PURPOSE: To perform the modulation of data with plural modulating systems by switching storage area designation information for the data on which modulation is being applied from a first storage means and a second modulating system selection signal with the modulating systems at a switching circuit.

CONSTITUTION: The latch circuits 3, 8 are reset with a reset signal f, and the data 00h is latched at a register 1 with a data write signal a, and an FF 2 is set with the signal a, and an output signal d goes to 1. The data D1 of 000 is outputted from a ROM 5 to the latch circuit 3, and also, the data D2 of 000 is outputted to ROMs 6, 7 via a line switching circuit 4. The latch circuits 3, 8 latch the data D1, D4 from the ROMs 5, 7 with a data read signal b, and the FF 2 is reset with the signal b, then, the output signal d goes to 0. Modulation data for the data modulatable in the data from the register 1, after being separated to the data D3 of one byte and remaining low-order data, is outputted from the ROMs 6, 7.