[USRP-users] B210 simultaneous Tx and Rx at 32 MS/s

Joan Olmos olmos at tsc.upc.edu
Tue Nov 28 18:11:56 EST 2017


Hi,
I'm trying to transmit and receive simultaneously using B210 in single 
channel mode. The sampling rate for both Tx and Rx is 32 Msamples/s.

I have a recent desktop computer with USB 3 running Debian. The UHD 
version is 3.9 LTS. The Tx streamer is started first and then the Rx 
streamer (both have their own thread).

The problem is that Tx seems to work properly but the first time 
"uhd_rx_streamer_recv" function is called it returns immediately (with 
no samples) and in next call it never returns.

I'm using USRP auto setup of master clock rate. It works if I reduce the 
sampling rate to 16MS/s.

Which can be the problem?
Thanks!
These are my logs at start-up:

Creating USRP with args "type=b200,  num_recv_frames=512, 
num_send_frames=512"...
-- Detected Device: B210
-- Operating over USB 3.
-- Detecting internal GPSDO.... Found an internal GPSDO: GPSTCXO , 
Firmware Rev 0.929a
-- Initialize CODEC control...
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Performing CODEC loopback test... pass
-- Performing CODEC loopback test... pass
-- Asking for clock rate 16.000000 MHz...
-- Actually got clock rate 16.000000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
-- Setting master clock rate selection to 'automatic'.
num. Rx channels reported by usrp: 2
num. Tx channels reported by usrp: 2
Subdevice Specification:
     Channel 0: Daughterboard A, Subdevice A
     Channel 1: Daughterboard A, Subdevice B

Subdevice Specification:
     Channel 0: Daughterboard A, Subdevice A
     Channel 1: Daughterboard A, Subdevice B

Device name: wicomtec-1 (30CD3EC)
Clock source reported by usrp: internal
--     1) catch time transition at pps edge
--     2) set times next pps (synchronously)
Corrected PC clock mismatch of: +1511908607310 milliseconds
Current Time reported by USRP: 1.001673 seconds
Current Time reported by PC: 1.001000 seconds
Normalized_rx_gain for channel 0 = 0.000000
Normalized_rx_gain for channel 0 = 0.000000
Setting Rate: 32000000.000000...
-- Asking for clock rate 32.000000 MHz...
-- Actually got clock rate 32.000000 MHz.
-- Performing timer loopback test... pass
-- Performing timer loopback test... pass
Actual Rate Rx(0): 32000000.000000...
Actual Rate Tx(0): 32000000.000000...
Actual Master clock rate: 32000000.000000

wire packet size: 2044 complex samples/packet, k: 1566
Setting frequencies: Rx: 2414.000000, Tx: 2414.000000 MHz...
Target RF frequency, clipped to be within system range: 2414000000.000000
Target RF frequency, including RF FE offset: 2414000000.000000
Frequency to which RF LO is actually tuned: 2413999999.761581
Frequency the CORDIC must adjust the RF: -0.238419
Frequency to which the CORDIC in the DSP actually tuned: -0.238419
Actual frequency Rx(0): 2414.000000 MHz...
Actual frequency Tx(0): 2414.000000 MHz...
Setting RX Gain: 50.000000 dB...
Antenna reported by usrp for RX channel 0: RX2
Actual Rx(0) Gain: 50.000000...
Rx: stream_args.cpu_format = fc32
Rx: stream_args.otw_format = sc16
Rx: stream_args.args = spp=2044
Rx: stream_args.channel_list = 0, 1
Rx: stream_args.n_channels = 1
max complex samps per wire packet = 2044
Available sensors:
temp
rssi
lo_locked
Checking RX: LO: locked ...
Rx buffer size in samples: 3200904
Setting TX Gain: 50.000000 dB...
Antenna reported by usrp for TX channel 0: TX/RX
Actual TX Gain: 50.000000...
Tx: stream_args.cpu_format = fc32
Tx: stream_args.otw_format = sc16
Tx: stream_args.args = spp=2044
Tx: stream_args.channel_list = 0, 1
Tx: stream_args.n_channels = 1
max complex samps per wire packet = 2044
Available sensors:
temp
lo_locked
Checking TX: LO: locked ...
Tx buffer size in samples: 3200904
configusrp: Success

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