| 摘要 |
PURPOSE:To decrease the storage capacity of a storage device and its access speed by storing a PCM signal in a storing circuit after executing a digital compression once, executing its time compression, and converting it to an analog signal after executing a digital expansion, when executing readout. CONSTITUTION:In a writing circuit 3, first of all, an input signal of 8 bits is latched to a latching circuit 7, converted to a signal of 4 bits by a digital compressing circuit 8, and latched to a latching circuit 10 through a signal switching circuit 9. In the same way, the next input signal of 8 bits is converted to a signal of 4 bits, latched to a latching circuit 11, and two signals of 4 bits which have been latched in the latching circuits 10 and 11 are stored as signals of 8 bits in a storing circuit 5. In a readin-out circuit 4, upper 4 bits and lower 4 bits in the signals of 8 bits which have been read out of the storing circuit 5 are converted successively to a PCM signal of 8 bits. In this way,the capacity of the storing circuit can be decreased to 1/2. |
