Re: [Discuss-gnuradio] Strange "UUUU" pattern

[Chesir, Aaron M.]

Folks,

 

I found the error: The “U” characters indicated an underrun to my USRP transmitter. I reduced the sample rate form 5e6 to 2e6, and the underrun indicators went away.

 

My problem in my receiver was that I was zoomed in to much in frequency span in my FFT display to see that I was indeed receiving my signal.

 

Aaron

 

 

From: Chesir, Aaron M.
Sent: Friday, March 15, 2019 10:21 AM
To: address@hidden
Subject: Strange "UUUU" pattern

 

Folks,

 

I have a simple QPSK modulator feeding its output into the input of my USRP transmitter. I notice two oddities:

1. The status window at the bottom produces a sequence of “U” characters until I stop the run, and
2. The receiver does not detect any presence of any signal (I have a receive process on another computer feeding the output of the RTL SDR to an FFT, and is attached to this email)

 

When I replace the QPSK modulator at my transmitter with a simple cosine generator, the receiver shows the presence of the signal with no problem, and I don’t see those strange “U” characters at the source GRC process.

 

Can someone offer suggestions at what I should fix?

 

Thanks,

 

Aaron