| 摘要 |
PURPOSE:To realize an operation circuit capable of dealing with the amplitude change of an input signal and using a small capacity ROM by compressing the dynamic range of the input signal. CONSTITUTION:Both the most significant bits of the signal to be inputted to an input terminal 1 and the part of the output signal of a delay circuit 2 from which a sign bit is removed are checked by an MSB detection circuit 16, and the dynamic range of data is reduced by one bit by issuing the cut-off instruction of the MSB to a bit cut-off circuit 17 and outputting the bit string of a order lower by one bit in the case when both the bits are '0', and by issuing the bit cut-off instruction of a least significant bit and outputting a high order bit string in the case that either of the two bits is used in '1'. After four stages of such dynamic range compression circuits are applied, the input signal of the operation circuit 4 comes to be four bits, and the operation circuit can be constituted of the ROM of very small capacity of 2<4>X2<4>X5=1280 bits. |
