03 - Graphs Commmonly Used in Speech Analyses Flashcards
What is Frequency?
The number of times an object vibrates through a complete cycle
What is on the X-Axis of a Time Waveform? What is on the Y-Axis
Time
Amplitude
What is a Period?
The length of one cycle
What is the formula for Hertz?
1 sec / period in sec
1000 msec / period in msec
What is Hertz?
The number of cycles per second
How do you find the period when you know frequency (Hertz)?
1 sec / Hertz
How can pitch be determined when looking at time waveforms? (3)
By looking at the distance between the peak intervals
Low Pitch = long intervals
High Pitch = short intervals
A time waveform is a _____-_____ presentation.
Time-Amplitude
What are yes/no questions marked by on a time waveform?
The intervals become shorter as the pitch rises
What is a spectrum?
A ‘graph’ that has Frequency on the X-Axis and Amplitude on the Y-Axis
A Spectrum does NOT have a ______ component. Why?
Temporal
It displays the frequency composition at a single point in time
For what things are Spectra useful to look at?
The magnitude of various frequency components
Can Spectra be used to to study how a signal changes over time?
No
What are two types of spectra?
FFT
LPC
What does FFT stand for?
Fast Fourier Transform
An FFT decomposes the signal into its ______.
Frequency components
FFT is an ______ that greatly expedites the computations required for a more precise __________
Algorithm
Discrete Fourier Transfer
On an FFT, what is on the X-Axis? On the Y-Axis?
Frequency
Amplitude
Increasing the FFT points allows for a more _______.
Accurate display
All of the peaks on an FFT is a _______ of the __________. The peaks are ________________.
Harmonic
Glottal Buzz
Resonances of the vocal tract
What does LPC stand for?
Linear Predictive Coding
What is LPC? How?
A method that attempts to predict upcoming speech samples.
By using a weighted sum of previous samples
LPC uses _______ based on a ______________.
Estimation
Vocal Tract Model Filter
Which is more precise: FFT or LPC?
FFT
On an LPC display, what is on the X-Axis? What is on the Y-Axis?
Frequency
Amplitude
LPC is useful for looking at _______ but not _______.
Spectral peaks
Detailed frequency components
What will increasing the amount of FFT points and increasing the LPC order do?
Change the display
Does LPC show the glottal buzz?
No
Using LPC, we can construct a picture of the __________.
Shape of the vocal tract
A spectrogram analyzes sounds in ________.
Three dimensions
A spectrogram shows __________.
Spectral peaks
What is a formant? How is is shown on a spectrogram?
A resonance of the vocal tract
By darkened bars
Does a spectrogram have a time domain?
Yes
A spectrogram is the ________ of a series of _______________.
Composite
Spectra over time
What are the two types of spectrograms?
Wide band
Narrow band
A wide-band spectrogram shows _______. These are seen in the ______.
Glottal pulses
Striations
Are pulses seen in fricatives?
No
How do you get from a time waveform to a spectrogram? (3)
Sample the waveform every several milliseconds
Create an FFT
Plot these series of these spectra over time
The peaks of the FFT show up as _______ on the spectrogram.
Ridges
How do you calculate harmonics?
1 x fundamental
2 x fundamental
3x fundamental
etc.
Narrow-band spectrograms have ___________.
Detailed frequency resolution
What is a narrow-band spectrogram good for looking at? (2)
Pitch changes
Harmonic structure
What is a narrow-band spectrogram bad for looking at?
Resonances
The analysis bandwidth of a narrow-band spectrogram has to be ______ than the distance in frequency between the harmonics of the ____________.
Narrower
Voicing Source
Generally for narrow-band spectrograms, one would pick a bandwidth that is less than the speaker’s ____________.
Fundamental Frequency
What is the analysis bandwidth of a narrow-band spectrogram?
45 Hz
A narrow-band spectrogram captures the ________.
Harmonics
What type of spectrogram is ideal for analyzing the formant structure?
Wide Band
Wide band spectrograms span over a wider ________ than narrow band spectrograms.
Range of frequencies
What type of spectrogram has vertical striations?
Wide Band
What type of spectrogram has horizontal striations?
Narrow Band
What are wide band spectrograms good for looking at?
Resonances
What are wide band spectrograms bad for looking at? (2)
Pitch changes
Harmonic structure
In a wide band spectrogram, the analysis bandwidth has to be ______ than the ______________ between the harmonics of the voicing source.
Larger
Distance in frequency
Generally in a wide band spectrogram, one would pick an analysis bandwidth that is ________ than the speaker’s _____________.
Larger
Fundamental frequency
What is the analysis bandwidth of a wide band spectrogram?
300 Hz
In what kind of spectrogram are f0 changes visible?
Narrow Band
What kind of spectrogram shows harmonics? How?
Narrow band
Vertical Stripes
What kind of spectrogram shows resonances? How?
Wide band
Horizontal bands
What kind of spectrogram shows glottal pulses? How
Wide band
Vertical striations
What is a pitch contour?
It tracks fundamental frequency over time
What kind of spectra is this?
FFT
What kind of spectra is this?
LPC
This is an example of a _________. This information is used to construct a _______.
Spectrum
Label the Following:
A = Waveform
B = Spectrograph
C = Pitch Contour
Label the Following:
1 = Time Wave Form
2 = Spectrum (FFT_
3 = Narrow-Band Spectrograph
4 = Wide-Band Spectrograph
