Re: [time-nuts] Do I have a defective thunderbolt?
Hi, Both slashes work fine for me! That is an artifact of IE on Windows. According to RFC 1738, URLs use the '/' to separate components of a hierarchy. Because MS-DOS (and therefor Windows...) uses '\' as a path separator, people using Windows will type the wrong separator in an URL. That is then 'fixed' by IE, instead of educating the user that the wrong separator is used... Problem is that people also use this wrong separator in html files, resulting in broken images/links :-( Also result of the difference in path separator between Unix and Windows: At my previous company a Sun workstation running Solaris was used as the main controller for the testbench and product, while a lot of people used Windows on the desktop. Sometimes I found files such as '\home\user\datafiles\bla\testresults.txt' on the machine, using the wrong separator. That PC user of course not understanding why the result file was not in his/her home directory :-) Greetings, Pieter. You've mixed up the backslashes used by Windows with the forward slashes expected on the WEB. Links should be: http://www.decampos.net/LH/LH1.png http://www.decampos.net/LH/LH2.pnghttp://www.decampos.net/LH/LH2.png Bruce Geraldo Lino de Campos wrote: For some reason, the links didn´t include the suffix png. The correct linkas are www.decampos.net\LH\LH1.png www.decampos.net\LH\LH2.png -- Raj, VU2ZAP Bangalore, India. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Slashes
Peter Hal, Thanks for the explanations. I use Firefox, so I guess it's a windows thing and not just IE. I am also familiar with regular expressions although I don't use Unix/Linux. It is useful for open office searches and a few utils that I have collected or programmed over the last few decades. Raj That is an artifact of IE on Windows. According to RFC 1738, URLs use the '/' to separate components of a hierarchy. Because MS-DOS (and therefor Windows...) uses '\' as a path separator, people using Windows will type the wrong separator in an URL. That is then 'fixed' by IE, instead of educating the user that the wrong separator is used... Problem is that people also use this wrong separator in html files, resulting in broken images/links :-( Also result of the difference in path separator between Unix and Windows: At my previous company a Sun workstation running Solaris was used as the main controller for the testbench and product, while a lot of people used Windows on the desktop. Sometimes I found files such as '\home\user\datafiles\bla\testresults.txt' on the machine, using the wrong separator. That PC user of course not understanding why the result file was not in his/her home directory :-) Greetings, Pieter. -- Raj, VU2ZAP Bangalore, India. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] OT: 5372A
Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
Pete, 5u: 50lbs or so. Not sure on the physical dims but can check when I get home. Have fun! That instrument is a pain in the ass to set up. TI on the 5370a: Simple TI on the 5372a: complex setup. Good news is that you have control of everything. Bad news is that you have to specify everything. Norm n3ykf Pete Lancashire p...@petelancashire.com wrote: Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
Pete, 5u: 50lbs or so. Not sure on the physical dims but can check when I get home. Have fun! That instrument is a pain in the ass to set up. TI on the 5370a: Simple TI on the 5372a: complex setup. Good news is that you have control of everything. Bad news is that you have to specify everything. Norm n3ykf Pete Lancashire p...@petelancashire.com wrote: Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
It's so heavy that they wouldn' publish the weight ;) Dimensions and weight are in the specs document 5952-8012. Net 25.5 kg (56 lbs), shipping 36.4 kg (80 lbs). Overall dimensions with feet and front handles: w 425 mm (16.75), h 187 mm (7.35), d 645 mm (25.4). In other words, it's quite a massive piece of equipment. And, it's a hungry beast, too (max power 500 VA as by the specs). Adrian Pete Lancashire schrieb: Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
On 11/19/2010 05:01 PM, Pete Lancashire wrote: Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs From the HP5372A Service Manual (05372-90016) page 1-8 (page 117 in PDF): WARNING: The HHP 5372A WEIGTS 23,2 Kg (51 LBS). The Rack-Slide mount kits adds more. My HP5372A is 51 cm deep, 42,5 cm wide and 19 cm high (4 U + feets). The battery on the processor board usually needs replacement, after that some calibration is needed to get workable function. Not too hard. Done it twice now. Off to grab some gear and hit the road to fellow time-nut 2 h drive away... Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Back slash in URLs
