Page 206 - Build Your Own Transistor Radios a Hobbyists Guide to High-Performance and Low-Powered Radio Circuits

FIGURE 13-6 Output collector current for small and large input sinusoidal
signals at the base-emitter junction of a transist.or. The X axis is time,
and the Yaxis is the output current.
When an output signal gets distorted, harmonics are generated, and as the input

signal level is increased, the fundamental frequency signal at the output is no
longer proportional to the input signal's amplitude. Thus the output level of the
fundamental frequency signal gets compressed (Figure 13-7). In the figure, the
straight Iline shows the input signal increasing linearly, whereas the output starts to
compress.