| 摘要 |
<p>PURPOSE:To prevent a scale of the device from becoming large by inspecting a received orthogonal transform coefficient in a receiving side, deriving the highest degree of non-zero, and executing a sum-of-products operation only to the orthogonal transform coefficient within a range corresponding to its degree. CONSTITUTION:A variable length code word which has been received is decoded to its original quantizing signal by a variable length code decoding circuit 10, and a result of decoding is brought to reverse orthogonal transform by a reverse orthogonal transform circuit 11 and converted to a picture element signal. In a highest degree determining circuit 15 of the orthogonal transform efficient of non-zero, degrees (a), (b) of the orthogonal transform coefficients in the horizontal direction and the vertical direction outputted from the variable length code decoding circuit 10 are inspected, and in one block, the highest degree of the orthogonal transform coefficients of non-zero in the horizontal and the vertical directions is derived. Its outputs (c), (d) are read in the reverse orthogonal transform circuit 11, and the number of times of a sum-of-products operation is controlled. In such a way, the reverse orthogonal transform can be executed at a high speed without enlarging a scale of the device.</p> |
