| 摘要 |
PURPOSE:To improve the S/N of a noise signal in spite of the constitution of low power consumption by reading out a normal noise written in a reference memory in synchronism with the rotation of the motor of a mechanism part at the time of recording, arithmetically removing the normal noise in the memory from an output signal from a built-in microphone and reducing and removing the normal noise of the mechanism part from a recording signal which is recorded. CONSTITUTION:When recording is executed by the use of the built-in microphone 1 of a tape recorder, the level of the output signal from the microphone 1 is adjusted 3 and A/D converted 4, then the output from the converter is inputted in a subtracter. The synchronism of the rotation of the motor of the mechanism part is detected by a rotation detector 5, and a readout control means is constituted of a timing control circuit 6 and the detector 5. The normal noise previously written in the reference memory 7 is inputted in the subtracter 8 by the readout control means and the normal noise in the memory 7 is removed from the output signal from the microphone 1 by the subtracter 8, then the normal noise in synchronism with the rotation of the motor is removed from the recording signal which is recorded on a magnetic tape 11. |
