System A
405-line is System A in the CCIR assignment of broadcast systems. The audio uses Amplitude Modulation rather than the Frequency Modulation in use on modern analogue systems. In addition, the system was broadcast in an aspect ratio of 5:4 until 3 April 1950 when it changed to the more common 4:3 format.
All System A transmitters used vestigial sideband transmission, with the single exception of Alexandra Palace in London, which closed down in 1957 when it was replaced by Crystal Palace.
| System | Lines | Frame rate | Channel bandwidth (in MHz) | Visual bandwidth (in MHz) | Sound offset | Vestigial sideband | Vision mod. | Sound mod | Aspect ratio | Effective resolution (4:3). |
|---|---|---|---|---|---|---|---|---|---|---|
| System A | 405 | 25 | 5 | 3 | -3.5 | 0.75 | Pos. | AM | 4:3 (5:4 before 1950) | 503 x 377 (theoretical) |
Read more about this topic: 405-line Television System
Famous quotes containing the word system:
“The truth is, the whole administration under Roosevelt was demoralized by the system of dealing directly with subordinates. It was obviated in the State Department and the War Department under [Secretary of State Elihu] Root and me [Taft was the Secretary of War], because we simply ignored the interference and went on as we chose.... The subordinates gained nothing by his assumption of authority, but it was not so in the other departments.”
—William Howard Taft (1857–1930)
“We now come to the grand law of the system in which we are placed, as it has been developed by the experience of our race, and that, in one word, is SACRIFICE!”
—Catherine E. Beecher (1800–1878)