A used Spirent is only 26K to 37K. Interesting: playing back bits from RAM... can it be that simple? Obvious: a DAC is required.
On Fri, Dec 16, 2011 at 3:47 PM, Jim Lux <[email protected]> wrote: > On 12/15/11 10:25 PM, Chris Albertson wrote: > >> For testing, I'd assume the gps simulator only needs to be good enough >> that the receiver will detect the signal. There is some Doppler >> shift so the receiver must have to look over a wider range of >> frequencies so if the simulator was inside that range it could work. >> Light travels at about one foot per nanosecond. so your simulator >> should need to know the time to within a few tens of nanoseconds. >> Receivers can deal with not-perfect signal. Multipath and refraction >> are common. >> >> > Not just functional test, but to verify the "added noise" from the > receiver. > > TO just see if it can acquire and track, pretty crummy would work, because > it's just like the horrible signals it's seeing "off the air" > > > You GPS simulator would likely have a GPS receiver inside of it and >> sync to a real GPS. >> > > Not necessarily. You might be testing in a screen room with no external > signals available. > > Clearly, one can go out and spend 500k on a nice Spirent, but I'm looking > at what is the few hundred dollar solution. A reasonably quiet oscillator > driving an FPGA or playing back bits from RAM > > > > On Thu, Dec 15, 2011 at 9:37 PM, Jim Lux<[email protected]> wrote: >> >>> Say you want a quik n easy n cheap GPS simulator to test a GPS timing >>> receiver. How good does the oscillator (presumably some nice multiple of >>> the chip rate) have to be? >>> >> > > ______________________________**_________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/** > mailman/listinfo/time-nuts<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.
