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Steve Markgraf Steve.Markgraf at student.hs-rm.deHi, On 07.07.2012 13:42, Francesco Gugliuzza wrote: > Hi Leif! Nice work, and I'm glad to hear my post inspired you, even > if > my code didn't work at all! Your code was changing settings of the RF- and IF-AGC, which do nothing more than modulating the AGC_RF and AGC_IF outputs of the RTL2832, which are connected to the GAIN0/GAIN1 inputs of the E4000. But since we're using the serial interface gain control mode, enabling the RF/IF-AGC won't have any effect, because the GAIN0/1 inputs are ignored. > I'm now setting 0x05 (0000 0101) instead of the original 0x25 (0010 > 0101) or your 0xd5 (1101 0101), to avoid setting unknown bits, and it > seems to have the same effect (I see an about 10 dB noise floor drop > when on minimum gain with no signal). That's also what I observed, clearing bit 5 is enough to disable the AGC. I also noticed that both DAGC gain registers (page 1, 0x12 and page 0, 0x17) have no effect once bit 5 in the settings register is cleared. The control logic still seems to operate though, which can be observed by reading register 0x05 in page 3. Regards, Steve