On Thu, Jul 30, 2015 at 6:30 PM, John Garrick <[email protected]> wrote:
> Hi all, > I want to transmit the data between two USRP's and make them communicate > with each other. But I guess the packets are not being received > properly.. > My USRP daughterboard model is XCVR2450. When I am running > ./benchmark_tx.py -f 2.435G, it is starting to transmit the packets but > a small error occured given below, > > linux; GNU C++ version 4.8.4; Boost_105500; > UHD_003.009.git-144-g407e3086 > > Using Volk machine: avx_64_mmx > -- Opening a USRP1 device... > -- Using FPGA clock rate of 64.000000MHz... > > No gain specified. > Setting gain to 7.500000 (from [-20.000000, 35.000000]) > > UHD Warning: > The hardware does not support the requested TX sample rate: > Target sample rate: 0.050000 MSps > Actual sample rate: 0.250000 MSps > > Symbol Rate: 25000.000000 > Requested sps: 2.000000 > Given sample rate: 250000.000000 > Actual sps for rate: 10.000000 > > Requested sample rate: 50000.000000 > Actual sample rate: 250000.000000 > > ..............................................................................................U...............................................................terminate > called after throwing an instance of 'uhd::runtime_error' > what(): RuntimeError: usb tx2 transfer status: 1 > Aborted (core dumped). > > > But towards the receiver side, I gave the command ./benchmark_rx.py -f > 2.435GG,it has shown the result given below with n_right=0. > > > linux; GNU C++ version 4.8.4; Boost_105500; > UHD_003.009.git-144-g407e3086 > > Using Volk machine: avx_64_mmx > -- Opening a USRP1 device... > -- Using FPGA clock rate of 64.000000MHz... > > No gain specified. > Setting gain to 56.250000 (from [0.000000, 112.500000]) > > UHD Warning: > The hardware does not support the requested RX sample rate: > Target sample rate: 0.050000 MSps > Actual sample rate: 0.250000 MSps > > Symbol Rate: 25000.000000 > Requested sps: 2.000000 > Given sample rate: 250000.000000 > Actual sps for rate: 10.000000 > > Requested sample rate: 50000.000000 > Actual sample rate: 250000.000000 > ok = False pktno = 53034 n_rcvd = 1 n_right = 0 > ok = False pktno = 24 n_rcvd = 2 n_right = 0 > ok = False pktno = 35 n_rcvd = 3 n_right = 0 > ok = False pktno = 44 n_rcvd = 4 n_right = 0 > ok = False pktno = 46 n_rcvd = 5 n_right = 0 > ok = False pktno = 46 n_rcvd = 6 n_right = 0 > ok = False pktno = 3872 n_rcvd = 7 n_right = 0 > ok = False pktno = 12304 n_rcvd = 8 n_right = 0 > ok = False pktno = 49 n_rcvd = 9 n_right = 0 > ok = False pktno = 50 n_rcvd = 10 n_right = 0 > ok = False pktno = 54 n_rcvd = 11 n_right = 0 > ok = False pktno = 200 n_rcvd = 12 n_right = 0 > ok = False pktno = 63 n_rcvd = 13 n_right = 0 > > My USRP can access in the range of 2.4GHZ to 5GHZ. Please advice as to > what I can do. Thanks > > Regards, > John > John, There's lots of things that can go wrong here. You didn't set the gains or transmit amplitude. Do you know if you have a significant frequency offset between your two radios? You might need to adjust that. The fact that you are getting "ok = False" means that the receiver saw a packet, but there were too many errors and the CRC check failed. Note there is no FEC applied to the benchmark scripts. So this could be due to low SNR, a bad channel, or, frankly, many other possibilities. Tom
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