LONG LIFE RF-POWER TRANSISTORS (LOW NOISE).

The objective of the work was to determine the inter-relationships between the noise power output from transistors in broadband power output amplifier stages and the transistor characteristics such that noise generating mechanisms are identified. A complete instrumentation system was designed and set up to allow measurements to be made of high level sideband noise. That is, sideband noise associated with a carrier signal emerging from a transistorized 50 watt RF power amplifier stage. This instrumentation system consisted of a frequency stable low noise driver source, amplifier test fixture, and a noise detection and measuring system. Of particular importance in the noise measuring system is a carrier suppression filter. This filter allows measurements to be made to within 50 KHz of the carrier frequency without the detection system being desensitized due to overloading by high level signals. Data are presented on the measuring system sensitivity, power gain performance of the test transistors and sideband noise measurements. Low level noise source studies have also been conducted in order to identify correlation between these noise sources and the high level noise sidebands. In particular, lf noise and background noise measurements were made. Author