On 06/27/2018 11:31 AM, Rob Kossler via USRP-users wrote:
> Hi,
> I am getting some unexpected behavior from my N310 using the example
> 'tx_waveforms' utility and stock FPGA image using 'rfnoc-devel'.  If I
> simply switch to 'maint', things behave as expected.  Here are the issues...
> 
>  1. With 'rfnoc-devel', it is necessary for me to specify a subdev spec
>     (A:0 A:1 B:0 B:1) in order to access all 4 channels. Otherwise, I
>     can only see 2 channels. This is not a big problem, but wanted to
>     mention it because it appears that the default subdev spec is not
>     correct.  With 'maint', all 4 channels are available with default
>     subdev spec.

Rob,

this is now fixed (on master, which has all the RFNoC stuff).

>  2. With 'rfnoc-devel', I get unexpected TX output power levels on the
>     various channels when using the example program 'tx_waveforms' with
>     the 'constant' waveform which produces a single tone at the carrier
>     frequency (see table below).

Thanks for bringing this up, also, thanks for providing the graph in the
other thread. On master, this is now fixed.

>  3. With 'rfnoc-devel', I can only run 1 channel at a time. If I specify
>     more than one channel (e.g., '--channels=0,1'), I get an error
>     message that the PPS is not detected (even though using 'internal')
>     and the example program crashes.  With 'maint', multiple channels
>     work fine.

Even on the same commit hash, I don't see that issue. Can you please
check current HEAD of master again? I'd really like to get you unstuck
here, but I don't see a clear path forward.
It's very interesting this is not an issue on maint.

-- M


> 
> The table below shows the measured RF power levels (dBm) for a single
> tone output at 2400 MHz.  The tx_gain setting was 45 (20 dB below
> maximum) and there was about 31dB external attenuation.  So, for a
> measured power of -28 dBm, this implies that the maximum usrp output
> power is +23dBm (-28 + 20 + 31).
> 
> Channel    maint    rfnoc-devel
>    0       -27.8    -27.8* (some trials ~-67)
>    1       -27.9    -66.6* (some trials ~-27)
>    2       -27.6    -39.9* (some trials ~-67)
>    3       -27.6    -54.6* (consistent)
> 
> Details:
> 
>   * maint hash: ad6b0935
>   * rfnoc-devel hash: 1f8463cc
>   * command line: tx_waveforms --rate 20e6 --freq 2400e6 --gain 45
>     --channels <ch>
>   * os: ubuntu 16.04
> 
> Thank you.
> Rob
> 
> 
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