
367
it is difficult to avoid enough coupling via the amplifying devices to
cause appreciable interaction. Anyway, the use of anything like six
r.f. stages, even if technically feasible, would provide far too much
gain, so most of it would have to be thrown away. But is inter-circuit
coupling necessarily bad?
Introducing coupling between tuned circuits makes it more
difficult to predict their combined resonance curve. But by a rather
more mathematical investigation than is appropriate in a book of
this kind it can be shown that beneficial results are obtainable in this
way, as we shall now see.
20.6 Coupled Tuned Circuits
There are many way