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51 Cards in this Set
- Front
- Back
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It's not the _______ itself that is digital - it's the way we ________ the sound _________. Digital __________ tends to make a _________, ________ quality copy of the sound.
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sound
store signal storage clearer higher |
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Music is stored in _________ form but it is played back in _________ form.
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numeric
analog |
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What does analog mean?
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analogy - one phenomenon represented by another
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The microphone's sound signal that travels through a wire is analogous to the __________ __________ coming through the ______ that reaches the microphone.
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sound pressure
air |
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The microphone voltage represents sound:
large positive voltage = ____ __________ large negative voltage = ____ rarefaction This is because a microphone is a ___________. |
air compression
air rarefaction transducer |
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The sound pressure ____________ that reach the microphone are ___________ by the microphone into a __________ changing ____________ signal.
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vibrations
converted rapidly electrical |
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Any change in ______ ____________ that causes the internal mechanism of the microphone to move will result in a _____________ change in __________ at the same _____________ and in an ___________ proportional to the ______ of the sound that came in.
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air pressure
commensurate voltage frequency amplitude size |
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What is the most important characteristics of analog signals?
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continuous in time and amplitude
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If you zoom in on continuous analog signals at any level of detail you would not find what?
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gaps in the recording
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An analog recording can represent an ___________ number of points in _______ and an ___________ number of __________ _________ between the minimum and the maximum.
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infinite
time infinite amplitude values |
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An analog signal cannot be fully represented by what?
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a table of numbers
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Digital recordings are ___________ in time and amplitude. They are made up of a ________ of __________ numbers recorded in one long ________. The numbers represent ___________ over time.
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discrete
series separate string snapshots |
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The numbers from digital signals have _________ ___________. You could fully _________ them by a ________ of numbers.
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finite precision
represent table |
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What are the limitations of digital recordings?
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there are "unknowns" between the points
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To convert analog to digital, the analog signal from the wire has to be ____________ to ___________ in order to be used by a computer, etc.
ADC = ? DAC = ? |
converted
numbers analog to digital digital to analog |
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What is the frequency with which the numbers are recorded to represent amplitude values of the sound you are recording?
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sampling rate
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What is also described as the frequency of snapshots in a digital recording?
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sampling rate
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Sample rate is specified in?
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Hz
Ex: 10 snapshots per second would be a 10 Hz recording |
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In a digital recording, a higher sampling rate gives better __________, but it also requires ________ _______ which require more _________ usage, more _______ _________, and more ____________ time for computation.
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fidelity
bigger files memory disk space processing |
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What represents the highest frequency you can record and then accurately play back?
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Nyquist frequency
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You sample at ______ the rate of the __________ frequency.
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twice
highest |
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What is the sample rate for CDs?
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44,100 samples per second
44.1 Hz |
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When choosing a sample rate, you should always ____ on the side of ________. You can always ____________ later.
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err
detail downsample |
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All sounds originate with ___________. ____________ characteristics determine the __________ of the sound. Speech production has many ________ of __________.
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movement
movement nature degrees freedom |
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Acoustic analysis is _____________. We can draw __________ from the ___________ in the acoustic signal about ____________ that ___________ the sound.
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noninvasive
inferences changes movements generated |
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What indicates disordered vocal fold movement?
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a disordered voice
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What indicates abnormal movement of the articulators?
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distorted/imprecise articulation
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A disordered voice is a change in what?
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sound source
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Distorted/imprecise articulation is a change in what?
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filter
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What are the limitations of acoustic analysis?
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The acoustic patterns reflect the vocal tract movements with some ambiguity and acoustics cannot reveal all details of movement.
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The idea that the same sound can be produced in several physical ways is what?
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motor equivalence
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There are some limitations in getting __________ physical _____________ of articulatory __________ from a microphone signal because there are __________ different ____________ working at once to ___________ to the way that ________ was made.
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calibrated
measures behavior several structures contribute sound |
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What allows us to be selective in which frequencies we keep for analysis?
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speech filter
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Which type of filter allows high frequencies through and holds back lower frequencies?
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high pass
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What type of filter allows low frequencies through and holds back higher frequencies?
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low pass
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What type of filter allows a middle band of frequencies through and holds back both higher and lower frequencies?
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band pass
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What type of filter holds back a middle band of frequencies and allows both higher and lower frequencies through?
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band reject
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Why do we use a band reject filter?
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to remove unwanted noise
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With a band reject filter, we remove such a ________ band that it doesn't really have any impact on the ________ of speech. If you were to use a _________ band reject filter, there would be some ______________ for the _______ of speech because you would be deleting a number of ____________ that would be important for speech _____________.
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narrow
quality wider consequences quality frequencies perception |
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Why do we use a band-pass filter?
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to show frequency and its energy
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Why were band-pass filters used in the early days of speech analysis?
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They helped us understand which frequencies were present in the speech sample.
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A band-pass filter measured the ________ of each filter and showed the ________ at each ____________ level. This yielded a _______ idea of the ingredients list of a certain sound.
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output
energy frequency crude |
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Why did the early pioneers in acoustic analysis like the different band-pass filters?
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Helped to understand whether the energy was in the lower, middle, or higher frequency range for a certain sound.
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What type of filter gives information about the strength of the different frequencies in a given sound?
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band-pass
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What type of filter allows movement from low to high frequencies as the frequency was being analyzed?
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adjustable filter
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Acoustic analysis ________ up complex sound into its ___________ sounds.
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splits
component |
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What makes one sound different from another (alter its quality perceptually)?
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relative proportions of components
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Altered proportions = _________ __________. If you adjusted the ___________ or ___________ of frequencies, you get a different sound.
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altered quality
amplitude proportion |
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Who came up with a way of analyzing complex signals and decomposing them or splitting them into a series of component frequencies?
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Joseph Fourier
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Fourier's great contribution was to show that even _________ _________ can be __________ _________ into their individual __________ components.
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complex sounds
broken down sinusoid |
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All periodic sounds are made of a combination of ______ ______ (component frequencies). These individual sine waves may vary by: _________, _________ ________, and ___________.
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sine waves
amplitudes phase angles frequencies |
