PURPOSE: To D/A convert many bits by simple circuit configuration without using an expensive D/A convertor by analog-coverting differential processed and range compressed digital signals using a multiplication type D/A convertor of small number of bits and an analog integrating circuit.

CONSTITUTION: Digital signals of specified bit from an input terminal 1 are differential processed by a differential processing circuit 2, and the output is inputted to a range processing circuit 3. Data differential processed by the circuit 3 are expressed in mantissa part 9 bit and exponential part 4 bit by floating decimal point expression, and inputted to an absolute value calculating circuit 4 and a D/A convertor 5. Absolute value of the data including positive and negative is calculated by the circuit 4, and inputted to a multiplication type D/A convertor 6. Mutiplication signals from the convertor 5 in which exponential part is analog-converted are inputted to the convertor 6, and analog-converted signals are outputted from the convertor 6. Output of the convertor 6 is processed by an analog integration circuit 7 and a de-emphasis circuit 8, and data of multiple bit are D/A converted by simple constitution.