| 摘要 |
PURPOSE:To read out a record having high density and large capacity, by simultaneously irradiating optical beam to three adjacent information tracks, and subtracting the signals which have multiplied signals of both adjacent information optical beams, by the quantity of crosstalk, from a signal of the middle information optical beam. CONSTITUTION:Optical beamsI,I',I'' are used as a read out optical beam, and quantities of light for signal obtained by irradiating tracks -1, 0 and +1 are denoted as S', S and S'', respectively. These S' and S'' are multiplied by the quantity of crosstalk (k), and when its result is subtracted from S, an expression of S-kS'- kS'' (1-2k<2>)S0 is obtained. In this case, since K<2> is small enough, S0, that is to say, a signal S0 in case when optical beam has irradiated the center part of the middle track is obtained, and the quantity of crosstalk in this case becomes a decreased form. In this way, when said operation is executed the quantity of crosstalk is made small apparently, and a record having high density and large capacity is read out. |
