| 摘要 |
To reliably distinguish between knocking signals derived from an internal combustion engine knock sensor from all the other signals likewise derived from the knock sensor, which includes background noise signals, statistically distributed disturbance signals and the like, a correlation signal is generated, and the received signal is correlated with the correlation signal, which is cyclically varying at an average frequency which is of the frequency of the expected knocking signal, or a whole number multiple thereof. An output recognition is provided upon correlation between the correlation signal and the signal from the knocking sensor. The system can be implemented by a signal generator (6, 61, 62; 63) which provides the correlation signal, correlation being effected by an AND-gate (7, 71, 72; 73), or by software in a microprocessor in which an incoming knocking signal is interrogated in cadence with cyclical variation at the frequency which is the expected knocking frequency of the engine.
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