| 摘要 |
A YUV-RGB digital conversion circuit which can be reduced in circuit scale. The YV-R conversion circuit in the YUV-RGB conversion circuit which converts digital luminance signal (Y) and digital color difference signals (U and V) into digital chrominance signals (R, G, and B) computes the R signal by approximately developing the coefficient 1.371 in the expression of R=Y+(V-128)x1.371 in terms of a finite number, 2-n (n: a natural number). The YV-R conversion circuit is provided with a plurality of bit shift circuits (42, 46, 50, 52 and 56) which output the products of input signals and 2-k (k: a natural number of <=n) by bit-shifting the input signals. A plurality of adders (44, 48, 54, 58, 60, and 62) which perform addition on terms of two sets of products of the input signals and 2-k (k: a multiplier), with the (k) having different values. Of the adders, the adder (44) is commonly used for the addition of a plurality of sets having k's with difference equal to one. The adders, in addition, are connected so that the adders can preferentially perform addition on the terms of 2-n with a small value and a corresponding pair of values. When the output of a preceding adder is to be bit-shifted by means of a bit shift circuit, the addition is performed by a plurality of number of times by omitting low-order bits having no paired augend in the addition by means of the adders of the next and farther stages.
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