Patent ID: 8391436

Claim:
A receiving apparatus comprising: a first receiving circuit that receives an input signal based on a clock signal, and outputs a first output signal, the first receiving circuit outputting a value of 1 as the first output signal when voltage of the input signal exceeds predetermined first receiving threshold voltage; a selecting circuit that exclusively selects and toggles between a receiving threshold voltage which is higher than the predetermined first receiving threshold voltage and a receiving threshold voltage which is lower than the predetermined first receiving threshold voltage, the selected threshold is used as a second receiving threshold voltage, alternately; a second receiving circuit that receives the input signal based on the clock signal, and outputs a second output signal, the second receiving circuit outputting a value of 1 as the second output signal when voltage of the input signal exceeds the second receiving threshold voltage selected by the selecting circuit; a comparison circuit that compares a value of the first output signal output by the first receiving circuit and a value of the second output signal output by the second receiving circuit; and an alarm generation circuit that generates an alarm signal when the comparison circuit determines that the values of the first and second signal outputs are different, wherein the alarm generation circuit is temporarily disabled when the selection circuit toggles the value of the selected second receiving threshold voltage.