VIDEO 8 FORMAT (IEC 843)
An embedded track finding and following system avoids the need to read a longitudinal control track at slow tape speed. Very small cassettes are used and the current (type P5-) metal particle tapes offer recording times up to 2h. Thinner metal evaporated tapes are expected to become available which will offer extended times. The format includes 'buried' FM audio recording on a 1.5 MHz carrier and a variety of PCM audio options using 10- to 8-bit companding.
| Signal system |
| Analogue, composite video, FM audio, PCM audio. |
| Scanner |
| Geometry |
Helical |
| No. of rotating heads |
2 |
| Scanner diameter |
40 |
mm |
| Rotation speed |
25 |
rev/s |
| Tracks/revolution |
2 |
|
| Head-to-tape speed |
3.12 |
m/s |
| Video track angle |
4.91 |
degree |
| Track width |
34.4 |
µm |
| Track pitch |
34.4 |
µm |
| Azimuth |
±10.0 |
degree |
| Tape Properties |
| Coercivity * |
1500MP or 950 ME |
Oe |
| Type |
Metal particle or m. evaporated |
| Width |
8.00 |
mm |
| Thickness (total) |
13.0 MP or 10.0? ME |
µm |
| Tape Consumption |
| Linear |
20.05 |
mm/s |
| Areal |
0.01 |
m²/min |
| Shelf volume |
59.4 |
cm³/h |
| Electrical Characteristics |
| Sync tip carrier frequ. |
4.2 |
MHz |
| Peak white |
5.4 |
MHz |
| Chroma s/c |
0.732 ** |
MHz |
| Shortest wavelength |
0.58 |
µm |
* Tape magnetic properties are not stated in the standard; suitability is ascertained
by comparison with reference tapes.
** Strictly 46.875fh. Track 1 has phase continuous chroma s/c, track 2 has phase retarded
90° at every horizontal interval.
IEC 843
