Noise in stages and in interstage couplings of various transistor circuits

The overall noise level and the spectral noise power density are calculated or the design of high-sensitivity low-noise transistor devices on the basis of the equivalent noise generator and gamma-parameters corresponding to the three fundamental transistor circuit configurations: common-emitter, common-collector, common-base. The equations are first solved exactly and then approximately. It is indicated that the approximate solution yields the sought noise characteristics with a degree of accuracy adequate for engineering purposes. The method of calculations is easily extended to combinations of transistor stages such a common-emitter/common-emitter pair or a common-emitter/common-collector pair.