This a somewhat crude, proof-of-concept, not robust, decoder for the timesignal broadcast by DCF77 on 77.5 kHz.
It is to be used by first opening http://websdr.ewi.utwente.nl:8901/ in one browser tab, tuning to 77.5 kHz CW, then opening this page in a second tab, and then having some patience.
I've tested it under Firefox, and it may also work under Chrome and Opera; other browsers lack the necessary communication between tabs.

Comments about this page can be sent to pa3fwm@websdr.org.

Status: Connecting to WebSDR tab

Incoming signals (amplitude of 77.5 kHz carrier):

Incoming bits:

Bits received during previous minute: 


                              | | | | |   -------------   -----------   ----------- ----- --------- ---------------
                              | | C C |      minutes         hours          day    weekday  month        year  
                              | | E E |                                                                      
 abnormal transm. operation --' | S T |  
     summer time announcement---' T   |
       leap second announcement ------'

Detailed information about the signal and the individual bits can be found on Wikipedia.