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. 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). 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. 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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