[Discuss-gnuradio] Basic USRP AM Transmission

[Robert Roberts]

Hello everyone,


I have been experimenting with the Flex400 board and have been trying to
implement a basic AM transmitter. I have a WFM and NFM transmitter
working, but I cannot get the AM one to transmit correctly.   The code
below generates a much higher frequency tone.  Any advice to what I am
doing wrong?   Does my output need filtering before connecting to the
sink?     


self.u = usrp.sink_c ()       # the USRP sink

# Code here for setting up the USRP, omitted

src = gr.file_source (gr.sizeof_float, "audio-1.dat", True) # 440Hz tone
file
const = gr.add_const_ff (1.0)
conv = gr.float_to_complex()

               
gain = gr.multiply_const_cc (4000.0) # transmitter gain

# connect it all

self.connect (src, const)
self.connect (const, conv)
self.connect (conv, gain)
self.connect (gain, self.u)




Thanks,
~Chris~