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scrolling-h - display scrolling Hs

Display scrolling Hs on the screen as specified in CISPR 22 and similar EMC standards.

This is a simple JavaScript implementation of the code which will run on many of the web browsers independent to the operating systems.

This code is in the public domain.

For the colorbar test pattern specified in CISPR 32, see ITU-R BT.1729 Colour bar with Moving Element.

How to run it

Maybe you need to take some action to enable JavaScript on your browser.

If it is necessary, you can probably make the browser window full screen.

If you want to run it offline, you can save the file scrolling-h.html on your local storage.

Key operations

• b: black letters on white screen
• w: white letters on black screen
• 0-9: set font size (smaller to larger)
• f: make scroll faster
• n: default scroll speed
• s: make scroll slower
• p: pause scroll

Change Log

Version 0.1 (2013-02-09)

• First relase with no key operations at all

Version 0.2 (2013-02-16)

• Enable some key operations to change font size, colors, etc.

Version 0.3 (2015-11-15)

• To make it easier to count number of letters in a line, a bold face letter is printed for every ten letters and an underlined letter is printed for every fifty letters in the first line.
• New key assign: p key to pause scroll

Version 0.4 (2016-02-20)

• No longer use bold face letters. Ruler to help count characters are now displayed at the first line.

Another Implementation of Scrolling Hs

Bourne shell (sh)

while true; do echo -n H; usleep 1000; done

Related Software

• ITU-R BT.1729 Colour bar with Moving Element
• pingspray - heavily load the network for evaluation purpose

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