O'Reilly logo

Broadband Telecommunications Technologies and Management by Riaz Esmailzadeh

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

7Digital Modulation

Historical Note

Discrete data telecommunications require technologies similar to analogue signals as data need to be transmitted over a physical medium using electrical currents or electromagnetic waves. Modulation of discrete data onto a carrier signal dates back to electrical telegraphy and on–off keying: a telegraph key (pictured)1 connects and disconnects the flow of electricity and through this process information is communicated [1]. The word ‘key’ defines to this day the digital modulation techniques used to transmit discrete signals.

image

Modulation of discrete data onto an electromagnetic wave carrier was shown by Guglielmo Marconi (pictured)2 in 1895. His experiments led to the development of the wireless telegraph, and he is famously credited as the inventor of wireless telecommunications. The technique ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required