A semi-automatic carrier noise analysis test equipment

A high-performance S-band carrier noise analyzer is described, designed for operation by test technicians in a production environment. Semi-automatic control of the instrumentation reduces the human element and uncertainty to a minimum, as well as decreases the testing time. The carrier noise analysis test equipment (CNATE) measures the noise in sidebands on pulsed and C.W. sources and amplifiers. It provides for four basic modes of operation in S-band: (1) amplitude noise measurements/absolute; (2) frequency noise measurements/absolute; (3) amplitude noise measurements/insertion; and (4) phase noise measurements/insertion. Performance results show that using an input power of 10 mW SSB, noise levels of 140 dB/Hz to 160 dB/Hz below carrier could be measured in the sideband frequency range of 50 Hz to 5 MHz for all modes except FM source. In the latter mode the threshold is thermal noise limited for sideband frequencies greater than 100 kHz; below this frequency it rises about 25 dB per decade, giving a typical threshold level of 90 dB/Hz below carrier at 100 Hz sideband frequency.