Abstract: A method of preparing concealed information with a technique which does not substantially include mathematical control. Concealing processing information is produced by preparing information to be processed, diffusing the information to be processed with a spectrum pattern, and subjecting the spectrum spread information to be processed to phase modulation. The diffusion is performed by finding an EXOR of the information to be processed and the spread spectrum pattern.

Abstract: An optical recording medium for accurately deriving the address information or the disc rotation control information despite narrow track pitch and for recording signals to a high density, and a method and apparatus for recording and/or reproducing such optical recording medium. The optical recording medium has a wobbled groove and pits formed at a pre-set interval in an area between turns of the wobbled groove. The recording/reproducing method includes controlling rotation of the optical recording medium by a wobbled signal from the groove and detecting the position on the optical recording medium of a recording signal by pit signals detected from the pits. The recording/reproducing apparatus includes a detection device for detecting the wobbled signal from the groove and a detection device for detecting pit signals from the pits.

Abstract: An optical recording medium for accurately deriving the address information or the disc rotation control information despite narrow track pitch and for recording signals to a high density, and a method and apparatus for recording and/or reproducing such optical recording medium. The optical recording medium has a wobbled groove and pits formed at a pre-set interval in an area between turns of the wobbled groove. The recording/reproducing method includes controlling rotation of the optical recording medium by a wobbled signal from the groove and detecting the position on the optical recording medium of a recording signal by pit signals detected from the pits. The recording/reproducing apparatus includes a detection device for detecting the wobbled signal from the groove and a detection device for detecting pit signals from the pits.

Abstract: A process for preparation of a component of a catalyst for polymerization of .alpha.-olefins is disclosed. The process comprises the steps of heating a titanium containing component during and/or after milling operation thereof. The titanium-containing catalyst component thus produced makes it possible to produce polymers having a high stereoregularity in high specific yield.