Compact Disc Player - CD Player Features

CD Player Features

CD players can employ a number of ways to improve performance, or reduce component count or price. Features such as oversampling, one bit dacs, dual dacs, interpolation, anti skip memory, digital and optical outputs are, or were, likely to be found. Other features improve functionality, such as random play and repeat, or direct track access. Yet others are related to the CD player's intended target, such as anti-skip for car and portable CD players, pitch control and queing for a DJ's CD player, remote and system integration for household players. Description of some features follows:

• Oversampling is a way to improve the performance of the low pass filter present at the output of most CD players. By using a higher sampling frequency, a multiple of the 44.1khz used by CD encoding, it can employ a filter with much lower requirements.
• One-bit DACs were less expensive than other types of DACs, while providing similar performance.
• Dual dacs were sometimes advertised as a feature because some of the early CD players used a single DAC, and switched it between channels. This required additional supporting circuits, possibly degrading sound quality.
• Interpolation, while not usually advertised, is present in most recent CD players. Interpolation is a way to correct errors that may be present on a compact disc, perhaps due to dust, scratches or dirt.