PURPOSE: To suppress the noises generated in the intervals of music, by converting a digital signal showing a music number into a sine wave signal to have a zero cross at the joint and then recording said sine wave signal.

CONSTITUTION: The reference pulse signal given from a signal generating circuit 1 is converted into a sine wave signal by a circuit 5. Then a 4-bit signal showing the sound recording start time point is generated through an operation of a circuit 3 and synchronously the reference pulse signal. These a signals are converted into 1-bit serial digital signals by a parallel-serial converting circuit 4 with a dividing pulse signal which is obtained giving 1/4 division to the pulse signal through a frequency dividing circuit 2. The serial digital signal is inverted and applied to a TR6. The TR6 is turned off only when said digital signal has a level "0" and kept on in other periods. Therefore the sine wave signal transmits through the TR6 only when the TR6 is off. As a result, a symbol signal converted into a sine wave and equivalent to said serial digital signal is applied to an amplifying circuit 7.