
82 AMPLIFIERS
attempt to do so would result in a loss of signal (we are not, in this case,
concerned with maximum power transfer).
The input impedance of the amplifier should be high in comparison to
that of the input transducer (but not so high that excessive noise and hum
is produced). Conversely, the output impedance of the amplifier should
be low in comparison to the output transducer.
For this particular application we would not wish to extend the
amplifier's frequency response to cover the range normally associated with
high-quality audio applications (we will assume that a baby is not a
particularly musical creature!). Furthermore, th ...