An investigation of the up-converter parametric amplifier
Burrus, C. S. (Charles Sidney)
Wischmeyer, C. R.
Master of Science
A model of the up-converter parametric amplifier is developed in order to derive expressions for admittance, gain, bandwidth, and noise figure. The expressions derived are presented in such a way as to show a good analogy to the standard coupled circuit. This allows use of the concepts of coefficient of coupling, critical coupling, and stagger-tuning and their effects upon bandwidth. it is shown that the gain of the amplifier is equal to the ratio of output frequency to input frequency and is constant, independent of matching, resonance, or pump level. The derived expression for noise figure indicates that the principal noise source is the input tank and that heavy loading of both tanks improves the noise figure. The results of experimental tests are used to verify the relations derived and show the limitations of the model and the amplifier. Also the possibility of using the experimental circuit as a practical low-noise amplifier is examined.