Abstract: A method and apparatus for the computation of sliding windows and sliding window Fourier transforms and spectrograms requiring fewer operations in comparison with the current art. The sliding windows are realized using infinite impulse response filters. If the impulse response of one filter is equal to the impulse response of a second filter after a period of time, the impulse responses can be canceled thereby resulting in a composite filter with an impulse response of finite length. In certain realizations, the infinite impulse filters have identical components. These components can be combined into a single component in the composite filter thereby reducing the required number of computational operations. Sliding windows thus realized are employed in the generation of sliding window Fourier transforms and spectrograms. The windows can be modulated or unmodulated.

Abstract: Methods and systems that employ electronic data processing to identify a set of data which can be outputted to a mechanical, electromechanical, electronic, or other device to optimize the performance of that device. The data to be outputted is identified by writing a function which represents a current event or situation as a string of binary digits, finding that one of a series of functions similarly representing past or historical events which is most closely correlated with the current event-representing function, and outputting the string of digits representing the thus identified historical event. The functions representing historical events can be derived from the function representing the current event or from information supplied from a separate source.

Abstract: An optical neural net, content addressable memory that does not include electronics or slow optics in the feedback path. The memory comprises an optical vector-matrix multiplier that includes a spatial light modulator and input and output optics, and optical feedback means for returning the outputs of the multiplier to the inputs. Presentation of partial data at selected inputs causes the neural net to iterate at light speed to determine the corresponding output data. An arrangement is described for providing bipolar operations and for letting any group of elements act as the net stimulus.