You can put me in the "No 1 PPS on pin 6" camp, too - I made extensive attempts to detect it on the first couple of units (multiple scopes, even connecting in to an edge-sensitive interrupt pin) and detected nothing. The other units, I just poked a scope (TDS420A) at it, but could see nothing.
One thing I did notice was that in one of the photos on here (the one about the 5V switching regulator) there were some components ('AC161 and associated parts) installed on the PCB that were not present on any of the units I opened. This may be related, or may not - but at the least it does suggest that despite having the same P/N these units might not all have the same build spec. Regards, Pete Bell On Thu, Jan 12, 2012 at 12:54 AM, beale <be...@bealecorner.com> wrote: > 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 <albertson.ch...@gmail.com> >> To: Discussion of precise time and frequency measurement >> <time-nuts@febo.com> >> Subject: Re: [time-nuts] FE-5680A arrived >> Sent: 11 Jan '12 08:37 >> >> On Tue, Jan 10, 2012 at 10:11 PM, Joseph Gray <jg...@zianet.com> 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 -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.