Hi And then sometimes a \ means continued on the next line. Maybe in some files it means count what's after this as a comment. Hauling stuff back and forth between OS's is a pain. If you use a Linux box for timing data collection, and do the processing on a Windows machine - things can get break in a lot of odd ways. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Friday, November 19, 2010 2:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Back slash in URLs Both slashes work fine for me! There are two areas that I know of that lead to horrible confusion between Windows and Unix systems and users. Both involve strange characters in file names. One is \, the other is space. Unix/Linux systems use \ for magic in command line parsers and scripts. That is \* means a literal * rather than all the files in the right context. (So does *.) The other problem is spaces. If you are using a GUI, spaces aren't much of a problem. But if you cut/paste, they don't work unless you are sharp enough to notice the problem and put s around them or some other workaround. It's much simpler to use _ or - rather than space if you have a multi word filename. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
Thanks everyone. The question came up in what I am being charged for shipping From Texas to Oregon, $140 UPS Ground. Not complaining since I got the thing for $53. Hopefully will be FIP. -pete PS Thanks also on the battery issue. Next to get a real service manual. On Fri, Nov 19, 2010 at 8:41 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 11/19/2010 05:01 PM, Pete Lancashire wrote: Looking for what one weighs and its dimensions. Checked two HP catalogs but cant find in the specs From the HP5372A Service Manual (05372-90016) page 1-8 (page 117 in PDF): WARNING: The HHP 5372A WEIGTS 23,2 Kg (51 LBS). The Rack-Slide mount kits adds more. My HP5372A is 51 cm deep, 42,5 cm wide and 19 cm high (4 U + feets). The battery on the processor board usually needs replacement, after that some calibration is needed to get workable function. Not too hard. Done it twice now. Off to grab some gear and hit the road to fellow time-nut 2 h drive away... Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Getting Started in High Precision Timing
Matt, As a follow up just ran across this which is good to get started with : http://www.wriley.com/Examples%20of%201%20PPS%20Clock%20Measuring%20Systems.pdf In fact Mr. Riley has a very good selection of material at : http://www.wriley.com/#papers Stanley - Original Message From: Matt Davis mattdav...@gmail.com To: time-nuts@febo.com Sent: Mon, November 15, 2010 7:31:42 AM Subject: [time-nuts] Getting Started in High Precision Timing Hello all, I have been a software hacker for years but have never really done too much hardware hacking. I have been looking at oxco modules, but the data sheets of various vendors do not really provide me with a good basis as to what such an oscillator would provide me. I assume its just oscillation given the given frequency. Do any of you all have any good links/resources aside from what a basic google would provide, as to how to get the data from the oscillator at a pulse-per-second rate allowing me to do some basic timing. Really, I'm just looking for some first steps in hacking on these high-precision oscillators. Thanks -Matt ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Laser oscillator distance measurement ckt
lstosk...@cox.net wrote: I want to build a simple digital tape measure for the range from near zero to perhaps 10 ft with some remote output. The off the shelf units are accurate to perhaps 1/16 inch, but do not provide continuous outputs. The Bluetooth units seem to require pushing a button for each measurement. The AR4000 uses an open loop oscillator method: Laser on, beam to target, reflected to photodiode (the time delay we want), then detected, amplified to turn off the laser, photodiode (decides) no light and turns the laser on (time to be minimized). Measure the frequency and calculate the distance. The AR4000 has oscillation frequency of about 50 MHz at zero distance (the circuit delay) and about 4 MHz at 50 ft. Easily measured. Circuit looks pretty easy with modern devices. Anyone already have something or ideas for best devices? Thanks, N0UU It doesn't use time of flight, but there are a variety of short range distance measuring schemes that rely on parallax. you have a linear sensor next to the laser, and you basically look for where the spot is. The sensors vary all the way from simple segmented photovoltaic/photoresistive (DC voltage proportional to position of spot on sensor) to linear CCD/CMOS sensors (a fax sensor with 1800 pixels, for instance) to inexpensive CMOS cameras (640 pixels with a suitable lens can give you subpixel resolution by centroiding the spot... perhaps 1 part in 1000/2000 is possible.. out of 120 inches, that would get you in the tenths of an inch, with better resolution close up) These things are available as an off the shelf device for $50, by the way. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Hyperterminal with variable baud rate
Thanks everyone! I ended up using comlog.exe from the Tom's Leapsecond.com website. It's a DOS program. Works great at the 955 baud required! I'll post details of the project soon as others might be interested. It will have a topic line of, Stand-alone Use of the FE 5650A or 5680A DDS board. Corby Dawson Obama Urges Homeowners to Refinance If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.juno.com/TGL3141/4ce6c0b03463144284m04duc ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Getting Started in High Precision Timing
