| 摘要 |
PURPOSE: An interpolation filter is provided to minimize a size of a lookup table and reduce a layout area of an IC by using the symmetry of filter coefficients and the symmetry of codes of lookup table data. CONSTITUTION: The first data storage portion(110) stores the first input data and outputs inphase lower data and inphase upper data. The second data storage portion(120) stores the second input data and outputs orthogonal lower data and orthogonal upper data. The first selection portion(210) outputs selectively the inphase lower data, the orthogonal lower data, the inphase upper data, and the orthogonal upper data. The second selection portion(220) outputs selectively the orthogonal upper data, the inphase upper data, the orthogonal lower data, and the inphase lower data. The first and the second address generation portions(310,320) output the data of the remaining bits except for the most significant bit. The first and the second storage portions(410,420) outputs an integrated value of a corresponding address according to an output of the first address generation portion. The third and the fourth storage portions(430,440) outputs an integrated value of a corresponding address according to an output of the second address generation portion. The third selection portion(510) outputs selectively the outputs of the first and the second storage portions according to the second selection signal. The fourth selection portion(520) outputs selectively the outputs of the third and the fourth storage portions according to the second selection signal. The first code inversion portion(610) inverts or outputs the output data of the third selection portion. The second code inversion portion(620) inverts or outputs the output data of the fourth selection portion. A filter result value generation portion(700) outputs the filter result values of inphase and orthogonal components. |
