Experimental tests of the theory of an amplitude-limited correlation detector

A sensitive correlation detector has been constructed in which the input signal and noise voltages are amplitude-limited. The correlator is described and experimental results are given in support of the theory. A method of analysing the data from the correlator to obtain the maximum output signal/noise ratio is discussed for the case where the signal and noise voltages depend on slowly varying functions of time. Particular reference is made to the analysis of data from observations with the stellar intensity interferometer for which the correlator was specifically designed. It is concluded that the dual-channel amplitude-limited correlator is stable and that it can be used to obtain accurate, meaningful and linear results despite the non-linear operations involved.