Hi Warren: Here's some info on a GPS signal generator made by Stanford Telecom for testing their GPS ICs: http://www.prc68.com/I/5001A.html I'm sure it could be greatly reduced in size and complexity be replacing all the logic with a micro controller, but the RF part would remain. There is a very strong correlation between the hardware and the ICD-200 GPS spec.
Have Fun, Brooke Clarke http://www.prc68.com WarrenS wrote: > In my quest to keep improving my GPSDO, a simple test tool > that I find indispensable is a GPS 1PPS (or 100Hz) signal simulator > reference. Others may also find this useful because it allows testing the > PLL & DO in their GPSDO to Cs type accuracy using a standard OCXO. > > The advantages of using the 1PPS GPS signal simulator instead of the > real thing for high accuracy test, is that it eliminates all the errors and > unknowns > that come before the 1PPS signal so that the performance and limitations of > just the PLL and it disciplined oscillator can be quickly tested > independently > of the receiver and the GPS signal. > This also gives higher accuracies than are available from the GPS system, > while using a relatively low accuracy oscillator for its reference. > > The simulator generates the 1PPS signal from a divided down > standard 10MHz OCXO. > For advanced test a simple Phase modulated 'Noise' can be added to the > 1PPS to represent the basic phase noise of the GPS receiver's 1PPS signal. > The phase & freq difference between the reference oscillator and the > tracked PLL oscillator can then be compared to any desired accuracy > and resolution limited by the noise, but not the accuracy, of the > oscillators. > > > Now I am wondering: > Has anyone made or considered the tricks needed to simulate a GPS > RF signal in a simple and cheap way? > Something that could be used to send a 1PPS timing signal to a GPS receiver > for similar basic high accuracy receiver testing from the antenna to the > 1PPS? > It would seem that this may be feasible when used with a receiver that can > output its 1PPS when locked to a single satellite? ? ? > > WarrenS > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
