Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements
Have you looked at the blitzortung.org system? There may be some ideas to glean from that On July 28, 2016 6:12:54 PM CDT, Jerome Blaha wrote: >Hi Guys, > >This is a little outside of time-nuts scope, but not by much. I'm >interested in finding the time between two rising edges above a set >threshold with preferably nS or high ps timing accuracy. Can this be >simply done with a few programmed Microchip PICs or with a good short >term OCXO clock? The issue I see is that a 10Mhz timing reference with >1 cycle difference in time yields 100ns resolution, which is far too >large, so maybe a PIC can solve this. > >This weekend project would be a multi-element antenna array, each with >a super-fast response log peak power detector fed into several PICs for >time of arrival. Whenever a nearby high energy RF pulse is detected, >the time of arrival between two antenna elements and hence the >direction toward the TX could be roughly computed. Some typical log >peak detectors have an 8ns input pulse response time, so I'm hoping >that rise times are similar between multiple detectors, negating the >delayed response. > >There are time of arrival/AoA systems out there with synthetic doppler, >phased arrays, correlative interferometers, and phase comparators, but >it would be interesting to accomplish super wideband AoA timing on two >rising pulses with relatively cheap parts. > >Thanks, > >-Jerome >___ >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. -- Sent from my Moto-X wireless tracker while I do other things. ___ 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] Very Accurate Delta Time RF Pulse Measurements
Hi Jerome, This may or may not be of any help, but have you considered using several RTL-SDR devices running at the same time? You'd need to use a common clock, and probably a number of other enhancements. But, if you could pull it off, you'd have a wideband RDF type of device. You'd probably need to include GPS location as part of your datastream and do a lot of offline post-processing. Rather than using the time domain, though, it would probably be easier to put the antennas in a shadow from each other and use the amplitude domain for your post-processing. Bob - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info Original Message > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. I'm interested > in finding the time between two rising edges above a set threshold with > preferably nS or high ps timing accuracy. Can this be simply done with a few > programmed Microchip PICs or with a good short term OCXO clock? The issue I > see is that a 10Mhz timing reference with 1 cycle difference in time yields > 100ns resolution, which is far too large, so maybe a PIC can solve this. > > This weekend project would be a multi-element antenna array, each with a > super-fast response log peak power detector fed into several PICs for time of > arrival. Whenever a nearby high energy RF pulse is detected, the time of > arrival between two antenna elements and hence the direction toward the TX > could be roughly computed. Some typical log peak detectors have an 8ns input > pulse response time, so I'm hoping that rise times are similar between > multiple detectors, negating the delayed response. > > There are time of arrival/AoA systems out there with synthetic doppler, > phased arrays, correlative interferometers, and phase comparators, but it > would be interesting to accomplish super wideband AoA timing on two rising > pulses with relatively cheap parts. > > Thanks, > > -Jerome > ___ > 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] Very Accurate Delta Time RF Pulse Measurements
On Fri, 29 Jul 2016 09:23:02 -0700 Chris Albertson wrote: > Sounds like you want to build something rather then use some > instruments you can buy. I've thought a little about this too as I > want to make a LIDAR to measure distance using a laser pulse. In my > case I want both low cost and for the device to be very small and > light and run off a battery For this kind of application I would recommend looking into chips like the TDC1000 (there are multiple in this family, and other manufacturers have similar chips). They are made exactly for that kind of application, though with ultrasonic flow measurement in mind. The timing resolution is high enough that you can build a LIDAR with <10cm resolution that does consume very litte power. For higher resolution, I would go for a sinusoidal modulation scheme and measure the phase difference between the transmitted and received signal. That should easily give you resolution in the sub-cm range, but also consumes more power. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] Very Accurate Delta Time RF Pulse Measurements
Hi Jerome: The Vietnam era Radar Warning Systems used 4 wide band antennas (nose, tail & wing tips) and displayed the bearing, rough distance & threat type on a CRT. Near the antenna was a crystal video receiver using a multi channel filter driving Schottky diode detectors. The output from each detector fed a video log amp. http://www.prc68.com/I/RWR.shtml http://www.prc68.com/I/ALR54.shtml The Fenwick antenna patent based on time delay beam steering is far superior to a phased array in that it's frequency independent. http://www.prc68.com/I/Ant.shtml#TDBS I think the basis of TOA. Can you say more about the specifics of what you are trying to do? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Guys, This is a little outside of time-nuts scope, but not by much. I'm interested in finding the time between two rising edges above a set threshold with preferably nS or high ps timing accuracy. Can this be simply done with a few programmed Microchip PICs or with a good short term OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle difference in time yields 100ns resolution, which is far too large, so maybe a PIC can solve this. This weekend project would be a multi-element antenna array, each with a super-fast response log peak power detector fed into several PICs for time of arrival. Whenever a nearby high energy RF pulse is detected, the time of arrival between two antenna elements and hence the direction toward the TX could be roughly computed. Some typical log peak detectors have an 8ns input pulse response time, so I'm hoping that rise times are similar between multiple detectors, negating the delayed response. There are time of arrival/AoA systems out there with synthetic doppler, phased arrays, correlative interferometers, and phase comparators, but it would be interesting to accomplish super wideband AoA timing on two rising pulses with relatively cheap parts. Thanks, -Jerome ___ 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] Very Accurate Delta Time RF Pulse Measurements
