I've built 2 different DCF Clocks at the last years.
You can find some librarys for dcf decoding in the internet for different Microcontrollers.
To get more information about DCF for exaple look here:
https://en.wikipedia.org/wiki/DCF_77
To decode the signal I used a little Microcontroller.
I programmed a internal crystal based clock, that was syncronized by the dcf signal once in a minute.
The Start condition for decoding is the missing Pulse at the 59 second of the dcf signal.
Then the dcf signal was decoded bit by bit until the missing 59 pulse is arrived again.
A additional counter ensures that the arrived Time Information is correct, e.g. after the minute 34 has to follow the minute 35.
When that goes wrong a Quality counter was set to 0. That will be done at receive errors and changing between Summer- and Winter Time ( Summertime is 1hour forward ).
Only when 6 following Time Informations ( takes 6 complete Minutes ) confirm the changing the internal clock will take the received Time.
Additional in the DCF signal are included some parity bits. On an error the parity goes wrong.
At a double error it could be right again but the information is failed.
With this scheme you get a clock with a absolute correctness of 1 minute.
An additional Idea is to correct the internal second counter at arriving of the 28 second after checking the received parity bits. So you can achieve a absolute correctness of 1 second.
When you only want to have a pulse every second you can use the carrier of the DCF transmitter. The carrier has a frequency of 77,5kHz and is generated out of a atomic clock.
To get a proper signal i suggest you to use a PLL.
I've a source code for an Atmel ATMEGA Controller - Will that be useful for you?
The I'll send it to You via PM.