RX/TX calibration using the RLT-SDR
Posted: Sat Jan 19, 2019 11:52 am
Hi,
I use RTL-SDR as a spectrum analyzer for TX calibration, using oscmocom_siggen.
I managed to get DC spike and IQ quite low - what to do with the results I got in osmocom_siggen? I am playing with gnuradio companion - as for now I split IQ and "add const" for DC offset and then I use block of "IQ bal fix" to implement IQ corr values - is that correct approach? Can I apply this somehow though bladeRF-cli to skip additional blocks in gnuradio?
Are these values in bladerf-cli direct DAC settings (ie. the full swing of DAC is +/- 2048)? In the gnuradio DC offset example the step is set to 1.0/2048.0 so I'd need to convert that back if it's the case.
thanks,
best regards
I use RTL-SDR as a spectrum analyzer for TX calibration, using oscmocom_siggen.
I managed to get DC spike and IQ quite low - what to do with the results I got in osmocom_siggen? I am playing with gnuradio companion - as for now I split IQ and "add const" for DC offset and then I use block of "IQ bal fix" to implement IQ corr values - is that correct approach? Can I apply this somehow though bladeRF-cli to skip additional blocks in gnuradio?
bladeRF> cal lms
LPF tuning module: 23
TX LPF I filter: 30
TX LPF Q filter: 39
RX LPF I filter: 30
RX LPF Q filter: 33
RX VGA2 DC reference module: 25
RX VGA2 stage 1, I channel: 29
RX VGA2 stage 1, Q channel: 37
RX VGA2 stage 2, I channel: 41
RX VGA2 stage 2, Q channel: 25
Are these values in bladerf-cli direct DAC settings (ie. the full swing of DAC is +/- 2048)? In the gnuradio DC offset example the step is set to 1.0/2048.0 so I'd need to convert that back if it's the case.
thanks,
best regards