Accession Number : AD0786558

Title :   Noise Properties of a VHF Power Amplifier Theory and Experiment.

Descriptive Note : Final rept. 19 Jan 72-20 May 74,


Personal Author(s) : Post,R. E. ; Choi,Won K. ; Hallock,D. B.

Report Date : JUN 1974

Pagination or Media Count : 75

Abstract : A study has been made to determine the mechanism of noise generation in vhf power amplifiers and oscillators in the 54- to 80-MHz range. Primary emphasis was placed on those amplifiers operating in the highly efficient Class D or switching mode whose instantaneous collector voltage is at or above the breakdown region. A primary result of the study is that the predominant source of output noise is avalanche multiplication in the collector-base region. A mathematical basis for predicting the static noise power has been developed, which shows good agreement with measurements made at 70 MHz on an amplifier covering the 54- to 80-MHz region with 40-watt output capability. Some special noise measurement test equipment was also developed during the study to facilitate accurate noise power measurements to within 5 percent away from the carrier frequency. Further work in this area is needed to correlate the dynamic noise power to transistor parameters. Improved techniques are also required to obtain parameters for the noise model with sufficient accuracy to characterize the avalanche process. (Author)

Descriptors :   *Power amplifiers, Very high frequency, Noise, Oscillators, Transistors, Avalanche diodes, Transistor amplifiers

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE