 PM, Bob Bownes wrote: What is the conversion factor for Richter to dBm? :) Bob As a guy with degrees in geology and EE. I really should know this...:) Especially since both are log scales.. The problem is that Richter is log magnitude displacement on a particular kind of se

Re: [time-nuts] Looking for info about first true radio controlled clock

2011-02-23 Thread jimlux
On 2/23/11 5:09 AM, Javier Herrero wrote: El 23/02/2011 05:53, jimlux escribió: CCSDS time codes reference NASA 36 bit.. maybe a reference it's in the back of the CCSDS standard. First CCSDS.301 issue seems to be January 1987, and references (on the 4th issue, Nov 2010) listed at last

Re: [time-nuts] PN sequence generation using GPS

2011-02-23 Thread jimlux
On 2/23/11 4:48 AM, Bob Camp wrote: Hi Hop rates below 1,000 per second are far more common in simple systems than anything faster than that. At VHF, you are looking at a everybody being within one hop of each other. That makes the idea of a GPS based code start fairly reasonable. Bob yes

Re: [time-nuts] Looking for info about first true radio controlled clock

2011-02-22 Thread jimlux
On 2/22/11 12:12 PM, Magnus Danielson wrote: Hi Jim! On 02/22/2011 02:34 PM, jimlux wrote: On 2/21/11 10:12 PM, Michael Lombardi wrote: I'm trying to determine the first product that could automatically decode and display a digital time code. Digital time codes were added to WWV in 196

Re: [time-nuts] Looking for info about first true radio controlled clock

2011-02-22 Thread jimlux
On 2/22/11 9:47 AM, michaelalomba...@comcast.net wrote: Thanks very much for the replies so far. I should have been more clear. I am looking for the first radio controlled clock that received a digital time code from a radio transmitter. Not a telegraphic time code (those date back to around

Re: [time-nuts] Looking for info about first true radio controlled clock

2011-02-22 Thread jimlux
On 2/21/11 10:12 PM, Michael Lombardi wrote: I'm trying to determine the first product that could automatically decode and display a digital time code. Digital time codes were added to WWV in 1960 and WWVB in 1965. This was before they were added to any satellite signals, or before they were

Re: [time-nuts] Rom Expansion for HP5370B

2011-02-21 Thread jimlux
On 2/20/11 8:55 PM, John Seamons wrote: I've been looking at this a bit recently. Pictures here: http://jks.com I *am* impressed... And what a coincidence that phk's name can be adequately done on a 7 segment display (or did he have particularly clever parents?... I can only do one of my chi

Re: [time-nuts] PN sequence generation using GPS

2011-02-17 Thread jimlux
On 2/17/11 2:46 PM, Hal Murray wrote: li...@rtty.us said: The key item here is that the system is going to work via amateur radio here in the US. The FCC only lets you use three very specific PN sequences. The three are called out explicitly in the rules. The requirement that they not be reset

Re: [time-nuts] PN sequence generation using GPS

2011-02-17 Thread jimlux
On 2/17/11 9:30 AM, Bob Camp wrote: Hi System design is always about compromise. If you hop slowly, you "stomp" on each channel pretty hard. You are likely to get noticed when you do. The idea is to stomp so rarely and for so short a time that you aren't noticed. If you hop fast, you need to a

Re: [time-nuts] PN sequence generation using GPS

2011-02-17 Thread jimlux
On 2/17/11 7:22 AM, Joe Leikhim wrote: I am trying to stay within the FCC Part 97 rules. The spreading or hopping will be of a narrowband (25 KHz BW) FM signal. I haven't decided on either the FHSS or DSSS approach. I had thought of a FH approach that exploited time of day to address a frequency

Re: [time-nuts] PN sequence generation using GPS

2011-02-17 Thread jimlux
On 2/17/11 3:42 AM, shali...@gmail.com wrote: Or you try all the possible solutions all at once in parallel in a big FPGA and you have instant synch (at least in the time it takes to recognize you have it) May be impractical for very long, complex sequences... If the sequence is long, then w

Re: [time-nuts] PN sequence generation using GPS

2011-02-16 Thread jimlux
On 2/16/11 5:04 PM, Joe Leikhim wrote: Thanks Bob; Does this mean that the 10 MHz clock needs to be somehow divided to an integer evenly divisible by 127 seconds? Also 8192 seems to be unfeasible as it would take 2.2 hours to initialize sync. No.. your 1pps/sync loads the register with all

Re: [time-nuts] PN sequence generation using GPS

2011-02-16 Thread jimlux
On 2/16/11 4:58 PM, Joe Leikhim wrote: Thanks Hal; Transceivers A and B (C etc) would extract clock and 1 PPS from their own GPS. The idea is to use 1 PPS (or derivative) to reset periodically. Yes the propagation delay A-B would limit the hopping/spreading rate unless some mechanism to correct

