Schwartz, Jeffery, Schwaab, Mack, Blumenthal & Koch
Knocking detector
 A knocking detector senses engine vibration and produces an electrical signal corresponding to such vibration. This signal is then rectified and smoothed to produce a background noise signal. When the magnitude of the background noise level signal is greater than a reference value, the amplitude of the rectified signal is limited so that the background noise level signal has a substantially constant level. This limited background noise level signal is then compared with the initial signal from the sensor, and if the initial signal from the sensor is greater in magnitude than the background noise signal, the engine is considered to be in knocking condition. 
Nissan Motor Company, Limited
Y F G
Y02T F02P G01L
additional inventional inventional
Kenichi
Yoshida