| 摘要 |
PURPOSE:To insert a signal into a digital signal, to restore the signal to an analog sound signal and to minimize the capacity of recording medium by storing the digital signal and the compressed digital signal, giving a prescribed stretching to the compressed signal to restore the data. CONSTITUTION:A sound signal from an analog sound input terminal 1 is quantized at the sampling frequency f0 of a sampling frequency generating device 1 with a first A/D converter 3. With an A/D converter 4, the difference in the sound signal is quantized at a second frequency in which the frequency from the generating device 1 is the same frequency and the phase is different. To the difference value of a digital signal converted by the A/D converter 4, a prescribed compression is given by a compressing part 5, and stored into a buffer memory 7 together with a digital signal from the A/D converter 3. A stretching part 8 gives the stretching to return to an original level toward a second data signal from the memory 7, and a logical part 9 converts a difference value to an absolute value. The signals are temporarily stored into a buffer memory 10 and the output of the logical part 9 is inserted into the signal of the A/D converter 3.
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