Modeling the noise figure of an acousto-optic receiver

By defining the processing gain of an acousto-optic receiver as the ratio of the signal-to-noise ratio at the output of the detector to the signal-to-noise ratio of the intermediate-frequency input, one can model a noise figure for the acousto-optic receiver. The noise figure has a minimum of 0 dB and depends on the ratio of the noise power (internal to the acousto-optic cell) to the intermediate-frequency input noise power multiplied by the frequency and the spatially dependent exponential factor.