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[Discuss-gnuradio] gnuradio transmission delay
From: |
Phelps Williams |
Subject: |
[Discuss-gnuradio] gnuradio transmission delay |
Date: |
Wed, 13 Jun 2012 17:15:04 -0700 |
I have a simple bpsk transmitter setup with a custom udp source block
which outputs a fixed pattern if no data is available from the socket.
I have instrumented the block to indicate when data is read from the
socket inside of work().
My radio looks like this:
Custom UDP Source -> DPSK Mod (DBPSK, 10 samp/sym) -> Multiply Const
(0.3) -> UHD: USRP Sink
My sample rate is 1e6.
I can tell from my instrumented UDP Source that udp traffic is handled
by work and passed on almost immediately. However I can tell from
both monitoring the spectrum and the receiver output on the other side
that the data takes between 7 and 10 seconds before I see the expected
output from the N200. I thought this could be improved by reducing
the maximum socket buffer size (sudo sysctl -w
net.core.wmem_max=5000000) but that didn't seem to make a difference.
I went as low as wmem_max=10000 with no difference in delay. My goal
is to get the total delay to < 1sec.
What else could be adding delay to my transmission path? Are there
other buffers I can tweak? Where else should I be looking?
-Phelps
- [Discuss-gnuradio] gnuradio transmission delay,
Phelps Williams <=
Re: [Discuss-gnuradio] gnuradio transmission delay, Rick Graham, 2012/06/17