
Chapter
9
Signal sources
Signal sources play an important role in electronic
test and measurements, but their use is far from
limited to that. They form an essential part of
many common types of equipment. For example, a
stabilized power supply needs an accurate DC
voltage source as a reference against which to
compare its output voltage. Many pieces of elec-
tronic equipment incorporate an audio-frequency
signal source as an essential part of their oper-
ation, from the mellifluous warble of a modern
push-button telephone to the ear-shattering squeal
of a domestic smoke detector. And RF sources -
oscillators - form an essential part of every