D2 (4fsc) FORMAT (IEC 60B (Sec) 200)
D2 (4fsc) FORMAT
A composite digital recording system with conventional analogue inputs and outputs. Internal A/D and D/A conversion uses 8-bit quantising at four times the sub-carrier frequency. Four digital audio channels are provided with 20-bit quantising at 48 kHz. Metal particle tape is used in cassettes conforming to the D1 outline. This approach extends the recording time for a given tape length (and hence size of cassette) by a factor of almost three compared to the D1 system.
| Signal system | ||
| Digital, composite. | ||
| Scanner | ||
| Geometry | Helical | |
| No. of rotating heads | 4 or 8 * | |
| Scanner diameter | 96.4 * | mm |
| Rotation speed | lOO * | rev/s |
| Tracks/revolution | 4 * | |
| Head-to-tape speed | 30.4 | m/s |
| Video track angle | 6.13 | degree |
| Track width | 35.0 | µm |
| Track pitch | 35.0 | µm |
| Azimuth | ±15 | degree |
| Tape Properties | ||
| Coercivity | 1500 | Oe |
| Type | Metal particle | |
| Width | 19.01 | mm |
| Thickness (total) | 13 (max) | µm |
| Tape Consumption | ||
| Linear | 131.7 | mm/s |
| Areal | 0.15 | m²/min |
| Shelf volume | 717 | cm³/h |
| Electrical Characteristics | ||
| Shortest wavelength | 0.79 | µm |
| Input data rate | 142 vid 3.85 aud | Mbit/s |
| Packing density | 2532 | bit/mm |
* Value for a typical implementation. The standard specifies the foot-print on tape,
not how it is to be achieved.
IEC 60B (Sec) 200
