TV set (1 Viewer)

[mojako]

1. How fast does the electron gun of a "conventional television" (as referred to in the syllabus) scan the screen?
Jacaranda textbook says it's 1/50 second (but since it's odd and then even scans, there are 25 frames a second).
My teacher thought it's 24 fps, although he was talking about black and white TV set.
An article at howstuffworks.com says it's 30 fps (so it takes 1/60 second for a scan).

2. How many lines are there in a "conventional television"? Jacaranda says 625, and howstuffworks.com says 525 (and 480 for the black-and-white part of the article).

Just ut of curiosity... I'd be glad if someone can provides a bit of history of TV development. Thanks.

 

[velox]

2. How many lines are there in a "conventional television"? Jacaranda says 625, and howstuffworks.com says 525 (and 480 for the black-and-white part of the article).

For that, the resolution of a television ( a normal one not sd or HD) is 640x480. So it would be 480 horizontal lines.

 

[mojako]

Thanks.
What resolution is HD and SD? (SD = standard definition, isn't it?)

Having 640 x 480 resolution doesn't make it absolutely necessary to have 480 "lines" of scan, although it'd be much better if it's so.
One "line of resolution" can be represented by two "lines of scan", if you get what I mean... but this will cause some distortion of course...