Posted on by Debanka

Noise Generator

The Noise Generator audio object generates noise audio samples scaled by a specified gain value.

Use Case: This object can be deployed to generate noise of different types with different gain values.

Noise Generator Properties

Below table describes about the Noise Generator audio object properties and functionality.

Properties Description
# of Audio Out Enter the number of output channels.

  • Range: 1 to 255
  • Data type: Unsigned Short
  • The default value is set to 1.
Display Name Display the name of the Noise Generator audio object in signal flow design. It can be changed based on the intended usage of the object.
Object Mode Noise generator operates in one of the following two modes.

  • WhiteNoise
  • PinkNoise
  • Pro-Prbs
  • Pro-Lcg

Mode

The Noise generator object supports four different modes of operation.

Mode Description
White Noise (Mode 0) The White noise is generated based on the initial seed value. The initial seed value is multiplied by a scale factor to get white noise. This is the default mode.
Pink Noise (Mode 1) To generate pink noise, white noise is generated first and pink filter is applied over that.
Pro-Prbs (Mode 2) The Pro-Prbs (Pseudo Random Bit Sequence) mode generates white and pink noise that can be chosen through tuning parameter.

  • White Noise Generation: In this mode pseudo random binary sequence generator is used to generate the white noise signal. It is a deterministic algorithm.
  • Pink Noise Generation: In this mode Paul kellet’s algorithm is used to generate Pink noise signal.
Pro-Lcg (Mode 3) The Pro-Lcg (Linear Congruential Generator) mode generates white and pink noise that can be chosen through tuning parameter.

  • White Noise Generation: In this mode “Minimal” random number generator of Park and Miller with Bays-Durham shuffle method is used to generate white noise.
  • Pink Noise Generation: In this mode the White Noise that is generated through the linear congruential method is passed through Pink filter 0 and Pink filter 1 to generate the pink noise. The pink noise is passed through the HPF and LPF filters to limit the frequency spectrum to 20 to 20 kHz.

In all the modes, the gain (Noise Level) is in dB scale ranging from -128 dB to 0 dB. The same gain value applies to all channels of the Noise Generator object. It also exposes that same variable for control purposes.

Additional Parameters

There are no additional parameters available for Noise Generator audio object .

Tuning Parameters

Below table describes the tuning parameters of Noise Generator audio object.

For White Noise and Pink Noise mode

Parameter Description Unit Data Type Default Range
Noise Level Generates noise in output channel with gain as tuneable. db Float -60 -128 to 0

For Pro-Prbs and Pro-Lcg modes

Parameter Description Unit Data Type Default Range
Noise Level Generates noise in output channel with gain as tuneable. db Float -100 -128 to 0
Noise Type Generates white or pink noise in output channel with noise type as a tuneable parameter.
This is applicable only for Mode 2 (Pro-Prbs) and Mode 3 (Pro-Lcg).The noise type parameter allows the user to choose white noise or pink noise dynamically.		 None Float 1 0 (White)

or

1 (Pink)

Control Interface

The Noise Generator object has one control input – