On a couple that I bought there was no response to pots, the only frequency adjust was through the DDS chip. I wanted to beat it to 1E-30 (kidding) but had to be content with the DDS granularity close to 1E-13. Good enough, considering all other sensitivities that will degrade beyond that (turn it upside down and watch a 4E-11 change).
Some other variants reportedly respond to the trimpot, others have real wide range DDS, allow 3MHz if you set it so. Although output filter might need tweaking if you are way off the intended range. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peter Bell Sent: Thursday, November 10, 2011 2:38 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A As far as I can see, the trimpot has no effect at all - the only frequency trim on the unit is via the RS232 interface on pins 8 and 9 of the connector I suspect this is adjusting the c field, but have not actually verified this. It does definately change the output frequency, though. On Nov 11, 2011 6:17 AM, <[email protected]> wrote: > > Thank you Peter > With Jose's and your input I will power it up in the morning. Mine has the > same part # and a date code 0330. Does yours respond to the trim pot, I > plan to bring out the tuning voltage to a modified Shera controller. > Bert > > > In a message dated 11/10/2011 5:03:07 P.M. Eastern Standard Time, > [email protected] writes: > > Assuming it's the same as the units I have (two labels, with "FEI P/N > 217400-30352-1" on the upper label and two barcodes on the lower > label) then the +5V supply runs all the logic in the unit. There are > no special power sequencing requirements, but you need both supplies > for the unit to operate. The current drain on the 5V line is fairly > low - about 90mA - the 15V will pull about 2A when the unit is cold > and then drops to 500-600mA once everything is warmed up. Pin 3 is > the lock indicator - driven low when locked. The output (10MHz sine) > is present on pin 6, and appears immediately after power up - although > the frequency is not accurate until the lock pin is asserted. > > The 4 digit prefix on the lower barcode is a date code - so "S/N > 0416-77234" would indicate a unit made in week 16 of 2004. > > Regards, > > Pete Bell > > On Fri, Nov 11, 2011 at 12:30 AM, <[email protected]> wrote: > > I did purchase one of the "New" FE-5680A Rb's. Looking at packaging and > > the housing it does look new. I have not powered it up because of +5 > Volt on > > pin 4. Does any one know its purpose and is there a power up sequence. > Any > > help will be appreciated. > > Bert Kehren Miami > > _______________________________________________ > > 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. > _______________________________________________ > 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. _______________________________________________ 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.
