A second generation CD provides improved sound quality over that provided by a first generation CD while remaining compatible with it has a higher sampling rate and has a data format of 1-bit AZ modulation. The higher sampling frequency is an integer multiple of the standard sampling frequency of 44.1 kHz used in the first generation CD to thereby simplify the clock signal generation circuitry. The recording system uses decimation filters to lower the sampling frequency of the 1-bit AS modulation signal so that the same signal can be used to manufacture both a first generation CD and a second generation CD. The playback apparatus is compatible and the kind of disk is determined based on the table of contents information, so that the appropriate clock signals can be provided to the decoders. In the case of the first generation CD being played back, the data is converted by an oversampling filter and a A2 modulator before being digital to analog converted.
7 Claims, 6 Drawing Sheets