AI4GA Unit 2, Module 2.2 Waveforms and Spectrogram Vocabulary

Amplitude

• A band in a speech spectrogram containing relatively high energy. Normal speech is composed of several of these.

• The rate of variation in a periodic signal. For sound this corresponds to pitch. Measured in Hertz, or cycles per second.

• The size of a signal. For sound, it is the loudness. For electrical signals it's the size of the voltage change

• Rhythmic variation back and forth between two extremes. Sound is this in air pressure.

Formant

• The size of a signal. For sound, this is the loudness. For electrical signals it's the size of the voltage change.

• A frequency band in speech spectrogram containing relatively high energy. Normal speech is composed of several of these.

• The distance between notes when one is twice or half the frequency of the other. A above middle C (440 Hz) and A below middle C (220 Hz) are one of these apart.

• A visualization of the energy in a signal at various frequencies, over time. This is the first step in speech recognition.

Waveform

• A signal represented as an amplitude over time. Sine waves are correspond to simple tones while speech is more complex.

• A smoothly varying line with constant amplitude and frequency. The shape follows the sine function.

• The rate of variation in a periodic signal. For sound this corresponds to pitch. It is measured in Hertz, or cycles per second.

• A visualization of the energy in a signal at various frequencies, over time. This is the first step in speech recognition.

Octave

• The rate of variation in a periodic signal. For sound, this corresponds to pitch. It is measured in Hertz, or cycles per second.

• An integer multiple of a frequency, e.g., A above middle C is 440 Hz, and its second and third are at 880 and 1320 Hz.

• Rhythmic variation back and forth between two extremes. Sounds measured based on air pressure.

• The distance between notes when one is twice or half the frequency of the other. A above middle C (440 Hz) and A below middle C (220 Hz) are one of these apart.

Frequency

• Rhythmic variation back and forth between two extremes. 

• An integer multiple of a frequency, e.g., A above middle C is 440 Hz, and its second and third harmonics are at 880 and 1320 Hz.

• A smoothly varying waveform with constant amplitude and frequency. The shape of the wave follows this function. 

• The rate of variation in a periodic signal. For sound this corresponds to pitch. It is measured in Hertz, or cycles per second. 

Harmonic

• A device for measuring sound in electrical signals. A microphone converts sound to voltage, allowing it to be seen by this device.

• An integer multiple of a frequency, e.g., A above middle C is 440 Hz, and its second and third harmonics are at 880 and 1320 Hz

• The size of a signal. For sound, it is the loudness. For electrical signals, it’s the size of the voltage change.

• A smoothly varying waveform with constant amplitude and frequency. The shape of the wave follows this function. 

Hertz (Hz)

• The rate of variation in a periodic signal. For sound this corresponds to pitch. It is measured in Hertz, or cycles per second. 

• A unit of frequency corresponding to cycles per second. The note A above middle C is 440 of this (or cycles per second). 

• This distance between notes when one is twice or half the frequency of the other. A above middle C (440 Hz) and A below middle C (220 Hz) are one octave apart.

• Rhythmic variation back and forth between two extremes. 

Oscillation

• A visualization of the energy in a signal at various frequencies, over time. This recognizes the first step in speech recognition. 

• A frequency band in a speech spectrogram containing relatively high energy. Normal speech is composed of several of these. 

• A visualization of the energy in a signal at various frequencies, over time. This recognizes the first step in speech recognition. 

• Rhythmic variation back and forth between two extremes. 

Oscilloscope

• A device for measuring sound in electrical signals. A microphone converts sound to voltage, allowing it to be seen by this device.

• A frequency band in a speech spectrogram containing relatively high energy. Normal speech is composed of several of these.

• A smoothly varying waveform with constant amplitude and frequency. The shape of the wave follows this function. 

• A visualization of the energy in a signal at various frequencies, over time. This recognizes the first step in speech recognition. 

Sine Wave

• Rhythmic variation back and forth between two extremes. 

• A unit of frequency corresponding to cycles per second. The note A above middle C is 440 of this (or cycles per second). 

• A smoothly varying waveform with constant amplitude and frequency. The shape of the wave follows this function. 

• The rate of variation in a periodic signal. For sound this corresponds to pitch. It is measured in Hertz, or cycles per second.