AudioGenerator

AudioGenerator[model]

generates one second of audio of a given model.

AudioGenerator[model,t]

generates t seconds of audio.

AudioGenerator[model,t,"type"]

generates audio samples of the specified "type".

Details and Options

AudioGenerator can generate different types of audio, including oscillators or noises.
Possible settings for model include:

	f	sample an arbitrary function f of time (in seconds)
	proc	generate samples from a random process proc
	tseries	generate samples from a TimeSeries tseries
	"model"	generate sample from a named function "model"

Silence:
"Silence" silence (zero) signal
Oscillators:

		{"Sin",freq,phase}	sine wave
		{"Triangle",freq,phase}	triangle wave
		{"Sawtooth",freq,phase}	sawtooth wave
		{"Square",freq,phase}	square wave
		{"Pulse",freq,phase,width}	rectangular wave using the duty cycle width
		{"Impulse",freq,phase}	impulse signal

By default, , , and are used.
The parameters freq, phase, and width can be a scalar value, a Quantity, an Audio object, a TimeSeries, or a pure function.
Noise:

		"White"	constant power spectral density
		"Pink"	power spectral density that follows
		"Brown"	power spectral density that follows
		"Blue"	power spectral density that follows
		{"Color",α}	power spectral density that follows with
		{"White",dist}	random noise with values sampled from dist
		"PeriodicRandomNoise"	sum of sinusoidal components with constant amplitude and random phase

Other:
AudioGenerator generates an audio object of "Real32" type. See the reference page for Audio for possible settings of "type".
AudioGenerator has the same options as Audio.

List of all options

Examples

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Basic Examples (3)

Generate one second of sinusoidal audio:

Generate a signal from an arbitrary function:

Generate two seconds of white noise:

Scope (17)

Basic Uses (2)

By default, 1 second of audio is generated:

Specify the duration:

Specify the duration as a time quantity:

Specify the number of samples to generate:

By default, the generated audio is of "Real32" type:

Specify a different data type:

Model Specifications (15)

Oscillators (5)

Sinusoidal oscillator at 2000 Hz:

Control the frequency of the sine wave with a function:

Visualize the spectrogram:

Control the frequency of the sine wave with another Audio object:

Visualize a spectrogram of the generated audio:

Control the frequency of the sine wave with a TimeSeries:

Generate different oscillators:

Noise Generators (5)

Generate white noise:

The values for the white noise can be sampled from a distribution:

Generate different kinds of noises:

The spectra of pink, brown, and blue noises follow a distribution of f^-α, with α equal to 1, 2, and , respectively:

The spectrum of "PeriodicRandomNoise" is perfectly flat:

Using Functions (1)

AudioGenerator supports functions of time:

Using Processes (2)

Generate audio from a noise process:

Use an audio object generated from a random process to control the amplitude of a sinusoid:

Using TimeSeries (2)

Generate an audio object from a TimeSeries:

Generate an audio object from an irregular TimeSeries:

Options (1)

SampleRate (1)

By default, SampleRate->44100 is used:

Specify a different sample rate:

Applications (8)

Noise Applications (2)

Add noise to an audio object:

Use "PeriodicRandomNoise" to test the frequency response of a linear system:

Audio Generation from Temporal Data (2)

Compare the stock price trends of two companies:

Resample and smooth the data:

Generate audio controlled by the two time series:

Use a list of TimeSeries to control the amplitudes of a list of harmonic sine waves:

Multi-Frequency Generation (3)

Generate a series of DTMF tones to simulate the dialing of a phone number:

Create a numeric keypad:

Create an auditory illusion:

Generate ramps to control frequencies and amplitudes of the oscillators:

Create frequencies that will control the oscillators. The frequencies are exactly one octave apart from each other and increase exponentially, so that pitch increases linearly:

Create amplitudes that will control the oscillators. Amplitudes go to 0 when the frequencies drop to the minimum value:

Show the relation between frequency and amplitude of one oscillator:

Combine a bank of oscillators using the created frequencies and amplitudes:

Frequency and Amplitude Modulation (1)

Generation and reconstruction of an AM signal:

Modulate the amplitude with a 22050 Hz sinusoid to shift the content at the high end of the spectrum. The result should be already inaudible for most people:

Demodulate the AM signal by multiplying the result by another sinusoid at 22050 Hz with the same phase:

Possible Issues (2)

With oscillators, the frequency should be less than or equal to half of the sample rate:

If a TimeSeries is used as an input, it needs to have numeric non-negative time stamps:

The TimeSeries needs to have a single scalar-valued path:

Interactive Examples (3)

Control frequency and phase of an oscillator:

The spectrum of AudioGenerator[{"Color",α}] follows a distribution of f^-α:

Create a complex audio signal using frequency modulation:

Neat Examples (4)

Sweep the frequency of the modulating signal:

Use the digits of Pi in base 24 to generate a sequence of frequencies for a sinusoidal oscillator:

Create a melody using DiscreteMarkovProcess:

Generate an audio signal using Morse code:

Create a function to translate a message to an audio signal using the dictionary:

Encode a string into an audio signal:

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