RTLSDR IQ imbalance ???

Lucas Teske lucas at teske.net.br
Mon Feb 27 14:38:28 UTC 2017


That doesn't look an IQ Imbalance but a DC Offset. But that depends a 
lot of the tuner you use.

I develop some softwares using rtlsdr, and the newest dongles with 
R820T2 dongle doesn't have IQ Imbalance or DC Spike issues by default.


Em 27/02/2017 10:30, a c escreveu:
> Hello,
> I use RTL-FM on a raspberry pi3. I notice practically always the
> presence of a weak carrier accompanying the emission received in AM
> mode and interferences in NFM mode. When i use rtl-tcp and sdr# or
> sdrconsole the demodulation is perfect. I assume that IQ amplitude
> phase correction is involved. I saw in the source of rtlsdr:
> IQ estimation / compensation (en_iq_comp, en_iq_est) * /
> Rtlsdr_demod_write_reg (dev, 1, 0xb1, 0x1b, 1);
> I suppose we use an internal chipset function? Is this function good
> enough? I did not find anything about it in RTL-FM but I'm not a
> specialist. Is an improvement possible?
> Regards,
> Arnaud



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