Data Sheet

-136-
364. Distortion
Connect points A and B with the 4-wire (4) in project #362. Turn on the
switch (62) and you will hear very loud re siren. Turn off the switch (62)
and the re siren will go off. You may notice that the re siren is so loud
in this circuit that it sounds distorted.
This is happening because re siren waveform coming out of the 3-in-1
(11) is not just being amplied by the amplier (14) but the waveform is
being changed in some other way (i.e. the waveform is being distorted)
from its original form by the amplier (14). This can be due to several
different things such as: 1. The input signal may be too large for the
gain of the amplier (14) so that the maximum output voltage from the
amplier (14) is exceeded, 2. The amplier (14) may not be completely
linear over the full frequency range of the re siren signal, 3. Poor DC
biasing is occurring in the amplier (14) so that the amplication is not
occurring over the full re siren signal level.
365. Amplier Gain in dB
Connect points E and F with a 4-wire (4) in project #362. Turn on the
switch (62) and you will hear very loud space battle sounds. Turn off the
switch (62) and the sounds will go off. Based on the measurements from
project #363, the amplier gain in dB is about 10*log(190) = 22.8 dB.
366. Clipping
Connect points G and H with a 4-wire (4) in project #362. Turn on the
switch (62) and you will hear very loud music. Turn off the switch (62) and
the music will go off. You may also notice that the music in this project
is very distorted. A couple of the reasons for the distortion mentioned
in project #364 was due to the limitations in the maximum output
voltage from the amplier (14). When an amplier is over driven and the
amplied signal exceeds the maximum output voltage, then the signal will
be “clipped” or capped at the maximum output voltage supported by the
amplier. This is called clipping and is shown in the gure below.
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