Influence of noise of common oscillator in dual-mixer time-difference measurement system

Formulae are presented for the determination of the influence of the noise of the common oscillator in the dual-mixer time-difference (DMTD) measurement system. It is shown that this influence will be eliminated when the time difference between the zero crossings of the beats approaches zero no matter what kind of power spectral density the common oscillator signal provides. The formulae to calculate the influence of the common oscillator for different kinds of power-law density are presented. A synthesizer used as the common oscillator is also discussed.