In attempting to understand how I can extract the phase difference between two RTL-SDRs, I’ve encountered a number of “frequencies”:
The original signal’s antnna-detected Radio Frequency.
The Intermediate Frequency.
The Local Oscillator Frequency.
The RTL-SDR’s shared clock Frequency.
The The A/D sampling Frequency.
The Baseband “0 Hz” Frequency.
The Decimation Frequency.
The demodulated (sometimes audio) Frequency.
Some of these frequencies are unconditionally identical (ie: they are synonymous by definition). Some are conditionally identical. Some depend on others. Each has associated phase.
In the case of Direction of Arrival, the equivalent of phase difference seen by different antennas must be, somehow, calculated from one or more of the above “frequencies”.
Is there a single page that disentangles these “frequencies” showing their relationships and how they contribute to the calculation of phase differences seen at the antennas?