Hi Not to mention the link on the page to Stable-32, which is a very nice piece of software. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Stanley Reynolds Sent: Friday, November 19, 2010 12:21 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Getting Started in High Precision Timing Matt, As a follow up just ran across this which is good to get started with : http://www.wriley.com/Examples%20of%201%20PPS%20Clock%20Measuring%20Systems. pdf In fact Mr. Riley has a very good selection of material at : http://www.wriley.com/#papers Stanley - Original Message From: Matt Davis mattdav...@gmail.com To: time-nuts@febo.com Sent: Mon, November 15, 2010 7:31:42 AM Subject: [time-nuts] Getting Started in High Precision Timing Hello all, I have been a software hacker for years but have never really done too much hardware hacking. I have been looking at oxco modules, but the data sheets of various vendors do not really provide me with a good basis as to what such an oscillator would provide me. I assume its just oscillation given the given frequency. Do any of you all have any good links/resources aside from what a basic google would provide, as to how to get the data from the oscillator at a pulse-per-second rate allowing me to do some basic timing. Really, I'm just looking for some first steps in hacking on these high-precision oscillators. Thanks -Matt ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] DOCXO vs. Rubidium medium-term stability
Greetings, I just discovered this mailing list, this is my first submission. Glad to find a group of folks who are into this kind of stuff! I'm working on an data acquisition application for my company that will require a very stable oscillator. Without going into too many specifics, there will be some reference stations spaced 100's of kilometers apart from each other and 1 mobile station that will be operated in an area where GPS is not available. I need to be able to collect data at all the stations and have the time synchronization be extremely good between the stations, including the one without GPS. For the reference stations it will be sufficient to have the timing of each one driven by a good GPSDO. Clocks will be sync'ed to UTC via the NMEA string and 1pps edge and all of the digital electronics will use the GPSDO 10MHz as their timebase. Periodic re-synchronization to the 1pps edge can be done as needed. The mobile station can be synchronized to GPS initially to synchronize its clock as described above but will then have to rely on a free-running oscillator. The stability of this oscillator will dictate how much drift the mobile station's clock will experience relative to the reference stations. Keeping this drift as low as possible is my goal. I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
Dave, Something is not making sense to me here. As GPS is generally available around the globe and obviously to your reference stations; how is it that the mobile will be able to find an area where the GPS is not available ? As to the mobile, if it is not going to utilize the GPS for a reference, you then need to determine the worst case error you can have over the course of time that the mobile is away from its GPS capability. That factor will dictate the kind of on-board reference you will need. It could be that a very good quality crystal oscillator will suffice. BillWB6BNQ Dave Jabson wrote: Greetings, I just discovered this mailing list, this is my first submission. Glad to find a group of folks who are into this kind of stuff! I'm working on an data acquisition application for my company that will require a very stable oscillator. Without going into too many specifics, there will be some reference stations spaced 100's of kilometers apart from each other and 1 mobile station that will be operated in an area where GPS is not available. I need to be able to collect data at all the stations and have the time synchronization be extremely good between the stations, including the one without GPS. For the reference stations it will be sufficient to have the timing of each one driven by a good GPSDO. Clocks will be sync'ed to UTC via the NMEA string and 1pps edge and all of the digital electronics will use the GPSDO 10MHz as their timebase. Periodic re-synchronization to the 1pps edge can be done as needed. The mobile station can be synchronized to GPS initially to synchronize its clock as described above but will then have to rely on a free-running oscillator. The stability of this oscillator will dictate how much drift the mobile station's clock will experience relative to the reference stations. Keeping this drift as low as possible is my goal. I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
