PURPOSE: To reduce the power consumption and to resonably determine the level ratio of two sine waves, by using a ROM or gate circuit for setting analog signals outputted in a DTMF system and constituting the circuit by using one DA converter circuit.

CONSTITUTION: Counters 11 and 12 respectively divide CLK1 (frequency f1) and CLK2 (frequency f2) into 1/n1 and 1/n2 and data in ROMs 13 and 14 are respectively outputted by the outputs. An adder 15 adds the outputs of the ROMs 13 and 14 to each other and outputs the added output to a DA converter circuit 16. Hereupon, data are written in the ROM13 so that the converter circuit 16 can output a sine wave of a frequency f1/n1 in accordance with the output of the counter 11 when the output of the ROM13 is inputted in the converter circuit 16 through the adder 15 as it is by setting the output of the ROM14 at '0'. The same arrangement is made to the ROM14. Therefore, when the outputs of the ROMs 13 and 14 are added to each other and the added output is DA-converted by the circuit 16, a composite signals of two sine waves having frequencies f1/n1 and f2/n2, respectively, is outputted to an output terminal.