Mark Sims wrote: > > My first inclination, if I were building a timing receiver, would be to > make the PPS output a nice, symmetrical square wave. But pretty much > all GPS timing receivers output an anorexic, dinky little heroin addicted > supermodel sized pulse (from 1 to 150uS wide is typical). > _______________________________________________
One reason might be that it is convenient to have AC coupled hardware, with a reasonable low frequency cutoff. 1 Hz is not a reasonable low frequency cutoff, which is what you would need if a square wave were used. (Actually, to accurately reproduce a 1 Hz square wave requires response down to .1 Hz and preferrably .01 Hz, due to droop and phase shift distortion issues). A short pulse will conveniently propagate though the same sort of distribution amplifiers used for 10 MHz, 5 MHz, 100 kHz, etc. Rick Karlquist N6RK _______________________________________________ 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.
