[time-nuts] could you please post this?

rjb0343 at aol.com rjb0343 at aol.com
Mon Dec 21 16:45:26 UTC 2009


 
FTS 6102 Frequency Comparator  -info needed 
Does anyone have any info on this  Frequency & Time Systems unit? I have 3 
and each is slightly different  externally but the innards seem to be the 
same. Each unit has a low 2-digit S/N  so I’m not sure how many were actually 
made or if any of them were production  units. I.C. date codes indicate a 
1987 date. I have quickly checked the circuit  board to see if I could figure 
out what goes on and have included a link to a  photo of the input section 
of the circuit board. There are 2 floating BNC inputs  (A & B) that go 
through isolation transformers to buffers then to a phase  detector. From the 
parts used it appears the circuit might be usable from near  d.c. to about  
100Mhz. The phase detector gives a d.c. voltage proportional to the phase  
difference and seems to be followed by RC low-pass filtering feeding the op-amp,  
which seems to make sense. There are 2 output BNC connectors marked ‘A-B’ 
and  ‘analog’  
There are also two LM211 voltage  comparators that may be used to trigger 
the 8-digit counter chip that drives the  front panel display. You can select 
3 of the 8 digits with a switch and  apparently the numeric value of that 
3-digit number is converted with a 12-bit  D-A converter to drive a recorder 
or whatever. Four decade averaging periods are  also selectable. There is 
also a 25 pin ‘D’ connector on the rear marked  ‘controller’ but I’m not 
sure what that does as if it doesn't  seem necessary to use the unit as a 
comparator. A quick test indicates the  units at least work. More testing is 
needed to see how useful they might  be. 
Any information would be  appreciated.  -Richard 
Front Panel photo link   
_http://farm3.static.flickr.com/2665/4203550480_70f27cb15e.jpg_ 
(http://farm3.static.flickr.com/2665/4203550480_70f27cb15e.jpg)  
Circuit Board photo  link _
http://farm3.static.flickr.com/2785/4203550698_cb648b4e35.jpg_ 
(http://farm3.static.flickr.com/2785/4203550698_cb648b4e35.jpg)  


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