Re: [time-nuts] PN sequence generation using GPS

2011-02-16 Thread jimlux
On 2/16/11 1:13 PM, Joe Leikhim wrote: For clarification; I am investigating an experiment using GPS to create a FHSS or DSSS project similar to those of AMRAD and described in the ARRL Spread Spectrum Sourcebook. In those experiments, a specific shift register sequence was used (see below), the

Re: [time-nuts] PN sequence generation using GPS

2011-02-16 Thread jimlux
On 2/16/11 1:13 PM, Joe Leikhim wrote: For clarification; I am investigating an experiment using GPS to create a FHSS or DSSS project similar to those of AMRAD and described in the ARRL Spread Spectrum Sourcebook. In those experiments, a specific shift register sequence was used (see below), the

Re: [time-nuts] Tool Needed to Access my Timer Battery

2011-02-16 Thread jimlux
On 2/15/11 11:10 PM, cook michael wrote: Le 16/02/2011 07:21, Heathkid a écrit : BLING? Really? Seriously? A "watch" is considered "bling" now? Can you build a mechanical watch in your workshop that is as accurate as those manufactured 100 years ago? That's technology! Otherwise, a precision

Re: [time-nuts] Tool Needed to Access my Timer Battery

2011-02-16 Thread jimlux
On 2/15/11 10:21 PM, Heathkid wrote: BLING? For time-nut bling... I suggest updating the cesium wrist watch on tvb's site. Come on folks.. who will be the first to sell a *real* atomic wristwatch (not one of those feeble things that receives a signal from WWVB). Doesn't have to be Cs or

Re: [time-nuts] Why do crystals go bad?

2011-02-14 Thread jimlux
On 2/14/11 7:47 PM, Shawn Tayler wrote: Very interesting Bob Thanks. It brings to mind an annoying issue I run into from time to time. VCXO 12.8 Mhz used as a reference in communications gear. Most of the gear is roughly 10 years old and of similar make, both mobile and portable styles. The

Re: [time-nuts] Why do crystals go bad?

2011-02-13 Thread jimlux
On 2/13/11 8:15 PM, gary wrote: Two authors come to mind regarding crystal oscillators: Eric Vittoz and Marvin Ferking. Eric Vittoz is the more modern of the two. His writings tend towards long term stability of crystal oscillators. Basically, most designs put too much energy into the crystal, wh

Re: [time-nuts] From GPS World - Lightsquared ...

2011-02-09 Thread jimlux
On 2/9/11 5:41 PM, Chris Albertson wrote: On Wed, Feb 9, 2011 at 8:23 PM, Charles P. Steinmetz wrote: From a news release issued by the FCC today: "The FCC Enforcement Bureau today announced new efforts to clamp down on the marketing, sale, and use of illegal cellphone and GPS jamming device

Re: [time-nuts] Calculate spectral content from a series of zero crossing time stamps?

2011-02-09 Thread jimlux
On 2/9/11 2:08 PM, Tijd Dingen wrote: The autocorrelation processing is O(N^2) while the DFT can be done in O(N log N) when using FFT. As usual these can be implemented in reversed order such that first the FFT is done to the phase jitter and auto-correlation can be found using O(N) post-proce

Re: [time-nuts] Calculate spectral content from a series of zero crossing time stamps?

2011-02-09 Thread jimlux
On 2/9/11 3:17 AM, Tijd Dingen wrote: (if you want some ancient FORTRAN IV code for this, I've probably got a listing in a box out in the garage from the 70s) Does this box also happen to contain verilog code for it? I don't think Verilog was even a gleam in the inventors' eyes back in t

Re: [time-nuts] Calculate spectral content from a series of zero crossing time stamps?

2011-02-08 Thread jimlux
On 2/8/11 6:32 AM, Mark Kahrs wrote: The Goertzel algorithm is only useful when you want a few frequences (i.e., it evaluates specific frequencies on the unit circle). For general all purpose slicing and dicing, the FFT is what you want. See the ancient book by Rabiner for the details. The C

Re: [time-nuts] an interesting problem

2011-02-06 Thread jimlux
On 2/6/11 12:37 AM, cook michael wrote: I had a quick look at the IEEE-1355 HIC bus on which spacewire is based and it seems that although the clock is not on the wire, it can be reconstructed as an XOR of the strobe and data. So a passthrough connector sampling those lines (differential) with RS

Re: [time-nuts] Frequency multiplication

2011-02-06 Thread jimlux
On 2/5/11 10:20 PM, Tijd Dingen wrote: You don't feed the ADC from the FPGA if you can avoid it. especially if your ADC clock is a different frequency from the processor clock that's being used for most of the other logic on the FPGA. I'd give a ballpark estimate of 20-30 dB isolation between

Re: [time-nuts] an interesting problem

2011-02-06 Thread jimlux
On 2/5/11 10:14 PM, Hal Murray wrote: I've got a system at work with an internal clock oscillator that I want to get some statistics on, but there's no direct visibility for the oscillator, nor do I have a convenient test point that I can probe. ... Fun problem. Thanks for tossing it out.

