[Discuss-gnuradio] QAM Mod / Demod blocks

Dear Sir,

I am learning to use the built-in "QAM Mod" and "QAM Demod" blocks.

Refer below flowgraph.

The problem is, at the output of the "QAM Demod" block, I can't get what I fed into the "QAM Mod" block.

What is missing ..?

​