[Discuss-gnuradio] GnuRadio: Clock Recovery MM: imu out of bounds

[Michael B]

I have created a flowgraph, based on an example of Michael Ossmann, which takes in a signal, and should output bits.

I need to use the clock recovery MM block, which I do not fully understand yet. However, after reading some blogposts, I am quite sure that I can leave most of the settings default, except for the Omega one. Here's my flowgraph:

http://imgur.com/pHRXnZu

When running this flowgraph, it gives me the following error:

thread[thread-per-block[5]:<block clock_recovery_mm_ff (9)>]: mmse_fir_interpolator_ff: imu out of bounds.



While searching, I stumbled upon this piece of code in the source of GnuRadio:


int imu = (int)rint(mu * NSTEPS);  
  if((imu < 0) || (imu > NSTEPS)) {
    throw std::runtime_error("mmse_fir_interpolator_ff: imu out of bounds.\n");
  }

So, I suspect it is not due to my Omega setting (which might be wrong, I have to play with that setting), but that it is due to my Mu setting, which is just the default (0.5). However, I understand that Mu needs to be between 0 and 1, so I do not really understand what the problem is. Anyone who does?

Environment details:

• GNU Radio Companion 3.7.7.1
• Running a GNU Radio live DVD in a virtual machine (VirtualBox 4.2.12) on Windows 7.
• Using Volk machine: ssse3_64