Attenuation versus frequency characteristic. The attenuation versus frequency characteristic of a
circuit is the amount of loss through the circuit as a function of frequency. The function is usually
shown with the amplitude in decibles relative to a certain reference level on the vertical scale, and the
frequency on the horizontal scale. Figure 5-4 illustrates the attenuation versus frequency characteristics
curve for an audio low pass filter. This low pass filter was designed for use on an intelligibility
a. Various devices are used for precise adjustments of the characteristics of attenuation versus
b. For instance, in high-fidelity recording equipment the equalizer is often used instead of the
bass and treble controls to help obtain the desired audio response.
Figure 5-4. Attenuation. Attenuation versus frequency characteristics of a lowpass filter that might be
used for communication purposes
Learning Event 2:
DESCRIBE AND IDENTIFY THE COMPONENTS AND FUNCTIONS OF A TYPICAL AUDIO
Speakers. Speakers transform energy from one form to another; i.e., electrical to mechanical
energy. The speaker will convert the audio signal sent to it from the amplifier and change it into a
instantaneous pumping motion. This motion (fig 5-5) is strong enough to transport air in vibrating
patterns of waves that the ear hears as sound.