Passive dynamic method & measurements of compressed amplifiers to determine amplitude noise effects on system noise performance

Newer systems require improved noise performance in order to detect and track targets at great distances in difficult clutter environments. Typically, phase noise is an area that is closely watched as a main contributor to overall system noise performance. Amplitude noise is often treated as a second order effect because systems are often operated in amplitude compression during transmits to maximize the effective radiated power. This amplitude compression, in effect, will strip off most of the amplitude noise generated. Advances in phase noise performance continue to improve to the degree such that corruption due to other noise contributors may degrade overall system phase noise performance. This paper reflects a potential method of measuring transmit modules in a passive-dynamic mode to account for this phenomenon. Total noise can now considered at the output as a function of drive level and total input noise. Measured data from a module will illustrate the technique.