Chapter 4: Complex Vibration and Waveform Analysis Flashcards
components
frequency components
(partials in music)
an individual element of a complex system ( e.g., a sinusoidal component of a complex waveform or a component of an electric circuit)
the sinusoidal vibrations that make up a complex vibration.
Fourier Theorem
any complex vibration is the sum of various sinusoidal motions of varying amplitude, frequency, and phase.
a theorem stating that any complex oscillatory (vibratory) motion is the sum of various sinusoidal motions of varying amplitude, frequency, and phase.
fundamental period
(To) the duration of one cycle.
the amount of time it takes to complete one cycle of complex periodic vibration
fundamental frequency
the lowest frequency of a vibrating system; the reciprocal of the fundamental period of a complex periodic wave.
(fo or f1) fo = 1/To
complex vibration
the sum of two or more simple vibrations.
aperiodic vibration
a vibration without a repeating pattern in time.
periodic vibration
vibratory motion in which an object returns to the same point in space periodically (at equal periods of time) during the motion.
waveform synthesis
the process of combining several individual sinusoidal motions into a complex waveform.
adding sine waves to form complex waveforms.
harmonics
frequency components of a complex waveform that are whole-number multiples of its fundamental frequency.
(f2 is the first harmonic for this class)
missing fundamental
when the greatest common factor of a group of harmonically related frequency components of a waveform is not present in the waveform, this waveform has a missing fundamental.
periodicity
the concept that a periodic wave keeps repeating itself for an infinite amount of time.
noise
a stochastic (random) sequence of events resulting from the combination of a very large (infinite) number of unrelated components.
transient
a brief single event that ceases to exist after a very short time (door slam)
complex inharmonic vibration
the sum of a finite number of components that does not repeat its pattern within a time period of observation.
waveform analysis
(spectrum analysis)?
taking a complex waveform and breaking it down into individual components
time domain
representation of a phenomenon as a function of time
spectrum
a graphical representation of a complex waveform showing the waveform energy (amplitudes) of the individual components (y axis) arranged in order of frequency (x axis).
spectrum components
individual components, displayed as lines perpendicular to the x axis, are called spectrum components (spectrum components, frequency components) Thus, the spectrum provides a graphical representation of the Fourier series of a complex vibratory motion.
frequency domain
representation of a phenomenon as a function of frequency.
line spectrum (discrete spectrum)
a spectrum that consists of one or more separate vertical lines.
continuous spectrum
a spectrum in which the energy is spread across a rang of frequencies rather that at discrete sinusoidal components.
white noise
a noise that consists of an infinite number of sinusoidal components having the same amplitude, but random phase, that spread evenly across a wide frequency range; a noise that has a spectrum density that is independent of frequency.