QUADRUPLEX FORMAT Ampex (IEC 347)
The first commercially adopted VTR format, demonstrated by Ampex in 1956. Format details are included here for reference although 'quad' recorders can still be found in use today.
Very high head to tape speed was necessary to achieve the necessary high frequency response despite the limited short wavelength response of the conventional ferric oxide tapes available at the time.
| Signal system |
| Analogue, composite, segmented. |
| Scanner |
| Geometry |
Transverse |
| No. of rotating heads |
4 |
|
| Scanner diameter |
52.54 |
mm |
| Rotation speed |
250 |
rev/s |
| Tracks/revolution |
4 |
|
| Head-to-tape speed |
41.27 |
m/s |
| Video track angle |
90.33 |
degree |
| Track width |
253 |
µm |
| Track pitch |
397 |
µm |
| Azimuth |
Perpendicular
(to plane of scanner) |
degree |
| Tape Properties |
| Coercivity |
280 |
Oe |
| Type |
Ferric oxide* |
|
| Width |
50.8 |
mm |
| Thickness (total) |
38 |
µm |
| Tape Consumption |
| Linear |
397.0 |
mm/s |
| Areal |
1.21 |
m²/min |
| Shelf volume |
3620 |
cm³/h |
| Electrical Characteristics |
| |
Low band |
High band** |
|
| Sync tip carrier frequ. |
4.95 |
7.16 |
MHz |
| Blanking |
5.50 |
7.80 |
MHz |
| Peak white |
6.80 |
9.30 |
MHz |
| Shortest wavelength |
6.07 |
4.44 |
µm |
* Transverse particle orientation
** High band necessary for 625/50 colour --------- IEC 347
