Phase principle for detecting narrow-band Gaussian signals

This paper describes a phase principle for detecting a weak, narrow-band Gaussian signal in the presence of receiver noise. The phase principle leads to a phase detector which performs 2.5 db worse than the time-honored square-law detector when gain fluctuations are negligible. However, when gain fluctuations are significant the phase detector can perform better than the square-law detector. The phase principle can be implemented by using radio interferometer type receivers or mono-pulse radar-type receivers.