Electronic skip protection is a memory buffer system used mainly in some portable Compact Disc (CD) players and all MiniDisc (MD) units.

Technology

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When the buffering circuitry is in operation, the compact disc is read at a fixed read speed or CAV and the content is compressed and fed to RAM within the player. The RAM is then decompressed and sent to the amplifier. When the disc reading is interrupted, the player momentarily reads the data stored in RAM while the tracking circuitry finds the passage prior to the interruption on the CD.

Another method has the disc rotating at variable or CLV speed (the normal rotation method for a CD player), but at a slightly higher speed than with the buffer feature switched off. The buffer method is the same as before.

History

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The technology surfaced around 1992-1993 as a physically smaller alternative to the bulky rubber shock absorbers utilized in portable players at the time. It much reduced the size of the hitherto bulky players designed for use in moving cars, in particular. Small rubber shock absorbers are still used, but are less effective than the bigger pre-1993 ones.

When first introduced, 3 seconds was the maximum buffering time. As of 2006 times range from 10 seconds to "skip-free," where the player will rarely skip.

Due to the nature of the ATRAC compression scheme, all MD decks and portables buffered at least 10 seconds when the format was introduced in 1992. As of 2006, MD units have much bigger buffers.

Pros

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• Interruption-free performance.

Cons

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• Audio quality may be slightly worsened due to compression artifacts when the system is in use. Quality is improving as compression algorithms improve.

• Battery life is shortened due to the fixed (CAV) read speed of the disc and power required by the memory.
  • Older players (1992-1997) had at most half the battery life when the skip protection system was in use.
  • Players from 1997 have more power-efficient skip protection.

Trade Names

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"ESP", "Anti-Skip", "Anti-Shock", "Joggable" "G-Shock Protection" (Used by Sony), etc.