摘要 |
A roughness sensor for measuring cycle-to-cycle decreases in engine speed comprises engine-event responsive flip flop means for controlling the alternate store-up and subsequent count-down of contents into a first storage means simultaneously with the alternate count-down and the store-up of contents into a second storage means. The storage means feed respective first and second comparators that produce respective first and second output pulses the widths of which are determined by the interval between the time a corresponding storage means is counted down to its starting value and the time of the next flip flop transition. A raw roughness output pulse in the form of just one but not both or neither comparator output pulses is passed by exclusive OR logic means to a speed normalization means that also receives the contents of the storage means opposite to that producing the raw roughness pulse. The speed normalization means produces a speed normalized roughness signal having a magnitude varying inversely with the magnitude of just those contents of the opposite storage means counted up during the width of the raw roughness pulse. |