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:
“Few white citizens are acquainted with blacks other than those projected by the media and the so—called educational system, which is nothing more than a system of rewards and punishments based upon one’s ability to pledge loyalty oaths to Anglo culture. The media and the “educational system” are the prime sources of racism in the United States.”
—Ishmael Reed (b. 1938)
“For the universe has three children, born at one time, which reappear, under different names, in every system of thought, whether they be called cause, operation, and effect; or, more poetically, Jove, Pluto, Neptune; or, theologically, the Father, the Spirit, and the Son; but which we will call here, the Knower, the Doer, and the Sayer. These stand respectively for the love of truth, for the love of good, and for the love of beauty.”
—Ralph Waldo Emerson (1803–1882)