Voting of triple redundant circular data

A monitor circuit for assessing the validity among plural inputs each carrying circular data comprising:

• a comparison processor programmed to compare the plural inputs two-by-two to establish the validity of each input by grouping the plural inputs into pairs and for each pair generating a minimum angular difference by selecting the minimum of:
• (a) an absolute difference between the pairs of inputs, and
• (b) a conjugate of the absolute difference between the pairs of inputs;
• and
• wherein the processor is further programmed to test each generated minimum angular difference with a predetermine threshold to declare a pair to be in disagreement if the minimum angular difference for that pair exceeds the predetermined threshold;
• wherein the processor is further programmed to assess and declare invalid an input that is in disagreement with all other inputs paired against the input being assessed;
• and
• wherein the processor is programmed to filter the absolute value of the error between the pairs of inputs prior to comparing the filtered difference against a threshold and thereby apply an oscillatory failure detection filter in computing the absolute difference between pairs of inputs to ascertain how many of the plural inputs are valid;
• the oscillatory failure detection filter screening out momentary differences due to signal glitches and detecting oscillatory failures which would otherwise be undetectable at sufficiently high frequencies where a miscomparison lasts for a shorter duration than a monitor persistence time.