Despite the "digital revolution," the physical world remains analog. Modern systems rely on high-performance analog front-ends to interface with the environment.
To send data efficiently, it must be superimposed onto a carrier wave—a process known as modulation.
These circuits handle the conversion between baseband signals (the raw data) and passband signals (the high-frequency signal sent through the air). Modern systems utilize complex schemes like QAM (Quadrature Amplitude Modulation) to maximize data rates.