Table of Contents
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| Disc | Description | |
|---|---|---|
| Playing time | 74 minutes, 33 seconds maximum | |
| Rotation | Counter-clockwise when viewed from readout surface | |
| Rotational speed | 1.2-1.4 m/sec. | |
| Track pitch | 1.6 µm | |
| Diameter | 120 mm | |
| Thickness | 1.2 mm | |
| Center hole diameter | 15 mm | |
| Recording area | 46 - 117 mm | |
| Signal area | 50 - 116 mm | |
| Material | Any transparent material with 1.55 refraction index. Usually polycarbonate | |
| Minimum pit length | 0.833 µm (1.2 m/sec.) to 0.972 µm (1.4 m/sec.) | |
| Maximum pit length | 3.05 µm (1.2 m/sec.) to 3.56 µm (1.4 m/sec.) | |
| Pit depth | Approximately 0.11 µm | |
| Pit width | Approximately 0.5 µm | |
| Number of channels | 2 channels (four channel recording possible) | |
| Quantization | 16-bit linear quantization | |
| Quantizing timing | Concurrent for all channels | |
| Sampling frequencySample rate | 44.1 kHzChannel bit rate | 4.3218 Mbps |
| Data bit rate | 2.0338 Mbps | |
| Data-to-channel bit ratio | 8:17 | |
| Error correction code | Cross Interleave Reed-Solomon Code (CIRC) (with 25% redundancy) | |
| Modulation system | EFM |
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| Specification | Description |
|---|---|
| Channels | 2 channel (stereo) |
| Bit - depth | 16-bit |
| Data encoding | Linear PCM |
| Sample rate | 44.1 kHz |
The sample rate of 44.1 kHz was inherited from the widespread practice of using a PCM adaptor to convert digital audio into an analogue video signal for storage on a U-matic videocassette. This was the most economical way of transferring audio from the recording studio to CD manufacturers.
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| Info | ||
|---|---|---|
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Adapted from Ken C. Pohlmann, The Compact Disc: A Handbook of Theory and Use. Madison, Wisconsin: A-R Editions (1989): 72-80. |
CD players play 75 of these 588 bit data frames per second, thus transmitting 44,1000 samples per second.
Data storage and transmission
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