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Definitions |
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Speech
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The production of language
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frequency domains display ________.
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spectrums
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attentuation means?
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softer or less
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IPA
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International Phonetic alphabet was created in 1988
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Impedance
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Acoustic, mechanical, or electrical resistence to motion or sound transmission
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what is periodicity?
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?? (look up)
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what determines frequency resolution?
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sampling rate
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Amplitude
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The measure of magnitude (intensity, strength) of sound signal. It is the extent of molecular displacement, the greater the degree of molecular displacement, the highter the amplitude or intensity of sound.
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Phonemic
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abstract system of sounds, i.e. /s/
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for digital representation of speech, numbers that represent frequencies we don't want are _________.
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disregarded
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what carries 95% of the intelligibility in speech?
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consonants
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impedance =
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force (either mass or stiffness)
____________
velocity
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________ is the electrical equivalent of mass and opposes high frequency energy.
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inductance
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explain the representation of speech in a digital recorder
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DIAGRAM!
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A _________ changes a "real world" event (e.g. acoustic signal) into an electrical event (e.g. voltage change) that you can store and/or utilize.
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transducer
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what determines damping?
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resistance (that is, frequency-independent attenuation)
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Decibel
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A measure of sound intensity. It equals one tenth of a bel.
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Octave
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Indication of the interval between two frequencies. The ratio is always 1:2 thus, each octave doubles a particular frequency
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Acoustics
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The study of the physical properties of sound and how sound is generated and propagated
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Coarticulation
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Influence of one phoneme upon another in production or perception. Two different articulators move at the same time to produce two different speech sounds
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Pitch
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is a sensory experience related to changes in frequency a physical event. A sound of higher frequency is perceived to have a higher pitch. The normal young adult can resond to 20-20,000 hz
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Harmonics
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In a periodic complex sound, all frequencies can be characterized as a whole number multiples of the fundamental frequency. Thses tones/harmonics, occur over the fundamental frequency.
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Displacement
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A change in position, air molecules are said to be displaced because of the vibratoroy action of an object
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devices or separating portions of a complex wave form is _____.
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filters
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a system is called "________ ______" for frequencies below Fc.
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stiffness dominant
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the __________ the cavity, the higher the resonance.
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smaller
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how many steps are there in 16-bits?
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65,536
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what dB range does speech have?
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40 dB
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true or false: a transducer changes acoustic energy into something we can see.
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true
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what does bits of quantization determine?
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amplitude resolution
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true or false: digital is continuous
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false (non-continuous)
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in a free field, sound travels _______
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unobstructed
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Elasticity
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A property that makes it possible for matter (that helps transmit sound) to recover its form and volume when subjected to distortion
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Sound wave
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Movements of particles in a medium containing expansion and contractions of molecules
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Rarefaction
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The thinning of air molecules when the vibrating object returns to equilibrium
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Language
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A code system of symbols used to express concepts formed through exposure and experience
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Frequency
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The measure of the number of cycles per second or Hz. It is one instance of compression and rarefaction. A period is the amound of time needed for a cucle to be completed. The medium that transmits the sound does not affect the frequency of sound but it does affect the speed of sound
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what are the two different domains?
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time and frequency
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what has 95% of the power in speech?
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vowels
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true or false: low pass filters reject low frequencies and let high frequencies pass.
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false
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what is aliasing?
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higher frequency signals being wrapped around to the low frequency side of the spectrum
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in a low pass filter, vowels or consonants are rejected
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consonants
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what are the digitization parameters?
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-sampling rate
-bits of quantization
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true or false: 3/4, 5/4, ..... waves also fit nicely in a 1/4 wave resonator.
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true
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mass and stiffness reult in a "______ ______".
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natural frequency
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what type of distortion causes peak clipping?
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frequency distortion
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What occurs in time/phase distotion?
