I recently obtained a FEI FE-5680A Rb standard Revision: B. After powering it up 'out of the box', a lock @ 50.25505.. MHz was obtained within a few minutes, confirmed by measuring the lock indicator on pin 3 of J1 and listening to the signal on my FT 857 receiver. Nice to hear it sweeping before locking ;-) Here te levels at pin3 of J1 are: unlocked +4V, locked +1.5V
A 1PPS signal could not be detected with a multimeter, so I connected a scope. I consider the signal levels somewhat peculiar and am curious if FE 5680A owners here have the same experience. E.g. the amplitude of the PPS signal at pin6 is superimposed on a DC offset of ca. 170 mV and amounts (only?) 25 mV. It is visible as a small spike here (depending upon the time base of course). My perception of a '1PPS' signal is a signal with TTL levels or open collector out or something, and a pulse width of 10 - 200 ms.. I connected a 2k2 resistor between pin6 and pin1 (pull up) but could not see any improvement. The top-top amplitude remained ca. 25 mV. Pin6 (measured with scope) spikes with t = 1 sec: 200mV | | | 170mV ------|------|------| The signal above will be hard to interface, but I feel that perhaps the PPS output is not 'set' or perhaps broken. After powering up, the unit draws 1.6A which gradually decreases to 800mA. This looks normal. Anyone any ideas? _______________________________________________ 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.
