27 Feb
2017
27 Feb
'17
3:38 p.m.
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