COMD 5070 Exam 3 UPDATED ACTUAL
Exam Questions and CORRECT Answers
What is science? (4 features of the scientific method) - CORRECT ANSWER - 1.
Empirical
2. Deterministic
3. Predictive
4. Parsimonious
Empirical - CORRECT ANSWER - based on data
Deterministic - CORRECT ANSWER - Obeys the laws of physics
Predictive - CORRECT ANSWER - cause-and-effect relationships
Parsimonious - CORRECT ANSWER - use the simplest explanation possible
semitone - CORRECT ANSWER - smallest distance between two pitches (half step)
How many semitones are in one octave? - CORRECT ANSWER - 12
How many semitones are in two octaves? - CORRECT ANSWER - 24
If you want to go up one octave, you ______ the frequency. But if you want to go down an
octave, you _____ the frequency. - CORRECT ANSWER - Double, halve
how many hertz is in an octave? - CORRECT ANSWER - There's no fixed number of
hertz between octaves
,sampling rate - CORRECT ANSWER - frequency with which numbers are stored or
written down to represent the analog signal that you're sampling
- measured in Hz (how many samples stored in one second)
Nyquist frequency - CORRECT ANSWER - half the sample rate
represents the highest frequency that your recording can accurately reproduce when you play it
back
ex. if you want to go up to 10 kHz, you have to double that number to choose a sample frequency
sampling theorem - CORRECT ANSWER - gives the minimum sampling rate which
allows the original signal to be reconstructed perfectly
aliasing - CORRECT ANSWER - one sound is misrepresented as another
another concept to think about when choosing a sample rate
if you record a signal at a too-slow sample rate, there will be things happening in the original
signal that occur between the samples or snapshots you take (inaccurately records the original
signal)
filtering before digitizing prevents this (using a low-pass filter for anti-aliasing)
Example sampling: If the data is 5 kHz, you should sample at ______ kHz. - CORRECT
ANSWER - 10
How does sampling rate relate to playback quality? - CORRECT ANSWER - The more
samples you take, the better chance you have of representing the original signal.
what does a filter do? - CORRECT ANSWER - removes certain things you don't want
allow you to be selective in what frequencies come through
filter types - CORRECT ANSWER - high pass
, low pass
band pass
band reject
high pass filter - CORRECT ANSWER - Only allows high frequencies to pass through.
low pass filter - CORRECT ANSWER - Only allows low frequencies to pass through.
blocks high frequencies
band reject filter - CORRECT ANSWER - Rejects or attenuates a band of frequencies, but
allows high and low frequencies to pass through.
band pass filter - CORRECT ANSWER - a specified range of frequencies between the
low- and high-pass cutoff frequencies to be passed effectively.
time domain display - CORRECT ANSWER - x-axis: time
y-axis: amplitude
waveform
represents sound directly
air pressure changes over time
frequency domain display - CORRECT ANSWER - x-axis: frequency
y-axis: power or amplitude
spectrum
shows individual harmonic components
also shows the relative proportions of each component
- peaks represent the individual harmonic components represented in this voice signal
types of spectra - CORRECT ANSWER - line spectrum
Exam Questions and CORRECT Answers
What is science? (4 features of the scientific method) - CORRECT ANSWER - 1.
Empirical
2. Deterministic
3. Predictive
4. Parsimonious
Empirical - CORRECT ANSWER - based on data
Deterministic - CORRECT ANSWER - Obeys the laws of physics
Predictive - CORRECT ANSWER - cause-and-effect relationships
Parsimonious - CORRECT ANSWER - use the simplest explanation possible
semitone - CORRECT ANSWER - smallest distance between two pitches (half step)
How many semitones are in one octave? - CORRECT ANSWER - 12
How many semitones are in two octaves? - CORRECT ANSWER - 24
If you want to go up one octave, you ______ the frequency. But if you want to go down an
octave, you _____ the frequency. - CORRECT ANSWER - Double, halve
how many hertz is in an octave? - CORRECT ANSWER - There's no fixed number of
hertz between octaves
,sampling rate - CORRECT ANSWER - frequency with which numbers are stored or
written down to represent the analog signal that you're sampling
- measured in Hz (how many samples stored in one second)
Nyquist frequency - CORRECT ANSWER - half the sample rate
represents the highest frequency that your recording can accurately reproduce when you play it
back
ex. if you want to go up to 10 kHz, you have to double that number to choose a sample frequency
sampling theorem - CORRECT ANSWER - gives the minimum sampling rate which
allows the original signal to be reconstructed perfectly
aliasing - CORRECT ANSWER - one sound is misrepresented as another
another concept to think about when choosing a sample rate
if you record a signal at a too-slow sample rate, there will be things happening in the original
signal that occur between the samples or snapshots you take (inaccurately records the original
signal)
filtering before digitizing prevents this (using a low-pass filter for anti-aliasing)
Example sampling: If the data is 5 kHz, you should sample at ______ kHz. - CORRECT
ANSWER - 10
How does sampling rate relate to playback quality? - CORRECT ANSWER - The more
samples you take, the better chance you have of representing the original signal.
what does a filter do? - CORRECT ANSWER - removes certain things you don't want
allow you to be selective in what frequencies come through
filter types - CORRECT ANSWER - high pass
, low pass
band pass
band reject
high pass filter - CORRECT ANSWER - Only allows high frequencies to pass through.
low pass filter - CORRECT ANSWER - Only allows low frequencies to pass through.
blocks high frequencies
band reject filter - CORRECT ANSWER - Rejects or attenuates a band of frequencies, but
allows high and low frequencies to pass through.
band pass filter - CORRECT ANSWER - a specified range of frequencies between the
low- and high-pass cutoff frequencies to be passed effectively.
time domain display - CORRECT ANSWER - x-axis: time
y-axis: amplitude
waveform
represents sound directly
air pressure changes over time
frequency domain display - CORRECT ANSWER - x-axis: frequency
y-axis: power or amplitude
spectrum
shows individual harmonic components
also shows the relative proportions of each component
- peaks represent the individual harmonic components represented in this voice signal
types of spectra - CORRECT ANSWER - line spectrum
