A DSP of a DVD recorder includes: a gain setting portion determining appropriate values of a first gain α and a second gain β when playback of an optical disc is performed, recording the first gain α and the second gain β thus determined in a gain storing portion, and setting them in a main differential...http://www.google.com/patents/US7870463?utm_source=gb-gplus-sharePatent US7870463 - Optical disc recording and playback apparatus