Re: [time-nuts] an interesting problem

2011-02-05 Thread jimlux
On 2/5/11 8:11 AM, Magnus Danielson wrote: On 05/02/11 16:25, jimlux wrote: Here's an interesting problem.. I've got a system at work with an internal clock oscillator that I want to get some statistics on, but there's no direct visibility for the oscillator, nor do I have a

Re: [time-nuts] Check out my photos on Facebook

2011-02-05 Thread jimlux
On 2/5/11 8:05 AM, Charles P. Steinmetz wrote: John K1AE wrote: Once you install their small unobtrusive application Yeah, right. If there's anything worse than facebook's privacy practices, it's a service provider that requires you to download a "small unobtrusive application" The sm

Re: [time-nuts] an interesting problem

2011-02-05 Thread jimlux
On 2/5/11 7:30 AM, Poul-Henning Kamp wrote: In message<4d4d6bf6.8070...@earthlink.net>, jimlux writes: First, this isn't that different from the analysis used in the NTP protocol, so you should read that with an open mind. That is what got me started thinking it was doable at all

[time-nuts] an interesting problem

2011-02-05 Thread jimlux
Here's an interesting problem.. I've got a system at work with an internal clock oscillator that I want to get some statistics on, but there's no direct visibility for the oscillator, nor do I have a convenient test point that I can probe. I can divide it down by an arbitrary number to genera

Re: [time-nuts] Frequency multiplication

2011-02-05 Thread jimlux
On 2/5/11 3:54 AM, Magnus Danielson wrote: On 05/02/11 12:13, jimlux wrote: And where in-situ changes in the signal processing are needed (e.g. in a software defined radio), the reprogrammable FPGA is a good fit. But there is a tradeoff.. you might want to give the downstream users/programmers

Re: [time-nuts] Frequency multiplication

2011-02-05 Thread jimlux
On 2/5/11 3:04 AM, Magnus Danielson wrote: On 05/02/11 04:33, jimlux wrote: On 2/4/11 1:18 PM, Magnus Danielson wrote: On 02/02/11 19:47, Hal Murray wrote: Bottom line - there's a lot to look into, and they are unlikely to help you out. There are a lot of FPGAs used in DSP applica

Re: [time-nuts] Frequency multiplication

2011-02-04 Thread jimlux
On 2/4/11 1:18 PM, Magnus Danielson wrote: On 02/02/11 19:47, Hal Murray wrote: Bottom line - there's a lot to look into, and they are unlikely to help you out. There are a lot of FPGAs used in DSP applications where the clock to the front end ADC is critical. So I'd expect there would be so

Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread jimlux
On 2/2/11 7:14 AM, Mike S wrote: At 09:45 AM 2/2/2011, jimlux wrote... what was interesting is that the jamming/fail to get fix was at a closer distance for the consumer receiver than for the FAA approved receiver for aircraft. Maybe it's better signal processing in the (presumably

Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

2011-02-02 Thread jimlux
On 2/2/11 6:31 AM, Mark Spencer wrote: Hopefully timing receivers using elevated gps antennas with band pass filtering (ie. the 58532A or equivalent..) and a good sky view and strong signal levels will be more resistant to out of band interference than a typical consumer grade portable GPS with a

Re: [time-nuts] spur prediction DDS software

2011-01-28 Thread jimlux
On 1/28/11 3:59 AM, Luis Cupido wrote: Jim, Bob, Henry, Brian, Thanks to all. Very good. yeap, I do work on matlab so I think there is plenty now to keep me busy ;-) tks. Luis Cupido ct1dmk. p.s.(what's cooking) I need a relatively narrow tunning range but absolutely free of close in spurs,

Re: [time-nuts] Mass vs BTU Function

2011-01-27 Thread jimlux
On 1/27/11 3:20 PM, Hal Murray wrote: jim...@earthlink.net said: Most metals have a specific heat around .34, where water is 1.0. ( so .34 BTU to raise a pound od aluminum by 1 deg F) Where did you get that? probably misremembering.. Standing in an airport terminal trying to figure out whe