Sounds like you want to build something rather then use some instruments you can buy. I've thought a little about this too as I want to make a LIDAR to measure distance using a laser pulse. In my case I want both low cost and for the device to be very small and light and run off a battery I think the way to do this is to have a function generator that creates a ramp function that moves from zero to some max volts in 100 ns. Then when the pulse arrives you use that to trigger a capture of the ramp's current voltage into a sample and hold. Then later look at the difference in the volts in each sample and hold.If the time difference is longer than one ramp period then you need to also sample the counts in a normal counter for each pulse edge. I guess you might use a PIC to implement the above but I find it is always easier to write software on a larger computer. The aded cost of using more expensive device is nothing if it saves hours or days of effort (and you are only building one unit.) You could use the uP internal counter to measure the rough time interval and whatever drives that internal counter would also drive the ramp function generator >> This is a little outside of time-nuts scope, but not by much. I'm >> interested in finding the time between two rising edges above a set >> threshold with preferably nS or high ps timing accuracy. Can this be >> simply done with a few programmed Microchip PICs or with a good short >> term OCXO clock? The issue I see is that a 10Mhz timing reference >> with 1 cycle difference in time yields 100ns resolution, which is far >> too large, so maybe a PIC can solve this. >> >> This weekend project would be a multi-element antenna array, each with >> a super-fast response log peak power detector fed into several PICs >> for time of arrival. Whenever a nearby high energy RF pulse is >> detected, the time of arrival between two antenna elements and hence >> the direction toward the TX could be roughly computed. Some typical >> log peak detectors have an 8ns input pulse response time, so I'm >> hoping that rise times are similar between multiple detectors, >> negating the delayed response. >> >> There are time of arrival/AoA systems out there with synthetic >> doppler, phased arrays, correlative interferometers, and phase >> comparators, but it would be interesting to accomplish super wideband >> AoA timing on two rising pulses with relatively cheap parts. >> >> Thanks, >> >> -Jerome >> ___ >> 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. > > > -- > WBW, > > V.P. > ___ > 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. -- Chris Albertson Redondo Beach, California ___ 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] Very Accurate Delta Time RF Pulse Measurements
May be some more accurate alternative to AD8302 could do that. AD8302 could measure Gain/Loss and Phase up to 2.7 GHz. I using one in my project and its doing its job right (I think). On 2016-07-28 19:12, Jerome Blaha wrote: Hi Guys, This is a little outside of time-nuts scope, but not by much. I'm interested in finding the time between two rising edges above a set threshold with preferably nS or high ps timing accuracy. Can this be simply done with a few programmed Microchip PICs or with a good short term OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle difference in time yields 100ns resolution, which is far too large, so maybe a PIC can solve this. This weekend project would be a multi-element antenna array, each with a super-fast response log peak power detector fed into several PICs for time of arrival. Whenever a nearby high energy RF pulse is detected, the time of arrival between two antenna elements and hence the direction toward the TX could be roughly computed. Some typical log peak detectors have an 8ns input pulse response time, so I'm hoping that rise times are similar between multiple detectors, negating the delayed response. There are time of arrival/AoA systems out there with synthetic doppler, phased arrays, correlative interferometers, and phase comparators, but it would be interesting to accomplish super wideband AoA timing on two rising pulses with relatively cheap parts. Thanks, -Jerome ___ 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. -- WBW, V.P. ___ 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] Very Accurate Delta Time RF Pulse Measurements
On Thu, 28 Jul 2016 23:12:54 + Jerome Blaha wrote: > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. > I'm interested in finding the time between two rising edges above a set > threshold with preferably nS or high ps timing accuracy. Can this be simply > done with a few programmed Microchip PICs or with a good short term OCXO > clock? The issue I see is that a 10Mhz timing reference with 1 cycle > difference in time yields 100ns resolution, which is far too large, so maybe > a PIC can solve this. I think the easiest way is to implement something like the PICTIC II [1]. That should get you into the order of 100ps with minimal effort. With a little bit of care, you can make it go down to 20-30ps rms. But I think, that the pulse generation itself is probably the part that limits your precision, as the logarithmic amplifiers are usually quite noisy. Attila Kinali [1] http://www.ko4bb.com/doku2015/doku.php?id=precision_timing:pictic -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson ___ 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] Very Accurate Delta Time RF Pulse Measurements
