Determination of Transistor Performance Characteristics at VHF

The important performance characteristics of transistors as amplifiers at vhf are matched power gain, noise factor, roll-off characteristic, and terminal impedances. The matched power gain represents power gain occurring when both the input and output impedances of the transistor are conjugately matched. The noise factor of a transistor amplifier is measured with conjugate matching from a noise diode to the final load. The power gain roll-off is the matched power gain as a function of frequency. It allows power gain prediction over a wide-frequency band from a single-frequency measurement. Terminal impedances refer to the input and output impedance of a transistor. Each terminal impedance is measured with the other conjugately matched.