[Discuss-gnuradio] QPSK Modulation and Demodulation Question

Hello All,

I am using the Gnuradio for two weeks. I am doing the Gnuradio tutorial 7 on stage 5. There I used PSK demod to demodulate the signal. I do not know why the output signals are different than input signal. This is the screenshot of my blocks. Is that because my vector source influence the result or should I use the My_Qpsk_demod block on tutorial 4.

Thanks

Fan