Taking a look for it also turned up a recent time-nuts thread https://www.febo.com/pipermail/time-nuts/2016-May/097801.html On Thursday, 28 July 2016, Scott Stobbe wrote: > There was a pic app note on alternate uses for the cap sense block a while > back, not sure it that it will push you into the ps. > > On Thursday, 28 July 2016, Jerome Blaha > wrote: > >> Hi Guys, >> >> This is a little outside of time-nuts scope, but not by much. I'm >> interested in finding the time between two rising edges above a set >> threshold with preferably nS or high ps timing accuracy. Can this be >> simply done with a few programmed Microchip PICs or with a good short term >> OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle >> difference in time yields 100ns resolution, which is far too large, so >> maybe a PIC can solve this. >> >> This weekend project would be a multi-element antenna array, each with a >> super-fast response log peak power detector fed into several PICs for time >> of arrival. Whenever a nearby high energy RF pulse is detected, the time >> of arrival between two antenna elements and hence the direction toward the >> TX could be roughly computed. Some typical log peak detectors have an 8ns >> input pulse response time, so I'm hoping that rise times are similar >> between multiple detectors, negating the delayed response. >> >> There are time of arrival/AoA systems out there with synthetic doppler, >> phased arrays, correlative interferometers, and phase comparators, but it >> would be interesting to accomplish super wideband AoA timing on two rising >> pulses with relatively cheap parts. >> >> Thanks, >> >> -Jerome >> ___ >> 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] Very Accurate Delta Time RF Pulse Measurements
Hi If you have a need to do < 1 ns with a counter approach, the counter will need to have a GHz clock in it. If you want to use an MCU counter, it will need to have a GHz level clock routed to it. You are unlikely to find an MCU that will do that. An FPGA can get you to 1.25 ns with direct counting. With gate based delay line techniques you can get down below 100 ps in an FPGA. The other approach is to build a counter to get as fast as you practically can and then do an analog TDC to get a few more bits. There are a *lot* of messy details past all that. Bob > On Jul 28, 2016, at 7:12 PM, Jerome Blaha wrote: > > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. I'm interested > in finding the time between two rising edges above a set threshold with > preferably nS or high ps timing accuracy. Can this be simply done with a few > programmed Microchip PICs or with a good short term OCXO clock? The issue I > see is that a 10Mhz timing reference with 1 cycle difference in time yields > 100ns resolution, which is far too large, so maybe a PIC can solve this. > > This weekend project would be a multi-element antenna array, each with a > super-fast response log peak power detector fed into several PICs for time of > arrival. Whenever a nearby high energy RF pulse is detected, the time of > arrival between two antenna elements and hence the direction toward the TX > could be roughly computed. Some typical log peak detectors have an 8ns input > pulse response time, so I'm hoping that rise times are similar between > multiple detectors, negating the delayed response. > > There are time of arrival/AoA systems out there with synthetic doppler, > phased arrays, correlative interferometers, and phase comparators, but it > would be interesting to accomplish super wideband AoA timing on two rising > pulses with relatively cheap parts. > > Thanks, > > -Jerome > ___ > 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] Very Accurate Delta Time RF Pulse Measurements
There was a pic app note on alternate uses for the cap sense block a while back, not sure it that it will push you into the ps. On Thursday, 28 July 2016, Jerome Blaha wrote: > Hi Guys, > > This is a little outside of time-nuts scope, but not by much. I'm > interested in finding the time between two rising edges above a set > threshold with preferably nS or high ps timing accuracy. Can this be > simply done with a few programmed Microchip PICs or with a good short term > OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle > difference in time yields 100ns resolution, which is far too large, so > maybe a PIC can solve this. > > This weekend project would be a multi-element antenna array, each with a > super-fast response log peak power detector fed into several PICs for time > of arrival. Whenever a nearby high energy RF pulse is detected, the time > of arrival between two antenna elements and hence the direction toward the > TX could be roughly computed. Some typical log peak detectors have an 8ns > input pulse response time, so I'm hoping that rise times are similar > between multiple detectors, negating the delayed response. > > There are time of arrival/AoA systems out there with synthetic doppler, > phased arrays, correlative interferometers, and phase comparators, but it > would be interesting to accomplish super wideband AoA timing on two rising > pulses with relatively cheap parts. > > Thanks, > > -Jerome > ___ > 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] Very Accurate Delta Time RF Pulse Measurements
Hi Guys, This is a little outside of time-nuts scope, but not by much. I'm interested in finding the time between two rising edges above a set threshold with preferably nS or high ps timing accuracy. Can this be simply done with a few programmed Microchip PICs or with a good short term OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle difference in time yields 100ns resolution, which is far too large, so maybe a PIC can solve this. This weekend project would be a multi-element antenna array, each with a super-fast response log peak power detector fed into several PICs for time of arrival. Whenever a nearby high energy RF pulse is detected, the time of arrival between two antenna elements and hence the direction toward the TX could be roughly computed. Some typical log peak detectors have an 8ns input pulse response time, so I'm hoping that rise times are similar between multiple detectors, negating the delayed response. There are time of arrival/AoA systems out there with synthetic doppler, phased arrays, correlative interferometers, and phase comparators, but it would be interesting to accomplish super wideband AoA timing on two rising pulses with relatively cheap parts. Thanks, -Jerome ___ 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.
