Hi Olivia,
generally, Python blocks for signal processing are pretty limited in speed; so I'd really
recommend you compare your code's performance with Signal Source (sawtooth) -> frequency
modulator or Signal Source (sawtooth) -> multiply with itself (giving you the square) ->
phase modulator (maybe you remember Lars Gölz's chirp modulation Bachelor Thesis: that's
what he did!).
Other than that, you're sadly not sharing the code of your chirp generation, nor the flow
graph, but only partial screenshots of text – that's not very helpful to help you!
Best,
Marcus
On 14.02.24 12:48, Mammadova, Olivia wrote:
Hello together,
i wrote a code for a linear chirp and added the code to the python generated by grc,
because GNU Radio has no building block for a linear chirp except using Signal source and
VCO Block.
I tried to simulate the linear chirp signal on USRP X410 and send the chirp signa to USRP
X410 l and check the output with the spectrum analyzer. Unfortunately, the simulation
causes underflows and overflows for the sample rate starting at 1 MHz and i cannot
receive a proper linear chirp at UHD Source. Moreover, the CPU Usage during the python
simulation is below 10%.. When i stop the simulation and want to restart the simulation,
RFoncError occurs: Attempting to reconnect input port.
I tried to resize the buffer using sudo nano /etc/sysctl.d/99-custom.conf and added
net.core.rmem_max=250000000 and applied the changes using sudo sysctl -p
/etc/sysctl.d/99-custom.conf. The the buffer size is resized, but the overflows and
underflows are yet occuring and the cpu usage is below 10%.
I am sending you the screenshots of my simulation console and hope that you
help me!
Thank you in advance!
Best regards,
Olivia Mammadova