JPS6425350A - Periodical noise removing device - Google Patents

Abstract

PURPOSE:To remove switching noise without causing the increase in the noise removing time and a collecting scale by executing the timing of a first digital signal outputted from an analog digital converting means and a second digital signal to receive the noise removing processing with a noise removing means. CONSTITUTION:First and second analog signals S including a noise N of a constant period like a switching noise are respectively sampled by a timing with a difference 180 deg. phase respectively, converted to first and second digital signals Lch and Rch, the generating timing of noise is synchronized to the sampling timing of the first analog signal Lch, noise removing processing is executed to the second digital signal Rch, and while a timing 18 of the second digital signal Rch and the first digital signal Lch is executed, both Lch and Rch are converted 19 to an analog signal. Thus, only concerning the second analog signal, the circuit for removing noise may be provided and the circuit constitution can be facilitated.