Abstract: A discrete cosine transform circuit including a shuffle circuit with n (n is an integer) shuffle stages, the n shuffle stages sequentially having 2.sup.n, 2.sup.n-1, . . . , 2.sup.1 input/output stages in such a manner that a first one of the n shuffle stages has the 2.sup.n input/output stages and a nth one of the n shuffle stages has the 2.sup.1 input/output stages, the nth shuffle stage including first and second RACs for performing a discrete cosine transform using a distributed arithmetic process, the first RAC having 2.sup.n-2 input/output stages, the second RAC having 2.sup.n-1 input/output stages. A path switching section is connected to the input stages of the shuffle circuit for changing a transfer path of output information from the output stages of the shuffle circuit according to whether the discrete cosine transform to be processed is a forward discrete cosine transform or an inverse discrete cosine transform.

Abstract: A magneto-optical disk comprising a polycarbonate substrate, a first protective coating coated on the polycarbonate substrate, a recording layer coated on the first protective coating, a second protective coating coated on the recording layer, a reflective layer coated on the second protective coating, wherein the first and second protective coatings comprises at least one multiple layer of SiNx/TiO.sub.2 /SiNx layer or a coating of an amorphous AsxS.sub.1 -x layer. The present invention can provide a magneto-optical disk of a good anti-reflection effect as a result of considerable increase of the .theta.k value, and a good stability against the oxidation.