# /hades/examples/dcf77/*.hds

Hades example design of a DCF77-signal radio controlled clock.
This design demonstrates a medium-complexity gate-level design
with several levels of design hierarchy, and the combination
with a behavioural model (for the sender).

The DCF77 is a German radio station (77 KHz) located near Frankfurt
which uses a simple amplitude modulation to distribute the German 
normal time signal. The sender always sends the data for the next
minute, consisting of 59 bits, with one bit per second.
Each single bit is encoded as a 0.1 or 0.2 second period of low amplitude 
at the start of the second period.  The "missing" bit is used to signal 
end of transmission for one minute of data.
