INTEGRATING CIRCUIT

PURPOSE:To obtain a correct integral value by detecting a defect part of an input signal and integrating a signal corrected the input signal within the time. CONSTITUTION:A comparing circuit 5 is supplied with the input signal (a) and a reference signal (b) for detecting the defect part of the input signal (a), and outputs a comparison output signal (f) only when the signal (a) drops below the signal (b). Further, an integrating circuit 2 which has a proper time constant for compensating the defect part of the signal (a) sends out an integral output signal (e). A switch 3 sends out the signal (a) as a switch output signal (g) while the signal (f) supplied from the circuit 5 is at a low level or the signal (e) as an output signal (g) when the signal (f) is at a high level. An integrator 4 integrates the signal (g) for the input signal of an integration time specifying signal (d) to obtain an integral output signal (h). Further, a reset signal (c) is inputted from the integrator 4 to perform resetting.