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Homemade Radio Electronics
DCF77 Receiver hardware and software explained

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

Download my Software rapport from 1992 with all source code too (text is in Danish)

Done 1992 by Kenny And me :-)