Bob wrote: > Drive the other channel with the pps out of the SRS-725 > Feed the output out the serial port to a terminal program for logging. > > You will see a series of delta time numbers. If you are getting deltas under > 1 us
Note also that typically, only one edge of a PPS pulse is held to a high standard of accuracy (almost always the leading edge, which can be either the rising or falling edge depending on the design). So, while it might seem convenient to just flip the trigger polarity on one input to get a TI that is always positive, you don't want to do that -- each input should trigger on the designated "timing edge" of the PPS. Then, if the TI is too short for comfort, adjust the position of one of the pulses -- either by using the cable delay setting of the GPS as detailed by Bob, or by using a short piece of coax to the source with the earlier PPS pulse and a longer cable to the later source. (If you use a long cable run, remember that the propagation velocity of coax changes with temperature, so do your best to minimize temperature variations.) Best regards, Charles _______________________________________________ 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.
