Abstract: A PLL control circuit of an optical disc apparatus comprising: a voltage frequency conversion circuit that adjusts an oscillating frequency based on a control voltage to generate a first frequency signal; a phase comparison circuit that compares the phase of the first frequency signal with the phase of a second frequency signal generated based on an RF (Radio Frequency) signal at the time of photoelectric conversion of reflected light of the laser beam applied to an optical disc, to generate a phase difference signal indicating a phase difference between the first frequency signal and the second frequency signal; a charge pump circuit that generates the control voltage for synchronizing the phases of the first frequency signal and the second frequency signal according to the phase difference signal; a first detection circuit that detects whether the RF signal exceeds a predetermined level; a second detection circuit that detects whether the phases of the first frequency signal and the second frequency signal

Abstract: An optical disc signal processing apparatus comprising: a binarizing circuit configured to compare a level of an RF (Radio Frequency) signal obtained by photoelectrically converting a reflected light of a laser beam applied to an optical disc and a level of a DC signal, to output a binarized signal for reproducing information recorded on the optical disc, a level of the DC signal being adjusted to a level at which jitter included in the binarized signal is minimized.

Abstract: An optical disc signal processing apparatus comprising: a binarizing circuit configured to compare a level of an RF (Radio Frequency) signal obtained by photoelectrically converting a reflected light of a laser beam applied to an optical disc and a level of a DC signal, to output a binarized signal for reproducing information recorded on the optical disc, a level of the DC signal being adjusted to a level at which jitter included in the binarized signal is minimized.

Abstract: In an optical disc playback device, focus and tracking balance amounts are automatically adjusted to specified amounts. An error rate from an error correction circuit for performing error correction of data played back from an optical disk using the optical pickup is then measured, and if the measurement results are a specified threshold value or higher it is determined that the optical disc being played is an inferior disk. The focus and tracking balance amounts are then adjusted to as to reduce the error rate to a minimum level.

Abstract: A PLL control circuit of an optical disc apparatus comprising: a voltage frequency conversion circuit that adjusts an oscillating frequency based on a control voltage to generate a first frequency signal; a phase comparison circuit that compares the phase of the first frequency signal with the phase of a second frequency signal generated based on an RF (Radio Frequency) signal at the time of photoelectric conversion of reflected light of the laser beam applied to an optical disc, to generate a phase difference signal indicating a phase difference between the first frequency signal and the second frequency signal; a charge pump circuit that generates the control voltage for synchronizing the phases of the first frequency signal and the second frequency signal according to the phase difference signal; a first detection circuit that detects whether the RF signal exceeds a predetermined level; a second detection circuit that detects whether the phases of the first frequency signal and the second frequency signal

Abstract: An optical disc playback apparatus, which has an optical pickup receiving reflected light from an optical disc, comprises a signal level detector that detects a level of a signal obtained from the reflected light; and a determining circuit that, based on the level, determines which side the optical pickup is located on, an information recording area or an information non-recorded area of the optical disc.

Abstract: An optical disc playback apparatus which makes an optical disc rotate at given rotational speed and reproduces a record signal based on light reflected from the optical disc. The optical disc playback apparatus comprises a jitter amount detector that detects a jitter amount based on a signal obtained from the reflected light, and a rotational speed adjustment circuit that adjusts the rotational speed of the optical disc based on the jitter amount.

Abstract: In an optical disc playback device, focus and tracking balance amounts are automatically adjusted to specified amounts. An error rate from an error correction circuit for performing error correction of data played back from an optical disk using the optical pickup is then measured, and if the measurement results are a specified threshold value or higher it is determined that the optical disc being played is an inferior disk. The focus and tracking balance amounts are then adjusted to as to reduce the error rate to a minimum level.

Abstract: A paper coating composition is disclosed, which comprises:(A) a pigment, and(B) a copolymer emulsion prepared by polymerizing a monomer mixture containing:(i) 5 to 40 wt % of an .alpha.-olefin of the formula:CH.sub.2 .dbd.CH--R.sub.1wherein R.sub.1 is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms;(ii) 30 to 90 wt % of a vinyl ester of the formula: ##STR1## wherein R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom or an alkyl group having 1 to 18 carbon atoms;(iii) 1 to 30 wt % of at least one unsaturated carboxylic acid ester selected from the group consisting of an acrylic acid ester in which the alkyl moiety thereof has 1 to 18 carbon atoms and a methyacrylic acid or dibasic unsaturated carboxylic acid ester in which the alkyl moiety thereof has 1 to 18 carbon atoms; and(iv) 0.1 to 10 wt % of an unsaturated carboxylic acid. The paper coating composition of the invention provides improved printability and printing quality and is particularly useful for gravure printing.