no peak under lower bandwidth

[youlizhao]

Des.: (1) If we use higher decimation/intepolation value (lower bandwith, e.g., decim: 100 -> 500), we can not find peak any more using STS or LTS (FTW project file); (2) Sometimes, higher bandwidth does not mean the existing of peak. Weird; (3) If we use sleep mechanism to send periodic packets, sometimes not all packets are sent periodic, e.g., we only get 4 packets with equal IPI. Maybe others are lost in queue or struck? (see gr_msg_queue.cc Line 54: while(full_p())) d_not_full.wait(guard)).
Guess: It is caused by CFO. Need validation.
Plan: Sync two usrps, and send the same file with same bandwidth to see whether peaks exist.
Task: Sync two USRP programs;