Mapping for QPSK Modulation

Hi,

I’m quiet new to GNU Radio and I’m trying to build a QPSK Modulator in
GNU Radio. As the input signal I want to use a random source with a
minimum of 0 and a maximum of 256.
Then I want to map the bits of the byte stream created by the random
source to complex symbols. In the case of QPSK I want to map them to:

  • 00 -> +1+1j
  • 01 -> -1+1j
  • 10 -> -1-1j
  • 11 -> +1-1j

So, what I tried to do was to unpack the bytes of the random source.
After that I putted a “chunks to symbol” block. Is this actually the
right way? Because I don’t know how to do the mapping on the “chunks to
symbol” block. Or can I do the mapping in a different way?

Thank you in advance!