| 摘要 |
PROBLEM TO BE SOLVED: To efficiently perform interpolation operations of encoded values A and B by simple circuitry. SOLUTION: A linear interpolation operating unit calculates an interpolated value C based on 4-bit values A (bits a<SB>3</SB>a<SB>2</SB>a<SB>1</SB>a<SB>0</SB>) and B (bits b<SB>3</SB>b<SB>2</SB>b<SB>1</SB>b<SB>0</SB>) expressing a negative number by two complement notation and a 4-bit interpolation rate D (bits d<SB>3</SB>d<SB>2</SB>d<SB>1</SB>d<SB>0</SB>) consisting of only a decimal part. A basic expression of C=(1-D)*A+D*B is transformed into an expression composed of an unsigned part that includes a sum of products with a bit d<SB>i</SB>or a logically inverted value e<SB>i</SB>of the bit d<SB>i</SB>(i=0, 1, 2, and 3), and indicates an absolute value of the interpolated value C, and a signed part indicating a sign of the interpolated value C. Then, 7 bits of bits c<SB>6</SB>through c<SB>0</SB>are generated from an arithmetic operation of the unsigned part, and logic judgement of the signed part is performed by considering a carry from the digit of the bit c<SB>6</SB>of the arithmetic operation of the unsigned part to generate a bit c<SB>7</SB>. Significant digits of the obtained 8-bit value C (bits c<SB>7</SB>through c<SB>0</SB>) are output as an interpolated value. COPYRIGHT: (C)2007,JPO&INPIT |