WB6BNQ wrote: Dave, Something is not making sense to me here. As GPS is generally available around the globe and obviously to your reference stations; how is it that the mobile will be able to find an area where the GPS is not available ? If GPS is jammed, you're in a high multipath area, or other reasons... Maybe the reference stations are above water, but your mobile unit is underwater during most of the data collection. Or if you're doing underground surveying.. not necesarily well logging, but say you're doing Electromagnetic surveys, I can think of lots of scenarios needing this.. As to the mobile, if it is not going to utilize the GPS for a reference, you then need to determine the worst case error you can have over the course of time that the mobile is away from its GPS capability. That factor will dictate the kind of on-board reference you will need. It could be that a very good quality crystal oscillator will suffice. Indeed.. if you're looking at times 24hrs, a good OCXO would probably do it. I'm working on an data acquisition application for my company that will require a very stable oscillator. Without going into too many specifics, there will be some reference stations spaced 100's of kilometers apart from each other and 1 mobile station that will be operated in an area where GPS is not available. I need to be able to collect data at all the stations and have the time synchronization be extremely good between the stations, including the one without GPS. For the reference stations it will be sufficient Sufficient meaning you need tens of nanoseconds sort of precision/accuracy? The mobile station can be synchronized to GPS initially to synchronize its clock as described above but will then have to rely on a free-running oscillator. The stability of this oscillator will dictate how much drift the mobile station's clock will experience relative to the reference stations. Keeping this drift as low as possible is my goal. How good does it have to be, and how long will you be out of touch... as low as possible is pretty darn low in this crowd.. Do you need 1 part in 1E13 over a week? Or 1 ppb over a day? (about 100 microseconds/day) Are you recording RF/Acoustic signals and need to be able to form coherent sums? I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Almost certainly... the advantage of an Rb is that you can turn it off, then turn it back on days later, and in a relatively short time, have decent absolute accuracy. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
jab...@quasarfs.com said: The mobile station can be synchronized to GPS initially to synchronize its clock as described above but will then have to rely on a free-running oscillator. The stability of this oscillator will dictate how much drift the mobile station's clock will experience relative to the reference stations. Keeping this drift as low as possible is my goal. Don't get hung up on the D idea. There are many very good single oven OCXOs out there. I think you will be much happier if you figure out how low a drift you need. I'm guessing you don't have a firm number because it interacts with other parts of the system and you are still designing that part. You need some rough numbers for sanity checking your options. Typical GPSDO boxes are good for a few microseconds over 24 hours of holdover. Is that within your ballpark? You can probably do much better than their spec sheet if your temperature is stable. Do you need one for a single experiment, or many for a production run? Do you need to prove it is good-enough from the spec sheets or can you try one in the lab, and run with it if it works? My suggestion would be to get a couple of good OCXOs, put them in the lab next to your Rb, and see how well they work. It's probably worth a few phone calls to see if the vendors have any data on 12 hour holdover. (But check the environmental conditions.) -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
Hi How much warmup time do you have before you go mobile? If the mobile unit can be kept hot before it heads out - the DOCXO wins. If it's a power up and roll in 10 minutes sort of thing, then the Rb is the only way to go. Bob On Nov 19, 2010, at 3:56 PM, Dave Jabson wrote: Greetings, I just discovered this mailing list, this is my first submission. Glad to find a group of folks who are into this kind of stuff! I'm working on an data acquisition application for my company that will require a very stable oscillator. Without going into too many specifics, there will be some reference stations spaced 100's of kilometers apart from each other and 1 mobile station that will be operated in an area where GPS is not available. I need to be able to collect data at all the stations and have the time synchronization be extremely good between the stations, including the one without GPS. For the reference stations it will be sufficient to have the timing of each one driven by a good GPSDO. Clocks will be sync'ed to UTC via the NMEA string and 1pps edge and all of the digital electronics will use the GPSDO 10MHz as their timebase. Periodic re-synchronization to the 1pps edge can be done as needed. The mobile station can be synchronized to GPS initially to synchronize its clock as described above but will then have to rely on a free-running oscillator. The stability of this oscillator will dictate how much drift the mobile station's clock will experience relative to the reference stations. Keeping this drift as low as possible is my goal. I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] OT: 5372A