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time/phase relationships between frequencies are no longer maintained
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Aperiodic waves
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Those that do not repeat themselves at regular intervals
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Sound (physically)
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It is the result of vibration or disturbance of air. (Perceptually) The audible vibration or disturbance in the air.
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how do we prevent aliasing?
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sample at the Niquist frequency
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_______ waves are only pure if they've been turned on gradually and left on for awhile.
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sine (puretones)
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whether diffraction occurs depends upon the relationship between...
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size of object and wavelength
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what is reverberation?
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an echo, time off arrival differences between the incident waves and reflective waves
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consonants are periodic or aperiodic in nature?
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aperiodic (noise is too)
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sawtooth waves contain what type of harmonics?
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odds and evens
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at the point where the waves cross in a tube _____ exist, there is zero velocity
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nodes
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who has more resonance characteristics: males, babies, or females
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males (then females, then babies)
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what does impedance consist of? (3 parts)
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mass, compliance, resistance
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what is the speed of sound in centimeters per second?
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34,000 cm/sec
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what is resonance?
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the place where __?___ vibrates most easily
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What is the inverse square law for intensity formula?
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10 log D1/(D2)²
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what is transfer function?
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the difference between the input and the ouput to a system
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what are standing waves?
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positions in an enclosure where the sound seems louder or softer
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what is the slope of a filter referred to as?
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rejection rate
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what determines the optimal frequency?
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the combination of mass and stiffness
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what are examples of quarter-wave resonators in the human body?
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ear canal and vocal tract
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what is fourier analysis?
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any complex, periodic wave can be broken down into a sum of simple sinusoids with differing frequencies, amplitudes, and phases
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middle ears in all mammals are primarily mass or stiffness dominated?
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stiffness (very little mass)
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If force is applied to an object with pure stiffness, the force will leave with...
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90 degree lag
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true or fasle: bends in the tract have a great effect on its resonance.
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false; little effect
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describe a helmholtz resonator.
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-hollow glass or metal bulb with a narrow tube leading out for demonstration acoustic resonance
-the fundamental oscillation is generated by blowing into the opening or tapping on the outside of the bulb.
-can put a complex sound thru this and find out which frequencies are present
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energy imparted to a tuning fork results in free vibrating motion at the _______ ______ or ______ _________.
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natural frequency or resonant frequency
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what is the difference between a square wave and a triangular wave?
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12 dB difference (roll-off) between octaves for triangualar waves; 6 dB difference for square waves
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what are the characteristics of white noise?
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-random waveform
-equal energy at all frequencies
-often created by air turbulence
-no fundamental frequency
-no harmonics
-aperiodic
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what are the characteristics of analog representation of speech?
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-continuous (every time has a value)
-simple equipment
-trouble with noise and distortion
-difficult to maintain
-inflexible
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what are the characteristics of a frequency domain?
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-requires 2 graphs: amplitude and phase
-amplitude is most important. phase is required for completeness (to recreate wave)
-time is discared (infinitely repeating signal assumed)
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what is the niquist frequency?
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sample at more than twice the highest frequency in the signal
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why do humans have less sensitivity in the low frequencies?
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because the auditory system is stiffness dominated. little mass (mass transfers low frequencies better)
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a tube that is closed on both ends has what type of wave resonators? open both ends?
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1/2 wave resonators (both)
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what weighting scale is most often used for speech signals? why?
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A scale becaus it is most representative of the MAP curve
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what are 3rd order tones also known as? and what is done to F1 or F2 to get these tones?
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-cubic difference tones
-one of them is multiplied by 2
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what is a major problem when using transducers?
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need to prevent it from tainting results (don't want mass and stiffness to influence the outcome)
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what are the rules for presenting a pure tone?
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rise time of 25 milliseconds and duration of 200 milliseconds
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true or false: the lower the roll-off value the more selecive the filter.
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false - the higher the roll-off value
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what does the inverse square law predict?
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how the energy will be reduced as you move away from the source
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