Quiz 5 Flashcards
Friday October 4 - Wednesday October 9
What are complex waves?
All speech sounds
Made up of multiple sine waves at different amplitudes
What is a periodic wave?
A sine wave that repeats itself
E.g., vowels, sonorants and prevoicing
What is an aperiodic wave?
A wave where there is no repeating pattern
E.g, voiceless fricatives
What are combination waves?
A wave that has both period and aperiodic signals
E.g., voiced fricatives
How do you get from a complex wave to a (power) spectrum?
Make a list of the sine waves in a complex wave using Fourier transformation
display the individual frequencies and amplitudes in a graph
What is fundamental frequency?
The first harmonic (f0), represents the pitch
What does F1 represent?
Vowel height
Inverse relationship
The higher F1 the lower the vowel
What does F2 represent?
Backness
Front vowels will have a high F2
What does F3 represent?
Roundness
Unrounded vowels will have a higher F3
How do you get from a spectra to a spectrogram?
Find and shade the peaks
Rotate the spectrum 90 degrees counterclockwise
What is an analog signal?
A continuous, gradual signal
Possible value at every point in time
E.g., height
What is a digital signal?
Discrete signal that has separate amplitude values from specific points in time
What is the analog to digital process?
Converts analog signals into digital ones
Involves sampling
What is sampling rate?
Deciding which values should be kept and which should be dumped
Explain Nyquist’s theory
In order to regenerate a cycle with no loss of information it needs to be sampled at 2x the frequency
What is aliasing?
When you do not take at least 2 samples per cycle
Makes your recording trash
What is quantization?
How frequently you want to sample data
Size you want the values to be
What is Fourier transformation?
The mathematical analysis of complex wave properties
Tries to find the degree of correlation
Define source filter theory
Acoustic speech signals can be seen as a source signal filtered with the resonance in the cavities of the vocal tract
What is the source?
The vocal tract
Harmonics are connected to
What is the filter
The supra laryngeal cavity
All formants are a property of the filter