On 19/11/10 18:13, Pete Lancashire wrote: Thanks everyone. The question came up in what I am being charged for shipping From Texas to Oregon, $140 UPS Ground. Not complaining since I got the thing for $53. Hopefully will be FIP. -pete PS Thanks also on the battery issue. Next to get a real service manual. I've done most of the things I need with what's on the net. Replacement of the battery was trivial. Finding out that it was the root cause was a bit less than obvious. The input sensitivity calibration always goes flat-line, being a huge factor of annoying you, as you would need to trim it up on each power-up. It's done with menues and no service-mode required. Replacing the battery is a matter of finding a 3,6V Lithium battery and do some soldering. Then after power-up do the input calibration and you are all set for the next 20 years or so. It is worth the effort and not hard at all. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Stand-alone Use of the FE 5650A or 5680A DDS board
Hi, Everyone, A couple years ago I used the DDS board out of an FE5680A in a project. Here are some details I discovered about using the board by itself. The project was using the guts of an Efratom FRSC to run the physics package from an HP 5065A. (I called it a 5065A junior!) I needed to replace the fixed .3125Mhz that mixes with the 5Mhz to provide the offset frequency with a .314962Mhz from the DDS. The Efratoms 20Mhz clock provided the DDS clock. I programmed the DDS for .629924Mhz, took the output thru an op-amp a 74HCT14 and a 74HCT74 to give me the TTL .314962Mhz. Once the system was working the two pushbuttons on the DDS board could be used for a fine adjustment. (LSB was approx. 2.5X10-13th) The board can be programmed via RS232 but only if the clock is at the original 50.255Mhz, which equates to 9600 baud. This was not a problem as I only needed to program it once on the bench and then use the C field for fine tuning. My current project uses the same hardware but with a DDS clock frequency of 5Mhz and a final output frequency of 5.7517195 Khz. This to substitute for the built in synthesizer of a Hydrogen Maser for some troubleshooting. This requires a DDS output frequency of 92.027512Khz and replacing the HCT74 with an HCT393. Only 1/2 of the 393 is used for a divide by 16. (this gives an LSB value of approx. 5X10-13th) Also I wanted to be able to vary the frequency via RS232 while installed. This required the terminal program be able to be set to 955 baud. One other bit of info is that at the low clock frequency the two pusbuttons that inc/dec the LSB must be held down until the heartbeat LED on the DDS board transitions from one state to another or the entry will not take! This info will let you use 5 or 10Mhz as the DDS clock frequency and still be able to program it in realtime! (1910 baud for a 10Mhz clock frequency) If anyone is interested I can provide a schematic for the opamp/divider circuits. The DDS board info is widely available on the net. At the frequencies I used I did not have to add the parallel capacitors mentioned by some. Also note the DDS board I used is the one from the 1PPS output units. Hope this is useful! Corby Dawson Moms Asked to Return to School Grant Funding May Be Available to Those That Qualify. http://thirdpartyoffers.juno.com/TGL3141/4ce71bb6f031745232m04duc ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
Hello Dave, as some folks have already mentioned here, the best solution for you will depend on your specific requirements in terms of how much warmup time you have before GPS is gone, and how much drift your solution can handle. The PRS-10 is a good unit, but requires cooling, a large amount of power, only has a single 10MHz and 1PPS output, and it has a somewhat noisy output in terms of phase noise and short-term-stability. It also costs about $1500, is quite large, and does not provide a GPS receiver, nor one especially optimized for timing. You may want to look at the Fury or FireFly-IIA GPSDO units, these are lower cost, include the complete GPS sub-system, achieve performance similar to the PRS-10 after sufficient warmup, are much smaller, lower power, the FireFly-IIA has a built-in isolated distribution amplifier, and don't have an Rb lamp life limitation. Typical Fury DOCXO units can achieve better than 1us drift over 24 hours after they have fully stabilized, which is better than many Rubidium references. If you are looking for drift in the 10us range per day, you will need a double oven SC-cut OCXO. You didn't mention if your application was airborne, in that case you may need a low-g sensitivity oscillator to avoid loss of short term stability and increased phase noise due to aircraft vibration and acceleration. Rubidiums are especially sensitive to airborne vibration such as caused by Turboprops, Rotorcraft, etc. Without having your specifications for the warmup time, thermal changes, and the desired drift, it is difficult to say if a single oven, double oven, Cesium, or Rubidium based unit would work for you. Lastly, unless you are underwater or under-ground, GPS should be available with a modern, good jamming-resistant receiver, and if it is a modern GPSDO will perform as well or better than a modern Rb. bye, Said In a message dated 11/19/2010 14:43:43 Pacific Standard Time, li...@rtty.us writes: I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
