Ham Radio Style Frequency Translation & Zoom
Frequency Translation: Mixing input signal with a local oscillator (carrier) creates sum and difference frequencies. The difference frequency centers our signal of interest around 0 Hz (baseband).
Low-Pass Filtering: Removes the high-frequency sum components and noise outside our bandwidth of interest.
Zoom FFT: Taking FFT of the filtered baseband signal gives high-resolution view of frequencies around the carrier.
Applications: Software Defined Radio (SDR), spectrum analyzers, communication receivers.