Re: [Discuss-gnuradio] Problem with USRP2 continuous transmission at >10MHz

[Matt Ettus]

hanwen wrote:
> Hi,
>
> We use tx_samples.cc to transmit a file with 16bit-short complex samples 
> at 10MHz and 20MHz. We use another USRP2 to receive the signal and store 
> on disk. We observed there are some unexpected gaps in the received 
> samples. Using usrp2_fft.py with the osiliscope view, we also observed 
> such kind of gaps.
> We guess this might be caused by underrun at the transmitter side. We 
> use the delievered ethernet cable, so this shouldn't be the problem of 
> bad cable.
> Anyway, how can we transmit samples contineously and stably without 
> underrun at 20MSamples/s??


1 -- Make sure you have realtime scheduling enabled
2 -- Use a very fast computer

are you sure you are seeing underruns?  Have you connected to the debug 
serial port on the USRP2 and seen it send "U"?

Matt