How are the effects of DC mitigated in GNU radio? For example, if I use the uhd_fft.py to just scan the spectrum, I do not see any DC spike at the centre frequency. When I looked at the code, it has :
r = self.u.set_center_freq(target_freq, 0)
So I assume, it does not use the advanced tuning feature of UHD. Is this correct? How, in this case is there no DC spike seen at the centre frequency? I am trying to code a scanning system that goes through the whole frequency band of my RFX2400 dboard and at each center frequency, I grab a packet from the air and apply an FFT to check for possible interferers etc. But I am ending up with a spike at every centre frequency iteration. I have used the two stage advanced tuning to try and push the DC leakage out of my band of interest but I see no difference. I still get that single spike. (I am using the UHD library and not GNU Radio)