| 摘要 |
PURPOSE:To process data having high sampling frequency such as a digital vido signal and to realize a general-purpose filter with small scale of gates by providing a control circuit performing program control of addition/subtraction of an operating circuit and shift operation of a shifter. CONSTITUTION:Outputs of registers R1, R2,...R13 are selected sequentially by a selector 11, flter coefficients h1, h2,...h13 are amultiplied to the outputs respectively and the result is accumulated. In case of the multiplication of the 2's complement code, the multiplier and multiplicand are ANDed at each bit of the multiplier when the multipicand is, e.g., (00110101) and the multiplier is, e.g., (10001011), that is, each 8 bits, they are added while shifting the bits, and the most significant bit is subjected to subtraction, and since the time required for operation is longer when the multiplication is conducted for the number of order of the filter, the filter coefficient h1-h13 are converted into binary absolute value and the code, and an ALU12 performs subtraction when the sign is (-) at each bit 1 location from the least significant bit of the binary absolute value and the ALU12 performs addition when the sign is (+). |
