CONCEPT MAP

The chapter's own concept map is rooted at "Communication system" and branches out along the transmission chain: an input (information) signal is picked up by a transducer, boosted by an amplifier, combined with the carrier in a modulator, processed by the transmitter, and radiated by the antenna. From the antenna, the signal reaches its destination through the communication channel, which the map splits into wired and wireless paths -- wireless further branching into the three propagation modes covered in section 10.5 (ground wave propagation, roughly 2 kHz to 2 MHz; sky wave propagation, roughly 3 MHz to 30 MHz; and space wave propagation, roughly 30 MHz to 400 GHz) -- and wired branching to include fibre-optic communication. The map then extends the space-wave branch out to its major applications: satellite communication, RADAR and GPS. On the receiving side, the map mirrors the transmission chain in reverse: a receiving antenna feeds a demodulator, then a detector, then an amplifier, then an output transducer, which con …