No such thing as a dumb question.................that is how we learn!
Anyway, Signal Generators, at least in the context of test equipment, are
tunable RF sources that have modulation capabilities. If they are
synthesized, they can be accurate enough sources for calibrating the tuning
dials of receivers. They can also be used in conjunction with signal tracers
by injecting the signal through the different stages of a system and using
the signal tracer for tracing the path of that injected signal. A very
useful technique for locating a defective stage in a receiver. And yes,
signal generators are external pieces of test equipment.

Pete

wrote in message
...
Another dumb question from me.What are Signal Generators and how do they
work? Are they external devices.I don't know unless I ask? I own one or
two old Signal Tracers,I don't know anything about them or how they are
suppose to be used.
cuhulin