All three of my FE-5680A units show a constant DC voltage on pin 6, with absolutely no PPS signal. This is when pin 3 is low (lock) and the 10 MHz output is indeed locked at 10 MHz (within 4E-10 anyway). I am using a Tek TDS-210 digital scope which certainly has no problem with a 1 usec pulse, and in fact, I did see a nice square 1 usec pulse on Pin 6 once, from one unit. But it went away after a power cycle, and did not return. I know many (most?) people do see the 1 PPS so perhaps all three of my units are damaged (?)
I presume the 1 PPS signal would come from the XC9572 CPLD which also drives the 10 MHz signal, so I'll try tracing back which pin that is. I labelled a few CPLD pins already (60 MHz in, 30 MHz and 10 MHz out) here: https://picasaweb.google.com/lh/photo/dUtTwuNnP-y2nL-wR84ELNMTjNZETYmyPJy0liipFm0 > -------Original Message------- > From: Chris Albertson <[email protected]> > To: Discussion of precise time and frequency measurement <[email protected]> > Subject: Re: [time-nuts] FE-5680A arrived > Sent: 11 Jan '12 08:37 > > On Tue, Jan 10, 2012 at 10:11 PM, Joseph Gray <[email protected]> wrote: > > I'm not seeing a PPS on either of these. All I see is about 17 mV P-P > > of noise that looks like a multi-stepped sine wave. I'm using a TDS > > 340 scope. _______________________________________________ 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.
