Envelope detector useful in crash discrimination

摘要

A system (10) and method for detecting an envelope of received vehicle acceleration information (a(t)) useful in controlling actuation of a vehicle passenger safety device, wherein consecutive values for received vehicle acceleration information (a(t)) are stored and rank-ordered in a pair of rank-order filters (14, 16) to provide a highest-ranked value (aH) from among the most-recent half of the stored values, and a highest-ranked value (aH') from among the least-recent half of the stored values. The absolute value of the highest-ranked least-current value is taken and subtracted from the highest-ranked most-recent value to obtain a modified jerk measure (jH*). The absolute value of the thus-generated modified jerk value is taken to obtain a measure (m1) which tracks the envelope of the received acceleration information and, hence, is useful as an envelope detector when evaluating a crash waveform for purposes of controlling actuation of the safety device.