Digital pulse detector circuit having selectable false alarm rate

DETAILED DESCRIPTION A method and apparatus is disclosed for detecting a repeated pulse in an input signal in which the input signal is included within a noisy environment.
The method samples the input signal during sequential time slots in a repeated time frame to produce a sequence of input samples.
A plurality of mathematically processed samples have been previously stored in a memory wherein each processed sample corresponds to one of the time slots within the time frame.
Each of the input samples when received is mathematically processed with the stored processed sample for the corresponding time slot to that of the input sample to produce a corresponding new processed sample.
Each of the new processed samples is stored in the memory in place of the stored processed sample for the corresponding time slot, thus the new processed sample replaces the previously stored processed sample.
Each new processed sample is also compared with a preset threshold value.
An output signal is generated when one of the new processed samples equals or exceeds the threshold value.
A stored processed sample is set to an initial state when the new processed sample for the corresponding time slot has reached the threshold value.
A stored processed sample is also set to an initial state after it is read out of memory when the new processed sample for the corresponding time slot has not reached the threshold value after a set number of said mathematical processing steps have been carried out for the corresponding time slot.