[time-nuts] Network Syncronization
Hi, This querry of mine may not be related directly to clocks, but I was just wondering if someone here might know about this! As CDMA networks (and now GSM as well) are SYNCed by GPS, I wanted to know, how a degradation of this sync would affect the network's performance parameters like call drop rate, call handover success rates and others. Thnx Faisal Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. http://videogames.yahoo.com/platform?platform=120121 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] time-nuts Digest, Vol 31, Issue 14
Hi, Thanks for the responce. you are right, some where else i also found 7uS accuracy requirements as well, but these values seem to be a bit older. coz with HSDPA coming up, with bitrate upto 10.8Mbps, bit duration comes out to be 92.6 ns. this might need better synchronization accuracy than 10 or 7uS. I wonder if the accuracy limits have been modified for meeting such data rates?!. What do u say abt this? Regards Faisal At 20:26:49 -0500, Sat, 03 Feb 2007 Mike Swrote... At 07:11 PM 2/3/2007, Phaysal Khan wrote... >Can anyone tell me, how important is timing for network >synchronization ( i am looking forward to some quantitative values), >how much accuracy is expected from timing references, especially GPS >and what are the main services, including CDMA which are using GPS as >timing receivers. IS-97C (Recommended Minimum Performance Standards for Base Stations Supporting Dual-Mode Spread Spectrum Mobile Stations) requires minimun frequency accuracy of 0.05 ppm, and time reference accuracy of 10uS. Food fight? Enjoy some healthy debate in the Yahoo! Answers Food & Drink Q&A. http://answers.yahoo.com/dir/?link=list&sid=396545367 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] CDMA Networks: Timing Requirements
Hi, This would be my mail on the list after a looong break. Hope everyone is fine. Can anyone tell me, how important is timing for network synchronization ( i am looking forward to some quantitative values), how much accuracy is expected from timing references, especially GPS and what are the main services, including CDMA which are using GPS as timing receivers. Regards Faisal The fish are biting. Get more visitors on your site using Yahoo! Search Marketing. http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] M12 product Manual
Hi, Could anyone arrange me M12 product manual. What I am specifically looking on is the sawtooth correction. Regards Faisal - Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Sawtooth Effects in 1PPS
Hi group, Hi, I am currently working on problems with GPS timings, as I said in my previous emails. I presented some of my problems and got quite helping feedbacks. I just wanted to update regarding my progress If u visit the page http://www.leapsecond.com/pages/m12/sawtooth.htm you will found some sawtooth waveforms there. I have been observing the M12, NovAtel OEM4 rcvrs' timing pulses (1PPS) and getting a similar sawtooth effect. but I am unable to findout what is causing such thing. It would be quite helpful for me if anyone could guide me in this regard. Regards Faisal __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] time-nuts Digest, Vol 24, Issue 50
Hi Group, I have been using Leica MC500 PPS pulse and want to get the pps output from that. could any one provide me the socket drawing for the PPS port of Leica MC500 rcvrs. Regards Faisal - How low will we go? Check out Yahoo! Messengers low PC-to-Phone call rates. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] time-nuts Digest, Vol 24, Issue 50
Hi John, I 've just managed to lock the pulse !!. now I am just waiting for my Leica controller to proceed with the puls comparison. Once thru it, i will be posting the results on the group. Thnx for your cooperation! Regards Faisal - Yahoo! Music Unlimited - Access over 1 million songs.Try it free. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Discussion of precise time and frequency measurement
John, At the momet I m trying to do some similar stuff. I want to compare PPS output from two different rcvrs, the reference being Leica MC500 and the subject recvr being M12. but I am having problem with my oscilloscope which is a Tektronix one with 300 MHZ range. It is not locking on to the signal and the signal keeps on sliding sideways (seems to be a triggring problem). by the way, could you let me know what scenario have you build for comparing your signals and what instrument are u using to check the offset between the two. Regards Faisal [EMAIL PROTECTED] wrote: Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to [EMAIL PROTECTED] You can reach the person managing the list at [EMAIL PROTECTED] When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. Re: time-nuts Digest, Vol 24, Issue 47 ([EMAIL PROTECTED]) 2. CDMA time synch problem in Salt Lake City, UT (Dave Andersen) 3. Leap second letters (Bill Hawkins) 4. Re: HP 5370A manual (John Day) 5. Re: GPS jamming (Robert Atkinson) 6. Loran timing experiment (John Ackermann N8UR) 7. Re: Leap second letters (Glenn) 8. Re: Leap second letters (Tom Van Baak) -- Message: 1 Date: Wed, 26 Jul 2006 21:12:12 EDT From: [EMAIL PROTECTED] Subject: Re: [time-nuts] time-nuts Digest, Vol 24, Issue 47 To: time-nuts@febo.com Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset="US-ASCII" Hello Faisal, a small annecdote about GPS jamming from the design of our FireFox GPS Disciplined synthesizers: We have a broadband synthesizer driven by a GPSDO on the same PCB. This synthesizer would completely swamp out the GPS receiption if you set it to 1574MHz CW output, the on-board noise was so powerfull (the output of the unit can be set from DC to 1640MHz). Our output can go up to +18dBm, millions of times more power than the GPS signal itself... The effect was that the M12+ receiver would just loose lock within a +-5 - 10MHz bandwidth around the GPS carrier. The receiver would show 0 sattelites being received. As soon as you set the frequency outside of this band, everything was fine. We improved this by putting the GPS board into a metal shield. So the effect of noise generated inside the enclosure was greatly mitigated. But the CW power radiated by the BNC connector itself on the unit is still enough to find its way to the antenna 10 meters away and about 3m above it, and swamp the signal! Putting a small paperclip into the BNC RF output connector at +18dBm at 1574MHz would probably cause a couple of blocks in our neighbourhood to loose GPS lock :) Never tried this and never will of course. bye, Said -- Message: 2 Date: Wed, 26 Jul 2006 21:14:34 -0400 From: Dave Andersen Subject: [time-nuts] CDMA time synch problem in Salt Lake City, UT To: Discussion of precise time and frequency measurement Message-ID: <[EMAIL PROTECTED]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed I've sent this to EndRun tech support, but since they're not around at the moment, figured I'd run a quick check with people on the list. I don't really expect an "oh, here's your problem", but I'd love one if someone happens to know! I have a somewhat older Praecis Ct (CDMA cellular time receiver) that seems to be having either general problems or leap second problems, or is locking itself to a bad CDMA station. I'm a little baffled. ntpdc> pe remote local st poll reach delay offset disp === *clock.xmission. 155.98.35.100 1 64 377 0.03848 0.664292 0.00499 =ops.emulab.net 155.98.35.100 2 64 377 0.00032 0.629554 0.00421 =GPS_PALISADE(0) 127.0.0.1 0 16 377 0.0 0.000439 0.00023 I reset it and tried again a bit later, with more ntp servers: =nist1.symmetric 155.98.35.100 1 64 1 0.03024 0.681881 7.93750 =clock.xmission. 155.98.35.100 1 64 1 0.03828 0.704977 7.93750 =ops.emulab.net 155.98.35.100 2 64 1 0.00037 0.683862 7.93750 *GPS_PALISADE(0) 127.0.0.1 0 16 37 0.0 0.000297 0.43768 (top is nist1.datum.com, which I'm fairly certain is good) Running the latest firmware from the website: Praecis Ct FW 6010-0001-000 v 2.18 - May 25 2004 16:09:30 Praecis FPGA 6020-0001-000 v 09 The node is located in Salt Lake City, UT, at the University of Utah. My guess, based on the other times I've seen things like this happen, is either: a) It's synched to a CDMA base station that's running some funky version of the spec. This happened a while ago when some sites upgraded to an early version of the CDMA2000 spec, for instance. b) It's synched to a CDMA base station that's just completely lost its c
Re: [time-nuts] time-nuts Digest, Vol 24, Issue 47
Hi, Thats a good stuff grp. I will going thru these and get back to u soon. by the way... i will be doing some experiments with some GPS rcvrs today as well. Regards Faisal - Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1¢/min. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Interference effects to GPS timing
Hi, Thankyou for your responce. My main prob is not to avoid interference but to see how does a GPS timing rcvr behaves in the interferece environment. I have tried to search for articles/papers on interference effects on GPS timing rcvrs, but was unable to find any good stuff. Although GPS timing is in use for last 16 - 17 years, but it seems that ppl take this thing for-granted. could you locate me any such information? Regards Faisal A. Khan - Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] GPS Timing in Interference Environment
Hi, I am new in this group, and wanted to discuss something abt GPS timing. I am working on GPS system & signals from timing point of view. I want to see Effects of Interference(CW) on GPS timing receivers. At this stage I am mainly interested on what will happen to the timing receiver itself when effected by CW interference and the next stage will be to find out how this effect could be mitigated. What I intend to do now, is to compare the 1 PPS pulse from two different rcvrs ( I will be using Motorola M12+ Oncore as the subject rcvr and Leica CRS1000 as the reference. Do you ppl have any suggestions? Regards Faisal __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
