DCF77 Reciever

a larger picture is here

My DCF 77 reciever is made back in 1992, the recieve freq is 77.500 KHz
It has 3 filter stages, and a AGC, Automatic Gain Controll
The Detector output is gained in a op-amp and compared with a variable voltage "trig"
the output of this comperator give the data information pulses, that comes every sec
if the pulse is 200ms it represent a digital 1
if the pulse is 100ms it represent a digital 0
if nopulse is recieved, that mean a new minute has begon
there is a lot of literature about the DCF77 signals on the net, so I dont bother to have it here

Download my rapport from 1992 with all doc and schematics (text is in Danish)