HI fellows, I was wondering if anybody has been trying to reach 8 Complex Msps over the USB 2.0 on the Tx path. While this has always been OK with old libusrp (and USRP 1) it appears to be no longer possible by means of UHD neither when trying to do that on USRP1 (a few underruns) nor on B100 (lots of overruns).
Everything appears instead fine on the Rx path Is there any workaround to this? ..or did I miss something? thanks everybody PS USB 3.0 seems to be capable enough for the 8 Msps. Is USB3.0 a requirement for 8 Msps on the B100? ____________________________________________________________B100 ./benchmark_rate --tx_rate 8e6 linux; GNU C++ version 4.6.1 20110908 (Red Hat 4.6.1-9); Boost_104600; UHD_003.004.000-325-g7e296167 Creating the usrp device with: ... -- USRP-B100 clock control: 10 -- r_counter: 2 -- a_counter: 0 -- b_counter: 20 -- prescaler: 8 -- vco_divider: 5 -- chan_divider: 5 -- vco_rate: 1600.000000MHz -- chan_rate: 320.000000MHz -- out_rate: 64.000000MHz -- Using Device: Single USRP: Device: B-Series Device Mboard 0: B100 (B-Hundo) RX Channel: 0 RX DSP: 0 RX Dboard: A RX Subdev: WBX RX v3 + Simple GDB TX Channel: 0 TX DSP: 0 TX Dboard: A TX Subdev: WBX TX v3 + Simple GDB Testing transmit rate 8.000000 Msps UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU Benchmark rate summary: Num received samples: 0 Num dropped samples: 0 Num overflows detected: 0 Num transmitted samples: 79931260 Num sequence errors: 0 Num underflows detected: 406 Done! ./benchmark_rate --tx_rate 8e6 --tx_otw sc16 linux; GNU C++ version 4.6.1 20110908 (Red Hat 4.6.1-9); Boost_104600; UHD_003.004.000-325-g7e296167 Creating the usrp device with: ... -- USRP-B100 clock control: 10 -- r_counter: 2 -- a_counter: 0 -- b_counter: 20 -- prescaler: 8 -- vco_divider: 5 -- chan_divider: 5 -- vco_rate: 1600.000000MHz -- chan_rate: 320.000000MHz -- out_rate: 64.000000MHz -- Using Device: Single USRP: Device: B-Series Device Mboard 0: B100 (B-Hundo) RX Channel: 0 RX DSP: 0 RX Dboard: A RX Subdev: WBX RX v3 + Simple GDB TX Channel: 0 TX DSP: 0 TX Dboard: A TX Subdev: WBX TX v3 + Simple GDB Testing transmit rate 8.000000 Msps UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU Benchmark rate summary: Num received samples: 0 Num dropped samples: 0 Num overflows detected: 0 Num transmitted samples: 79890620 Num sequence errors: 0 Num underflows detected: 696 Done! ____________________________________________________________USRP 1 ./benchmark_rate --tx_rate 8e6 --tx_otw sc16 linux; GNU C++ version 4.6.1 20110908 (Red Hat 4.6.1-9); Boost_104600; UHD_003.004.000-325-g7e296167 *** Warning! *** Benchmark results will be inaccurate on USRP1 due to insufficient features. Creating the usrp device with: ... -- Opening a USRP1 device... -- Using FPGA clock rate of 64.000000MHz... Using Device: Single USRP: Device: USRP1 Device Mboard 0: USRP1 (Classic) RX Channel: 0 RX DSP: 0 RX Dboard: B RX Subdev: WBX RX v2 + Simple GDB TX Channel: 0 TX DSP: 0 TX Dboard: B TX Subdev: WBX TX v2 + Simple GDB Testing transmit rate 8.000000 Msps UUUUU Benchmark rate summary: Num received samples: 0 Num dropped samples: 0 Num overflows detected: 0 Num transmitted samples: 80022656 Num sequence errors: 0 Num underflows detected: 5 Done! ____________________________________________________________everything fine with 8bit samples ./benchmark_rate --tx_rate 8e6 --tx_otw sc8 linux; GNU C++ version 4.6.1 20110908 (Red Hat 4.6.1-9); Boost_104600; UHD_003.004.000-325-g7e296167 -- Loading firmware image: /usr/share/uhd/images/usrp_b100_fw.ihx... done Creating the usrp device with: ... -- USRP-B100 clock control: 10 -- r_counter: 2 -- a_counter: 0 -- b_counter: 20 -- prescaler: 8 -- vco_divider: 5 -- chan_divider: 5 -- vco_rate: 1600.000000MHz -- chan_rate: 320.000000MHz -- out_rate: 64.000000MHz -- -- Loading FPGA image: /usr/share/uhd/images/usrp_b100_fpga.bin... done Using Device: Single USRP: Device: B-Series Device Mboard 0: B100 (B-Hundo) RX Channel: 0 RX DSP: 0 RX Dboard: A RX Subdev: WBX RX v3 + Simple GDB TX Channel: 0 TX DSP: 0 TX Dboard: A TX Subdev: WBX TX v3 + Simple GDB Testing transmit rate 8.000000 Msps Benchmark rate summary: Num received samples: 0 Num dropped samples: 0 Num overflows detected: 0 Num transmitted samples: 80053688 Num sequence errors: 0 Num underflows detected: 0 Done! -- Vincenzo Pellegrini http://www.youtube.com/user/wwvince1
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