Page 431 - PPL-engelsk 2025
P. 431
Communication
Back to table of contents
4.13.2 Waveforms and modulation
The shapes and properties of waves are called waveforms.
Modulation is the process of changing a signal to transmit information.
In communication systems, modulation is used to combine a low-frequency
signal (such as sound) with a high-frequency carrier signal so that it can be
transmitted efficiently over long distances.
4.13.2.1 N0N
The NON signal is just a carrier wave. It can be heard
as a hiss if you listen to the frequency.
4.13.2.2 A1A
It wasn't long before people figured out how to code using radio signals.
Initially, this was done by interrupting the transmission with intervals of size,
like a dot or a dash in the Morse code system.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 431
