PURPOSE:To suppress a frequency deviation and to improve the accuracy of a DTMF signal by forming a ratio setting means for counting up the outputs of a frequency dividing means, generating a specific integer frequency dividing ratio output and selecting an integer frequency dividing ratio of the frequency dividing means to obtain a decimal point frequency dividing output. CONSTITUTION:The titled device is provided with the frequency dividing means possible of selectively switching plural integer frequency dividing ratios and consisting of a COLUMN frequency dividing counter 12, a C-ROM1 16, a C-ROM2 18, a ROW frequency dividing counter 14, an R-ROM1 26, and an R-ROM2 28 and a ratio setting means for counting up the outputs of the frequency dividing means, generating a specific integer frequency dividing ratio output and selecting the integer frequency dividing ratio of said frequency to obtain a decimal point frequency dividing output and consisting of a COL UMN ratio counter 22, a C-ROM3 24, a ROW ratio counter 32, and an R-ROM3 34. Consequently, a highly accurate DTMF signal corresponding to reference frequency can be obtained.
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