| 摘要 |
PURPOSE:To use more efficiently a memory by storing the 1st AD conversion result in the memory as it is and then storing the difference from last AD conversion result in a memory of less-bit constitution thereafter. CONSTITUTION:An AD converter 2, a collection memory 5, a transfer control circuit 9, etc., are provided. The converter 2 sends its output to a subtracter 3 and a memory 10 in synchronism with a clock 7. The output of a counter 8 is initially 0, so the output (a) of the circuit 9 is on. Consequently, switches of memories 11 and 12 are driven to store the output of the converter 2. The output of the circuit 9 turns off for the 2nd and succeeding outputs, so the input to a memory 12 turns off. Further, the memory 11 inputs the last AD conversion result stored in the memory 10 and the memory 10 inputs the current input result. Then, a subtracter 3 calculates the difference between outputs of the converter 2 and memory 11 and the difference is stored in a memory 15. Thus, the memories are used efficiently.
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