OFFSET SIGNAL DETECTION CIRCUIT AND SIGNAL DETECTION APPARATUS EMPLOYING OFFSET SIGNAL DETECTION CIRCUIT

PROBLEM TO BE SOLVED: To provide a signal detection apparatus which more accurately detects an offset value varied by temperature drift and more accurately corrects a detection signal by using the offset value.SOLUTION: A signal detection apparatus comprising signal detection means 92u which detects a signal flowing on a signal line further comprises: reverse-phase signal detection means 91 which is disposed in such a manner that an ambient temperature becomes approximately equal to that of the signal detection means 92u, and detects a reverse-phase signal of the signal flowing on the signal line; offset signal calculation means 931 and 932 which calculate an offset signal by adding the signal detected by the signal detection means 92u and the reverse-phase signal detected by the reverse-phase signal detection means 91 and dividing a result of the addition with two; and correction signal calculation means 933u which calculates a correction signal by subtracting the offset signal detected by the offset signal calculation means 931 and 932 from the signal detected by the signal detection means 92u.