Problem with GFSK Mod and Demod example from wiki

Hello everybody,

I want to do some simple test of GFSK modulator and demodulator. I used
an example from wiki - https://wiki.gnuradio.org/index.php/GFSK_Demod .
I copied flowgraph, but my Time sink shows me only signal on input of
modulator - output signal is really weird - some peaks...
Why I can't get the same results as shown on wiki?


Niko