MINIMUM NOISE TEMPERATURE OF A PARAMETRIC AMPLIFIER,
Abstract
The relation between noise temperature, pump power, and the measurable parameters of the nonlinear reactance in a parametric amplifier are derived. For a variable-capacitance amplifier, the attainable minimum noise temperature and the corresponding pump power are expressed in terms of the physical temperature of the variable capacitance, its Q, its law of capacitance variation, and the frequencies involved. The conditions under which contributions from the circuit losses are negligible are pointed out. The basic results of this analysis are: (1) The minimum attainable noise temperature is determined by the variable-capacitance parameters; (2) An optimum value of the ratio of idler to signal frequency for minimum noise temperature exists under certain conditions. This optimum does not necessarily correspond to an infinite value of this ratio; (3) Abrupt semiconductor junctions appear to have some advantage over diffused junctions as variable-capacitance elements for low-noise parametric amplifiers. Experimental results obtained at S-band have substantiated the above analysis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1959
- Accession Number
- AD0607841
Entities
People
- R. C. Knechtli
- R. D. Weglein