Re: [time-nuts] power spectrum of hard limiter output

2011-01-27 Thread jimlux
On 1/27/11 11:19 AM, ehydra wrote: I found chapter Appendix 7A "Analysis of interference in a hard limiter" There is a half page with a couple of formulas. Not much, not practically oriented. Only idealized hard-limiters. I'm interested in SOFT-limiters! Soft limiters are even more complex to

Re: [time-nuts] spur prediction DDS software

2011-01-27 Thread jimlux
On 1/27/11 5:17 AM, Luis Cupido wrote: Hi, Is there a DDS spur prediction software around ? I mean for an arbitrary DDS design, like I would implement with logic or fpga etc. A code where I can enter nr of bits adc bits etc. here's a good start.. Martin Pechanec's work... http://geociti.es

Re: [time-nuts] spur prediction DDS software

2011-01-27 Thread jimlux
On 1/27/11 5:17 AM, Luis Cupido wrote: Hi, Is there a DDS spur prediction software around ? I mean for an arbitrary DDS design, like I would implement with logic or fpga etc. A code where I can enter nr of bits adc bits etc. (not a thing for a particular analog-devices chip or other dds chip)

Re: [time-nuts] spur prediction DDS software

2011-01-27 Thread jimlux
On 1/27/11 5:17 AM, Luis Cupido wrote: Hi, Is there a DDS spur prediction software around ? Not generically.. There is a dissertation out there with some matlab code. I'll see if I can find a link Most of the time what I do is write a little program in matlab/octave, run a bunch of sampl

Re: [time-nuts] power spectrum of hard limiter output

2011-01-25 Thread jimlux
On 1/25/11 10:47 AM, Magnus Danielson wrote: Jim, On 25/01/11 14:53, jimlux wrote: On 1/24/11 1:19 PM, Magnus Danielson wrote: What are you *really* trying to achieve? 1-bit ADC at the end of a noisy channel? I have a GPS receiver front end (sampler) that normally one tests by running

Re: [time-nuts] power spectrum of hard limiter output

2011-01-25 Thread jimlux
On 1/24/11 1:41 PM, Bob Camp wrote: Hi Most communications systems also have constraints based on signals in adjacent channels. That pretty much forces a solution of "lots of filter before lots of gain". Distributing both gain and filtering across multiple stages gets you into a variety of issue

Re: [time-nuts] power spectrum of hard limiter output

2011-01-25 Thread jimlux
On 1/24/11 1:19 PM, Magnus Danielson wrote: What are you *really* trying to achieve? 1-bit ADC at the end of a noisy channel? I have a GPS receiver front end (sampler) that normally one tests by running GPS signals through it, acquiring and tracking the signals and deriving SNR estimates,

Re: [time-nuts] power spectrum of hard limiter output

2011-01-24 Thread jimlux
On 1/24/11 11:44 AM, Magnus Danielson wrote: On 24/01/11 07:39, Bruce Griffiths wrote: jimlux wrote: On 1/23/11 10:01 PM, Magnus Danielson wrote: Jim, On 24/01/11 02:35, jimlux wrote: I'm looking for a reference that gives the power spectrum of the output of a hard limiter (

Re: [time-nuts] power spectrum of hard limiter output

2011-01-23 Thread jimlux
On 1/23/11 10:01 PM, Magnus Danielson wrote: Jim, On 24/01/11 02:35, jimlux wrote: I'm looking for a reference that gives the power spectrum of the output of a hard limiter (1 bit thresholder) with band limited noise and a single sinusoid. At high SNR, the output of the limiter is basica

Re: [time-nuts] power spectrum of hard limiter output

2011-01-23 Thread jimlux
On 1/23/11 7:34 PM, shali...@gmail.com wrote: Jim, You should be able to model it in Spice and do an FFT on the output. Or in Matlab.. Simulation is easy for this one... I was looking for a paper that looked at it analytically.. I figure it's such a straightforward thing that someone back i

[time-nuts] power spectrum of hard limiter output

2011-01-23 Thread jimlux
I'm looking for a reference that gives the power spectrum of the output of a hard limiter (1 bit thresholder) with band limited noise and a single sinusoid. At high SNR, the output of the limiter is basically a square wave at at the input frequency, but as the SNR decreases, it starts to act l

Re: [time-nuts] Update on prescaler board for HP 53131A-like counters

2011-01-23 Thread jimlux
On 1/23/11 4:27 PM, Samuel DEMEULEMEESTER wrote: Hi timenuts, Here is an update for all of you interested by this project. According to the emails I got, you are a lot ;-) What if both inputs are terminated into a load (e.g. 50 ohms) rather than a short? The input circuit in Fig 18 of t

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