In one aspect, this document provides an implementation of a system for characterizing an oscillator. This system includes an input port that receives an oscillation signal from an oscillator under test; an input port signal splitter that splits the received oscillation signal into a first oscillation signal and a second oscillation signal; a first photonic signal processing branch circuit that processes the first oscillation signal to produce a first branch output signal; a second photonic signal processing branch circuit that processes the second oscillation signal to produce a second branch output signal; a dual channel signal analyzer that receives the first and second branch output signals to measure noise in the received oscillation signal; and a computer controller that controls the first and second photonic signal processing branch circuits and the dual channel signal analyzer to control measurements of the noise in the received oscillation signal.