| 摘要 |
A data expansion apparatus that performs data expansion operation for a data block unit in a constant period of time is provided. First and second memory devices are first initialized by storing zeroes at all of their addresses. Numeric data and number-of-zeroes data (i.e., data representing the number of successive zeroes) are input to the data expansion apparatus. A calculation circuit outputs a calculated value by combining the number-of-zeroes data, a previous calculated value and 1 together. A first selection circuit associated with the first memory device selects the calculated value and numeric data and output them to the first memory device for storing the numeric data at the address specified by the calculated value. This operation is then repeated. After the first memory device completes the expansion operation, it is switched to perform read operation and the second memory device begins to perform expansion operation through second selection circuit in a similar manner. In performing the read operation by the first memory device, the first selection circuit selects the output of a read address generator and zeroes from a zerodata device and outputs them to the first memory device for reading out the data at the address specified by the output of the read address generator. At the same time, zeroes from the zero data device are input to the first memory device to replace those data which have been read out. This operation is then repeated. After the first memory device completes the read operation, it is switched back to perform expansion operation and the second memory device begins to perform read operation through the second selection circuit in a similar manner. Therefore, the data expansion operation is performed by alternately switching the operations performed by the first and second memory devices.
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