High frequency noise figure — A function of fα or fT?

Author

Thornton, J.W.

Author_Institution

Philco Corporation, Lansdale Division, Lansdale, Penna

Issue

fYear

1963

fDate

5/1/1963 12:00:00 AM

Firstpage

Lastpage

Abstract

There has been some question in the past as to whether fα or fT should be used as the frequency criterion in determining transistor high frequency noise figure. This report is based on the following equation for noise figure as derived by Nielsen:¹ $F = 1 + {r_{b}^{\\prime } \\over r_{g}} + {r_{e} \\over 2r_{g}} + {{({r}_g+{r}_{b}^{\\prime } + {r}_e)^2} \\over {2r_{e}, r_g , \\beta _o}} \\left [1 + {(f/f_a)^2 \\over 1-\\alpha _o}\\right]. \\eqno{\\hbox {(1)}}$ Results show rather conclusively that fα should be used and not fT, for the frequency range from approximately 40 to 300 mc. These results apply specifically to the diffused base 2N1742 transistor. Conclusions have been drawn by comparing (1) the degree to which theoretical fα-noise figure correlates with measured noise figure to (2) the degree to which theoretical fT-noise figure correlates with measured noise figure

fLanguage

English

Journal_Title

Broadcast and Television Receivers, IEEE Transactions on

Publisher

ieee

ISSN

0018-9308

Type

jour

DOI

10.1109/TBTR1.1963.6312106

Filename

6312106

Link To Document

https://search.isc.ac/dl/search/defaultta.aspx?DTC=49&DC=1293135