JPS6439831A - Analog/digital converter - Google Patents

Abstract

PURPOSE:To adjust an offset and a gain when a device is being operated, by estimating a digital data of an analog input signal which is omitted at the time of measuring the offset and the gain. CONSTITUTION:The offset quantity and the gain of a voltage/frequency transducer 3 are calculated each time by leading in a reference signal and a ground signal by a prescribed period, respectively, through a switching circuit 2 by a calculation control circuit 5 for executing a prescribed calculation, based on the counter output of a counter 4 for counting the number of output pulses from the transducer 3, and also, executing a control of the switching circuit 2. Subsequently, based on the offset quantity and the gain which have been calculated, a prescribed calculation is executed, the digital quantity corresponding to an unknown analog input signal is derived, and also, the digital quantity of an analog input signal which is not inputted for the calculation of the offset quantity and the gain is predicted. That is, an input signal data which has dissipated from a past data is estimated and supplemented (extrapolated). In such a way, even in the course of operation, the offset and the gain can be adjusted.