
Chapter
8 Radio-frequency circuits
Radio-frequency equipment is used for a vast
range of purposes, including heat treating special
steels,
medical diathermy treatment for cancer,
heat sealing plastic bags, and experiments in
atomic physics. Nevertheless, as the name implies,
the original use was in connection with the trans-
mission of information by radio waves. The earli-
est form of this was wireless telegraphy (WT) using
Morse code. This was followed by wireless tele-
phony and, much later, broadcasting - radio and
television. So before we dive into RF circuits in
detail, a word might be in order about the different
forms of modulation employe ...