Solid State Shortwave Receivers For Beginners - The Listeners Guide

input of the circuit so that it is amplified for a second time. This is
sometimes given its alternative term, ‘reaction’.
One effect of regeneration is to increase the gain of the circuit,
but the important feature is that it will not increase it by an equal
amount on all signals, or even on all parts of each signal.
For instance, the positive input half cycles are at a greater
amplitude at the output than are the negative ones, and therefore a
larger amount of feedback is produced on the positive input half cycles.
This causes a larger increase in gain on the positive input half cycles than
on the negative ones, and regeneration thus increases the detection
efficiency of the circuit. This is illustrated in Fig.9 which shows the
input, output, and output after regeneration waveforms of typical
regenerative detector, with an unmodulated R.F. input.
A regenerative detector has a considerable level of gain, and it
is far more sensitive than a simple diode detector of the type used in
the crystal set.
Increased Selectivity
Using regeneration also greatly boosts the selectivity of a receiver.
If a graph showing frequency versus sensitivity for a crystal set was plot-
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