[Discuss-gnuradio] Strange error on running TX/RX scripts

[Meenal]

Hi all,
I am writing FM TX and RX scripts similar to  the FSK TX and RX
scripts found in gnuradio-examples/python/usrp1

I have noticed that when running these scripts, they seem to work
correctly, but strange characters like "aUaU..."  appear
on my session window and continue appearing  till I terminate the
program. 

---------------------------------------------
address@hidden gui]$ python fm_tx.py
audio: using audio_alsa
alsa_sink: min_nperiods = 1, max_nperiods = 1024
aUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaUaU....

How can I fix this?
Many thanks,
Meenal