US Patent 7676323 Signal processing method for an engine knock signal

The duration of a knock detection window over which a filtered knock signal is single-point DFT-processed for engine knock detection is user adjustable. The knock detection window is defined by at least two overlapping identical duration sub-windows, and the extent of the sub-window overlap is changed to adjust the duration of the knock detection window. The DFT processing is performed over each sub-window and the processing results are combined for knock detection.