| 摘要 |
PURPOSE:To attain the improvement of an S/N characteristic and the saving of the capacity of a ROM at hard decision, by deciding the value of the output signal of an equalizer by switching a quantization deciding means and a minimum distance deciding means based on the position on a complex number coordinate deciding plane of the value of the output signal of the equalizer. CONSTITUTION:A selection means 1, when the value of the output signal of the equalizer is positioned within an area being an equal distance from the center of the complex number coordinate deciding plane, selects the quantization deciding means 2, and selects the minimum distance deciding means 3 when it is positioned at the area outside the above stated area. The quantization deciding means 2 segments the complex number coordinate deciding plane to sections in a grid shape, and also, outputs the decision data of the section in which the value of the output signal of the equalizer is included as a decided result. The minimum distance deciding means 3 sets one area being the equal distance from the center of the complex number coordinate deciding plane, and finds the decision data which minimizes a distance from the decision data in the neighborhood of the area, and outputs it as the decided result. Therefore, it is possible to correct a reception signal at an ideal position to be positioned originally on the complex number deciding plane, and to attain the improvement of the S/N at the hard decision.
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