Hi Dave, forgot to mention: The PRS-10 also has a limited temperature range only up to +65C, so military applications are a no-go. A good DOCXO will have +75C or even +85C capability. Also, the spec for the PRS-10 is 1.18E-012 per Degree C temperature change, and the units I mentioned before with the DOCXO are available in better than 2E-012 per Degree C over a wider temp range, so are very similar in performance over temperature. bye, Said In a message dated 11/19/2010 18:12:13 Pacific Standard Time, saidj...@aol.com writes: Hello Dave, as some folks have already mentioned here, the best solution for you will depend on your specific requirements in terms of how much warmup time you have before GPS is gone, and how much drift your solution can handle. The PRS-10 is a good unit, but requires cooling, a large amount of power, only has a single 10MHz and 1PPS output, and it has a somewhat noisy output in terms of phase noise and short-term-stability. It also costs about $1500, is quite large, and does not provide a GPS receiver, nor one especially optimized for timing. You may want to look at the Fury or FireFly-IIA GPSDO units, these are lower cost, include the complete GPS sub-system, achieve performance similar to the PRS-10 after sufficient warmup, are much smaller, lower power, the FireFly-IIA has a built-in isolated distribution amplifier, and don't have an Rb lamp life limitation. Typical Fury DOCXO units can achieve better than 1us drift over 24 hours after they have fully stabilized, which is better than many Rubidium references. If you are looking for drift in the 10us range per day, you will need a double oven SC-cut OCXO. You didn't mention if your application was airborne, in that case you may need a low-g sensitivity oscillator to avoid loss of short term stability and increased phase noise due to aircraft vibration and acceleration. Rubidiums are especially sensitive to airborne vibration such as caused by Turboprops, Rotorcraft, etc. Without having your specifications for the warmup time, thermal changes, and the desired drift, it is difficult to say if a single oven, double oven, Cesium, or Rubidium based unit would work for you. Lastly, unless you are underwater or under-ground, GPS should be available with a modern, good jamming-resistant receiver, and if it is a modern GPSDO will perform as well or better than a modern Rb. bye, Said In a message dated 11/19/2010 14:43:43 Pacific Standard Time, li...@rtty.us writes: I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
Hi If high temperature is an issue, keeping the Rb cool will be a major chore. The OCXO will be far more happy at 75 than the Rb will be at 65. Depending on just how mobile we're talking about, the OCXO may have some issues with 2G tip / acceleration. There's a lot to consider in a setup like this and without a bit more data we're going to head off into crazy land pretty fast. Bob On Nov 19, 2010, at 9:36 PM, saidj...@aol.com wrote: Hi Dave, forgot to mention: The PRS-10 also has a limited temperature range only up to +65C, so military applications are a no-go. A good DOCXO will have +75C or even +85C capability. Also, the spec for the PRS-10 is 1.18E-012 per Degree C temperature change, and the units I mentioned before with the DOCXO are available in better than 2E-012 per Degree C over a wider temp range, so are very similar in performance over temperature. bye, Said In a message dated 11/19/2010 18:12:13 Pacific Standard Time, saidj...@aol.com writes: Hello Dave, as some folks have already mentioned here, the best solution for you will depend on your specific requirements in terms of how much warmup time you have before GPS is gone, and how much drift your solution can handle. The PRS-10 is a good unit, but requires cooling, a large amount of power, only has a single 10MHz and 1PPS output, and it has a somewhat noisy output in terms of phase noise and short-term-stability. It also costs about $1500, is quite large, and does not provide a GPS receiver, nor one especially optimized for timing. You may want to look at the Fury or FireFly-IIA GPSDO units, these are lower cost, include the complete GPS sub-system, achieve performance similar to the PRS-10 after sufficient warmup, are much smaller, lower power, the FireFly-IIA has a built-in isolated distribution amplifier, and don't have an Rb lamp life limitation. Typical Fury DOCXO units can achieve better than 1us drift over 24 hours after they have fully stabilized, which is better than many Rubidium references. If you are looking for drift in the 10us range per day, you will need a double oven