Difference between varactor modulator and reactance modulator?

A varactor modulator uses a varactor diode, which changes its capacitance with varying voltage, to modulate signals, typically in frequency modulation applications. In contrast, a reactance modulator alters the reactance of a circuit using various components (like capacitors or inductors) to achieve modulation, often in amplitude modulation schemes. While both techniques modify the reactive properties of a circuit to achieve modulation, the varactor modulator specifically relies on the tunable capacitance of the varactor diode for its operation.