[USRP-users] Rx/Tx Loopback

Rob Kossler rkossler at nd.edu
Thu Apr 2 10:28:00 EDT 2015


On Wed, Apr 1, 2015 at 11:45 PM, Marcus D. Leech <mleech at ripnet.com> wrote:

>  On 04/01/2015 11:41 PM, Rob Kossler wrote:
>
>
>
>>
>>   Yes, those are the sync options.  Since there is only one device, I
> only selected "unknown PPS" for one of the two streamers.  Is that correct?
>  Rob
>
> That would be correct for a device that had 1PPS.  I don't recall whether
> X3xx has a "fake" internal 1PPS signal or not.  Since this is a single
> device
>   at this point, just choose "don't sync" for both of them.
>
>
>
I tried "don't sync" for both as well as putting constant multiply blocks
in between the source / sink.  Neither seems to fix my "Late" issue.
However, if I exit GRC and simply run benchmark_rate in full duplex, it has
no issues even at higher sample rates.

Attached are 3 files: the modified GRC flowgraph as well as two text files
showing the results obtained when running this flowgraph from GRC as
compared to running benchmark_rate.  The flowgraph sample rate is 1 MS/s
while the benchmark_rate is running at 10 MS/s (BTW, it also runs fine at
1MS/s).

Rob
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crosshair at crosshair-HP-Z440:~$ benchmark_rate --tx_rate=10e6 --rx_rate=10e6 --channels="0,1"
linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.002-131-gb850dfb5


Creating the usrp device with: ...
-- X300 initialization sequence...
-- Determining maximum frame size... 8000 bytes.
-- Setup basic communication...
-- Loading values from EEPROM...
-- Setup RF frontend clocking...
-- Radio 1x clock:200
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Initializing clock and time using internal sources... done
Using Device: Single USRP:
  Device: X-Series Device
  Mboard 0: X310
  RX Channel: 0
    RX DSP: 0
    RX Dboard: A
    RX Subdev: CBX-120 RX
  RX Channel: 1
    RX DSP: 1
    RX Dboard: B
    RX Subdev: CBX-120 RX
  TX Channel: 0
    TX DSP: 0
    TX Dboard: A
    TX Subdev: CBX-120 TX
  TX Channel: 1
    TX DSP: 1
    TX Dboard: B
    TX Subdev: CBX-120 TX

Testing receive rate 10.000000 Msps on 2 channels
Testing transmit rate 10.000000 Msps on 2 channels

Benchmark rate summary:
  Num received samples:    200023152
  Num dropped samples:     0
  Num overflows detected:  0
  Num transmitted samples: 200230736
  Num sequence errors:     0
  Num underflows detected: 0


Done!

crosshair at crosshair-HP-Z440:~$ 

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<<< Welcome to GNU Radio Companion v3.7.6.1-128-g8a3ad1a5 >>>

<<DELETED CONTENT>>

Generating: "/home/crosshair/Documents/gnuradio/rx_tx_loopback.py"

Executing: "/home/crosshair/Documents/gnuradio/rx_tx_loopback.py"

linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.002-131-gb850dfb5

-- X300 initialization sequence...
-- Determining maximum frame size... 8000 bytes.
-- Setup basic communication...
-- Loading values from EEPROM...
-- Setup RF frontend clocking...
-- Radio 1x clock:200
-- Initialize Radio control...
-- Performing register loopback test... pass
-- Performing register loopback test... pass
-- Initializing clock and time using internal sources... done
-- Tune Request: 2412.000000 MHz
--   The RF LO does not support the requested frequency:
--     Requested LO Frequency: 2412.000000 MHz
--     RF LO Result: 2411.999389 MHz
--   Attempted to use the DSP to reach the requested frequency:
--     Desired DSP Frequency: -0.000611 MHz
--     DSP Result: -0.000610 MHz
--   Successfully tuned to 2412.000000 MHz
-- 
-- Tune Request: 2412.000000 MHz
--   The RF LO does not support the requested frequency:
--     Requested LO Frequency: 2412.000000 MHz
--     RF LO Result: 2411.999389 MHz
--   Attempted to use the DSP to reach the requested frequency:
--     Desired DSP Frequency: -0.000611 MHz
--     DSP Result: -0.000610 MHz
--   Successfully tuned to 2412.000000 MHz
-- 
-- Tune Request: 2412.000000 MHz
--   The RF LO does not support the requested frequency:
--     Requested LO Frequency: 2412.000000 MHz
--     RF LO Result: 2411.999389 MHz
--   Attempted to use the DSP to reach the requested frequency:
--     Desired DSP Frequency: 0.000611 MHz
--     DSP Result: 0.000610 MHz
--   Successfully tuned to 2412.000000 MHz
-- 
-- Tune Request: 2412.000000 MHz
--   The RF LO does not support the requested frequency:
--     Requested LO Frequency: 2412.000000 MHz
--     RF LO Result: 2411.999389 MHz
--   Attempted to use the DSP to reach the requested frequency:
--     Desired DSP Frequency: 0.000611 MHz
--     DSP Result: 0.000610 MHz
--   Successfully tuned to 2412.000000 MHz
-- 
Using Volk machine: avx_64_mmx
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL


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