Patent ID: 8081559
Filing Date: 2011-12-20
Classification: G11B

Abstract:
1. A recording and reproducing, the apparatus comprising: a modulated irradiator for irradiating the servo pits with a light beam, the intensity of the light beam being modulated by a modulating wave with the wavelength of the light beam unchanged; a photoelectric converter for converting reflected light from the servo pits into electric signals; a synchronous demodulator for subjecting the electrical signal to synchronous demodulation using the modulating wave; wherein the recording and reproducing apparatus performs tracking servo control while reading servo pits that are formed so as to produce optical contrast by a concavo-convex structure on a surface of a recording medium; and a frequency of the modulating wave is higher than a frequency (V/L) calculated from a distance L between the servo pits and a traveling speed V of the recording medium.