Could it maybe be that you're actually writing the delay value into the chip while the pulse is high? I've had that problem with a DS1023-100. The solution was to wait until the pulse goes low, and then set the delay for the next pulse.
Regards, Tom On Wed, Feb 4, 2015 at 2:47 PM, Dan Kemppainen <[email protected]> wrote: > Martyn, > > In working with a 6T receiver we have noticed that sometimes the reported > offset correction is not correct. These instances appear to be infrequent, > and have only been noted as a single instance at a time. For example you > will occasionally get a -10.2nS correction when you should get a positive > one, or vice versa. Simply changing the sign of the offending correction > value appears to make it correct. > > This doesn't sound exactly like what you are seeing, however. > > Hope the info helps! > > Dan > > > > > On 2/4/2015 12:00 PM, [email protected] wrote: > > Hello, >> >> I am using a LEA-6T GPS chip with the DS1123LE-50 delay line to correct >> the >> jitter of the 1 pps output from the GPS chip. >> >> The correction works very well, dropping the peak to peak jitter of the >> 1pps >> output from about 20 ns to < 3 ns. >> >> However, I randomly get a big jump of the 1 pps pulse, by many >> millisceconds. >> >> After lots of research, checking code and hardware, it seems the >> DS1123LE-50 >> chip randomly produces it's own long pulse. >> >> I have monitored the pulse going into and out of the delay line >> >> The input pulse remains constant (I can't remember exactly the pulse >> width, >> I think 10 us). >> >> But suddenly a large output pulse of many milliseconds appear. >> >> Some chips don't seem to have this problem. Other chips can go wrong, 20 >> times in an hour, then run perfectly for a day or so. >> >> I am blaming my software guy, he is blaming the chip. >> >> Has anyone else used this delay line and seen anything similar? >> >> This chip is now apparently obsolete, but I don't want to change yet as I >> have a few years worth of stock of these chips. >> >> Regards >> >> Martyn >> > _______________________________________________ > 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.
