Method and apparatus for monitoring a signal

摘要

A method of monitoring an analog signal output from a sensor comprising comparing the amplitude of the analog signal to a first high and low threshold, setting a primary monitoring signal to a first value when the amplitude of the analog signal exceeds the first high threshold, setting the primary monitoring signal to a second value when the amplitude of the analog signal decreases below the first low threshold, comparing the amplitude of the analog signal to a second high and low threshold, setting a secondary monitoring signal to a first value when the amplitude of the analog signal exceeds the second high threshold, setting the secondary monitoring signal to a second value when the amplitude of the analog signal decreases below the second low threshold, comparing the primary and secondary monitoring signals and determining from the comparison whether an error exists with the monitoring of the analog signal.

主权项

1. A method of monitoring an analogue signal output from a sensor comprising:
comparing an amplitude of the analogue signal to a first threshold pair, wherein the first threshold pair comprises a first high threshold and a first low threshold; setting a primary monitoring signal to a first value when the amplitude of the analogue signal exceeds the first high threshold; setting the primary monitoring signal to a second value when the amplitude of the analogue signal decreases below the first low threshold; comparing the amplitude of the analogue signal to a second threshold pair, wherein the second threshold pair comprises a second high threshold and a second low threshold and wherein the second high threshold is greater than the first high threshold and the second low threshold is less than the first low threshold; setting a secondary monitoring signal to a first value when the amplitude of the analogue signal exceeds the second high threshold; setting the secondary monitoring signal to a second value when the amplitude of the analogue signal decreases below the second low threshold; comparing the primary and secondary monitoring signals; and determining from the comparison of the primary and secondary monitoring signals whether an error exists with the monitoring of the analogue signal.