The results presented in this paper may be classified into three categories. First, there is derived the characteristics of gain, bandwidth, and figure of merit of a non-degenerative parametric amplifier of both fundamental and sub-harmonic pumping; and the comparison between them is carried out in substantial detail. Second, there is devised an analytical method for determining the harmonic contents of the capacitance of a nonlinear semiconductor diode, which is negatively biased and is under the action of a strong high frequency pumping voltage. The magnitudes of bias and pumping voltage are thus found quantitatively. Also, the stability requirements for pumping amplitude and pumping frequency are discussed. Third, the noise figure of a parametric amplifier itself and the effective noise figure of the amplifier loaded with a noisy second stage, which may be a frequency converter, are derived. Factors such as diode loss, match, and the bandwidth ratio of the signal to the idler circuit are all considered in the derivations so as to make the results with greater importance for practical applications. Finally, a numerical example is given to show the utility of the results presented in this paper and to illustrate a possible design procedure of a non-degenerative parametric amplifier.