Radar receiver noise ratio detector

Claim 1

A ratio detector to discriminate between signal-plus noise input and noise-only input to a radar receiver said receiver including a sum, a difference signal generating means which generates an asimuth difference signal, an elevation difference signal and a summation signal of the asimuth and elevation signal, said detector comprising in combination: a. a first envelope detector; b. a second envelope detector; c. a third envelope detector wherein said summation signal is applied to the input of said first envelope detector; said asimuth signal is applied to said second envelope detector and said elevation signal is applied to said third envelope detector; d. said first envelope detector generating an output signal to the input of a first low pass filtering means; e. said second envelope detector generating an output signal to the input of a second low pass filtering means; f. said third envelope detector generating an output signal to the low pass filtering means wherein the output signal from said first filter is applied to a first adding means and a second adding means wherein the output signal from a said second filter is applied to a first multiplication apparatus and the output of said third filter is applied to a second multiplication apparatus; g. said first multiplication apparatus generating an output signal which is applied to an input of said first adding means; h. said second multiplication apparatus generating an output signal from said second multiplication apparatus; i. said first adding means subtracting said first multiplication apparatus output signal from the first low pass filter output signal to generate a first remainder output signal from said first adding means; and j. said second adding means subtracting said second multiplIcation apparatus output signal from the first low pass filter output signal to generate a second remainder output signal from said second adding means.