| 摘要 |
PURPOSE:To calculate an elementary function such as trigonometric function at a high speed and with high accuracy by using a memory of small capacity to give an arithmetic operation to each of divided minor sections by means of an optimized polynomial of a low degree. CONSTITUTION:A quantizer 2 selects the higher rank bits of the input data and reads out a coefficient memory 4 via an address obtained by combining said higher rank bits with the lower rank bits of an address register 3. A selection circuit 5 selects these bits. A multiplier 6 multiplies the value selected by the circuit 5 by the value of an input register 1. This added value is added with the output of the memory 4 by an adder 6. The output of this addition is selected by the circuit 5 and multiplied by the value of the register 1. This arithmetic operation is repeated twice and finally the output of the adder 7 is extracted as the function value. Thus, the polynomial arithmetic is carried out in a divided minor section by means of an optimized coefficient. As a result, an elementary function is calculated at a high speed and with high accuracy.
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