Transistor noise at high injection levels

Abstract
Measurements of transistor noise at high injection levels are compared with the predictions made by the low-level injection theory, The noise is represented by an emf eein series with the emitter and a current generator i in parallel with the collector: eeis split into a part ee' fully correlated withiand a part ee" uncorrelated withi. The measured values of\bar{i^{2}}usually agree very well with theory, even at high currents; this indicates that the low-level injection theory of\bar{i^{2}}remains correct at high injection levels. The measurements of\bar{e_{e}^{"2}, though inaccurate, seem to indicate that the predictions made by the low-level injection theory are approximately correct at high injection levels. The measurements of the cross correlation\bar{e_{e}i^{*}}indicate a large discrepancy with the low-level injection theory. The theory predicts that\bar{e_{e}i^{*}}is quite small at low frequency and is mainly imaginary at high frequencies. The measurements indicate that\bar{e_{e}i^{*}}is quite large at low frequencies and that its real part is larger than the imaginary part at high frequencies. The fact that\bar{e_{e}i^{2}}varies as\sqrt{I_{E}}, so that it approaches zero at low currents, indicates that it is a high-level injection effect.

This publication has 0 references indexed in Scilit: