METHOD AND APPARATUS FOR SETTING THE SIGNAL-TO-NOISE RATIO OF A CARRIER WAVE

摘要

12 A signal source which provides a carrier signal having a precisely set signal-to-noise ratio is provided. The carrier signal and its sideband noise components are attenuated below the equivalent thermal noise floor of an attenuator. The attenuated carrier signal and the equivalent thermal noise floor are then amplified in an amplifier having a known noise figure to produce a composite carrier signal having a usable power level and a precisely known signal-to-noise ratio. Since the equivalent thermal noise floor is a function only of temperature, the desired carrier signal-to-noise ratio may he set by setting the power level of the carrier signal and knowing the noise figure of the amplifier. Case 187021