FINALS- UNIT 2 Flashcards
Complex Waves
Combo of two or more pure tones of different frequencies
Reinforcement Interference
Also known as constructive interference
When two waves are exactly 0° out of phase
wave is twice the amplitude
Cancellation Interference
Also known as Destructive Interference
When two waves are exactly 180° out of phase
combined amplitude is zero
Fundamental Frequency f0
Lowest frequency component of a complex periodic wave
Harmonic
Integer multiple of the fundamental frequency
The _________ harmonic is the equivalent to the fundamental frequency
First Harmonic
Waveform
Amplitude as a funciton of time
temporal waveform
Spectrum
Graph of amplitude function of frequency
amplitude spectrum
Fourier’s Theroem
Complex waves can be broken down into pure tones
Square Wave
- Sum of odd harmonics (1, 3, 5, 7)
- amplitude decreases with increasing frequency
- sounds like clarinet
Transients
brief abrupt sound
sounds like click or pop
White random noise
many frequency components with same amp
Filters: Four basic shapes of continuous spectrum
- Flat Spectrum
- High Pass filter
- Low Pass filter
- Band Pass filter
Flat Spectrum
energy at all frequencies
High Pass Filter
Filter that has energy at frequencies higher than some cut off frequency
Low Pass Filter
Filter that has energy at frequencies lower than some cut off frequency
Band Pass Filter
Filter that has energy at frequencies between two cut-off frequencies
Standing Waves
Propagating & reflected waves interact to form a pattern on the string
*when reflected waves flip
- longest pattern that can occur, “first wave of vibration”
- Lowest possible vibration frequency for string (Fundamental Frequency)
Node
Zero displacement on wave
Antinode
Maximum displacement on wave
As mode of vibration ___________, amplitude _______
Increase, decrease
Tubes open at both ends
antinodes on end, nodes in center
called half wave-length resonators
λ = 2L
Tubes open at one end
- Node at closed end, antinode at open
- First mode of vibration corresponds to 1/4
- λ = 4L
- Only at odd harmonics
Tubes open at ____ end(s) are the model for the ear canal
one
Immittance
General term that describes how well energy flows through system
- impedance
- admittance
Impedance
dictates how much force must be applied to the mass to move it back and forth
Z = f/v
Mass Reactance
component of impedance due to mass
Xm
increases with frequency
Stiffness
Xs opposes movement due to restoring force
- opposes low frequency oscillations more than high
- Xs decreases with increasing frequency
- Stiff objects move more quickly
Resistance
- Frequency independent
- Determines how long system will oscillate