SC-cut OCXO. You didn't mention if your application was airborne, in that case you may need a low-g sensitivity oscillator to avoid loss of short term stability and increased phase noise due to aircraft vibration and acceleration. Rubidiums are especially sensitive to airborne vibration such as caused by Turboprops, Rotorcraft, etc. Without having your specifications for the warmup time, thermal changes, and the desired drift, it is difficult to say if a single oven, double oven, Cesium, or Rubidium based unit would work for you. Lastly, unless you are underwater or under-ground, GPS should be available with a modern, good jamming-resistant receiver, and if it is a modern GPSDO will perform as well or better than a modern Rb. bye, Said In a message dated 11/19/2010 14:43:43 Pacific Standard Time, li...@rtty.us writes: I had assumed that a Rubidium oscillator would give me the best stability over the course of 8-12 hours. Obviously a Cesium would be better but those are impractical due to cost and power constraints. I've begun evaluation of a Rb oscillator but now I'm being told by some people that a good DOCXO is likely to give me similar medium term stability (with obviously better short-term stability). Anyone here have thoughts on this? Obviously I'd rather go with a DOCXO for cost and power reasons if there's no performance benefit to be had using a Rb osc. The Rb unit I'm testing (http://www.thinksrs.com/products/PRS10.htm) seems to perform well but I am interested in hearing others' thoughts. Thanks, Dave -- Dave Jabson Systems Engineering Manager Quasar Federal Systems 5754 Pacific Center Blvd, Suite 203 San Diego, CA 92121 858-412-1706 www.quasarfs.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] DOCXO vs. Rubidium medium-term stability
On Nov 19, 2010, at 7:06 PM, Bob Camp li...@rtty.us wrote: Hi If high temperature is an issue, keeping the Rb cool will be a major chore. The OCXO will be far more happy at 75 than the Rb will be at 65. Depending on just how mobile we're talking about, the OCXO may have some issues with 2G tip / acceleration. There's a lot to consider in a setup like this and without a bit more data we're going to head off into crazy land pretty fast. Bob Crazy land? On time-nuts? I suggest a carefully balanced pendulum made of a Pt-Ir alloy driven by a water powered escapement. grin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Laser oscillator distance measurement ckt
On 18/11/10 18:25, lstosk...@cox.net wrote: I want to build a simple digital tape measure for the range from near zero to perhaps 10 ft with some remote output. The off the shelf units are accurate to perhaps 1/16 inch, but do not provide continuous outputs. The Bluetooth units seem to require pushing a button for each measurement. The AR4000 uses an open loop oscillator method: Laser on, beam to target, reflected to photodiode (the time delay we want), then detected, amplified to turn off the laser, photodiode (decides) no light and turns the laser on (time to be minimized). Measure the frequency and calculate the distance. The AR4000 has oscillation frequency of about 50 MHz at zero distance (the circuit delay) and about 4 MHz at 50 ft. Easily measured. Circuit looks pretty easy with modern devices. Anyone already have something or ideas for best devices? Thanks, N0UU By setting up the laser amplitude into a feed-back loop you can use the side-band oscillation frequency. The trick is to measure the period rather than frequency, which should be trivial with a fairly simple reciprocal counter approach. Subtract the internal delay and you have free-flight time which converts into distance, divide by two and then add the correction for distance to reference plane. The oscillating loop need sufficient of gain and possibly an AGC to control the gain not to loose too much optical power. A filter in the feedback path would increase the internal delay, Bessel-Thomson would be preferred for maximum flat group-delay. A reciprocal counter properly done could do averaging as well as provide continous output. For this application overlapping estimator may work well enough. A full reciprocal counter is not needed, a fixed gate time could simplify things and by letting the loop frequency steer a counter it would only need to be sampled regularly for the rest of the processing to be done in software. A maximum frequency of 50 MHz and an internal gate-time of 1 ms would need a 16-bit counter. Reading out a 16 bit number once a ms and increment it internally would be trivial for an 8-bit CPU to deal with. Accumulating bunches of 100 samples would give a read-out rate of 10 Hz and only then you would need to divide the 100 ms with the accumulated 23 bit value, so even a 6502 doing slow division will cope. I guess an AVR would yawn at it. The counter could be implemented in a simple CPLD such as the 9536... hook it up to an AVR and you are almost there. Once the feedback-loop is operating, the counter side can be attempted with existing counters initially and the transferred to the dedicated counter. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
