Hello all,
Greetings of the day!
I am going through the GNU Radio tutorials and currently I am at the "QPSK Mod and Demod" chapter.
Here, in the "mpsk_stage_2.grc" project, a "Channel Model" block has been used. My question is about some fields of this block:
1. I checked from the details of that particular block that "frequency offset" is entered in terms of a fraction of the "symbol rate". Now my doubt is about the fact that nowhere in the block the "symbol rate" is input. Then how can this block calculate the "frequency offset" having the fraction data only in hand?
I am aware of the fact that there are variables "sample rate" and "sps (samples per symbol)" in the design. However, when the data enters the "Channel Model" block, they are entering as samples at a particular "sampling rate". This "Channel Model" does not have any information about how many samples represent one symbol.
2. In the "Taps" field, "1" has been given in the example. However, I checked from the details of that particular block that for no multipath case it should be "1+1j". I have also observed changes in the "Constellation Sink" plot for these two values. What is the difference between the "1" and "1+1j" applied in the "Taps" field?
Thank you.
With regards,
Shuvodip Majumdar