This article studes gain and phase characteristics of a parametric amplifier with the emphasis on phase characteristic.In this paper influence of pumping frequency and power variantion on gain and phase characteristic of the parametric amplifier is characterized by a mathematical model of all differential multiple argument function. And variation rates of phase of parametric amplifier with pumping frequency and power are defined respectively as θ’f p and θ’p. Thus influence of pumping frequency and power on phase characteristic of the parametric amplifier can be separated and studied individually

analysti-cal result

formulae and experimental methods are obtained.These formulae may be used to estimate both systematic phase error and random phase error of parametric amplifier.In this article

an experimental model of three parametric amplifiers with one pumping sourse is presented. It’s gain and phase characteristic of signal frequency

influence of pumping frequency and power on gain and phase characteristic of the parametric amplifier

relative phase shift difference between two channals are also given.