This file contains random notitions
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Sample rates between 301000 Hz and 900000 Hz (inclusive) are not supported.
They cause an invalid configuration of the RTL chip.
  rsamp_ratio = 28.8 MHz * 2**22 / sample_rate
  If bit 27 and bit 28 of rsamp_ratio are different, the RTL chip malfunctions.

The RTL chip has a configurable 32-tap FIR filter.
RTL-SDR currently configures it for cutoff at 1.2 MHz (2.4 MS/s).

Casual test of ADC errors:
 * DC offset in order of 1 code step
 * I/Q gain mismatch in order of 4%
 * I/Q phase mismatch in order of 1% of sample interval

With tuner in auto-gain mode, device autonomously switches between gain
settings during a run. The tuner gain seems to switch between ~ 24 dB
and ~ 34 dB without intermediate steps.

With RTL in AGC mode, the level of the digital sample stream is normalized
to -6 dBFS. Unknown whether this is an analog or digital gain stage.
Unknown whether AGC mode is coupled to Elonics IF gain or purely
a digital thing in the RTL chip.
Does this improve SNR or not?

Default settings in librtlsdr:
  Elonics LNA gain: when auto tuner gain: autonomous control with slow update
                    otherwise gain as configured via rtlsdr_set_tuner_gain
  Elonics mixer gain: autonomous control disabled,
                      gain depending on rtlsdr_set_tuner_gain
  Elonics IF linearity: optimize sensitivity (default), auto switch disabled
  Elonics IF gain: +6, +0, +0, +0, +9, +9 (non-standard mode)
  Elonics IF filters: matched to sample rate (note this may not be optimal)
  RTL AGC mode off


Local radio stations:
radio2      92600000  (good)
radio3      96800000  (good)
radio4      94300000  (bad)
qmusic     100700000  (medium)
radio538   102100000  (medium)
radio10    103800000  (bad)
radio west  89300000  (medium)