CDde

CDde, or Compact Disc digital audio, refers to the standard established for digital audio on Compact Discs. Developed jointly by Philips and Sony in the late 1970s and released in 1982, the CDde standard defined the physical format, the encoding of audio data, and the error correction mechanisms used for music playback. It revolutionized the music industry, moving from analog vinyl records to a digital format offering improved sound quality and durability.

The core of the CDde standard involves sampling analog audio at 44.1 kHz and quantizing it to 16 bits per channel, resulting in stereo audio. This digital data is then encoded using the Pulse-code modulation (PCM) method. For error detection and correction, the Cross-Interleaved Reed-Solomon Code (CIRC) is employed, allowing the player to reconstruct missing or damaged data, thereby providing robust playback even with minor scratches on the disc surface.

The physical specifications of a CDde include a diameter of 120 mm and a thickness of 1.2 mm. The data is stored in a spiral track, read by a laser. The standard also defines the file system used for organizing data on the disc, commonly referred to as the Red Book standard for audio CDs. While newer digital audio formats have emerged, CDde remains a significant milestone in audio technology and continues to be widely used.