Baird ratio

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Baird ratio

Postby Lowtone » Mon Mar 12, 2018 9:08 am

Hello,

The ratio of the Baird system was 3:7 with 30 lines. But the real ratio was 1:2; wich is a bit wider.
In order to make it happen, 3 lines on each side were wider than the lines composing the main section of the picture.
Wich leaves us with 24 lines of normal width and 6 larger lines.
If one normal line is 1 pixel wide, how wide are the 6 larger lines ?
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Re: Baird ratio

Postby smeezekitty » Mon Mar 12, 2018 11:33 am

Code: Select all
(24*1 + 6*x)/70 = 1/2

24 + 6*x = 70/2

48 + 12*x = 70

12x = 22

x = 22/12 = 1.8333


The 6 larger lines are 1.8333 or 11/6 times wider than the other lines.
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Re: Baird ratio

Postby Panrock » Mon Mar 12, 2018 12:09 pm

If the total width of the picture remains at 30 pixels and the 24 lines are 1 pixel wide, then the 6 lines cannot be wider.

But if they are wider, then the 24 lines must either be less than 1 pixel wide or the total picture width must be greater than 30 pixels.

In this case, the aspect ratio differs by 7/6, so the total picture width is: 7/6 x 30 pixels or 210/6 pixels. The width of the 6 fat lines taken together then is (210/6 - 24) pixels. Divide this by 6 and your answer is 1.833 pixels per fat line.

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Re: Baird ratio

Postby Lowtone » Sun Mar 25, 2018 8:38 am

Image
Thanks a lot for the math :!:

Code: Select all
Photographic reproduction of a picture broadcasted from London ( système Baird ), 30 scanning stripes ( 2100 elements ).
Notice the 3 larger stripes on the two lateral sides of the picture.
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