What is the difference between a CD, a CD/R, and a CD/RW?

03/26/2015 19:30
During the recording process, the actual laser selectively heats tiny areas with the recording track into a temperature above the actual layer's melting point (500 - 700 C). In Contrast with regular CDs, the CD-R and also CD-RW discs provide an additional Cd-R/CD-RW region located in front of the particular lead-in area. Subsequently, your power will be reduced to a degree that's sufficient to become able to maintain the dye temperature with the required level.. Through continuous switching between composing along with studying power, a pit pattern corresponding compared for you to that of your conventional CD can be produced.

The write pulse initially includes a higher chance to produce the required heating with the dye. the physical characteristics in the amorphous stage are usually `frozen-in' throughout cooling, creating the recording just as permanent as just about any standard CD.


In your CD-RW disc, the actual recording layer is manufactured of an alloy of silver, indium, antimony and also tellurium. Each discs have an additional reflecting layer: golden for the CD-R, which accounts for that disc's distinctive appearance, as well as silver (aluminium) for your CD-RW.

The writing process: CD-RW Recording

The CD-R as well as CD-RW discs

Differences among CD-R/CD-RW discs as well as normal CD

The primary physical difference in between both of these disc sorts and additionally the normal prerecorded CD (audio or CD-ROM) is that your latter has absolutely no recording layer; the info is actually permanently stamped within the aluminium reflecting layer.

The creating process: CD-R

1.Program Memory Region (PMA), containing your track quantities of the recorded titles as well as their respective start preventing points.

There can be a positive change throughout terms of the actual data places about the disc. 2.Program Calibration area (PCA), which is used by the CDR 870 for you to calibrate the necessary laser power simply by means of a brief trial recording (Optimum Energy Calibration) whenever a disc can be loaded. the frequency read-out from the disc is continually monitored, as well as the speed is adjusted as needed to maintain the frequency with precisely 22.05 kHz. This calibration will be essential to permit production tolerances between individual discs, temperature variations etc. Regarding CD-RW writing, your laser energy used can be inside the range eight for you to 14 mW.

Digital details are written to the disc simply by burning (forming) pits inside the recording layer. An additional ? 1 kHz frequency modulation can be applied to provide the particular recorder by having an absolute period reference.

Both disc types use a track spiral which could be preformed during manufacture, upon which the audio information is written during the recording process. The Particular power in the laserlight - within the range 4 in order to 11 mW - brings about limited heating with the substrate as well as recording layer for you to approximately 250 C. the CD-R disc has a dye-based recording layer, having a reflectivity regarding 40 - 70 %, while the CD-RW disc features a phase-change recording layer having a reflectivity associated with 15 - 25 %. With this temperature your recording layer melts, decreasing its volume, while the substrate expands in to the room in which becomes available. While well since this first OPC, the mandatory laser energy is constantly optimized during recording through operating OPCs, which usually handle dust, scratches and other feasible variations over the disc surface.

Both CD-R as well as CD-RW discs have the exact same simple composition however with significant detail differences. Furthermore for the spiral pattern, the monitor includes a slight superimposed sinusoidal excursion associated with ? 0.3 mm with a frequency regarding 22.05 kHz.

The pulsed energy delivered from the laser beam melts the crystals in the heated areas right into a non-crystalline amorphous phase (`pits'), which includes a reduced reflectance than the remaining crystalline locations (`lands'). This particular monitor ensures that your recorder follows the identical spiral pattern as a regular CD, and contains the same width involving 0.6 mm as well as pitch associated with 1.6 mm as a standard CD. Inside its original state, this layer includes a polycrystalline structure. This additional area will be accustomed to store information certain towards the recording process, and can be also divided into two parts:

The frequency in the sinusoidal excursion is used through the recorder to manage the rate regarding rotation. This kind of distinction throughout reflectance permits the actual recorded data to become read-out, producing a new signal just like in which obtained from the normal CD


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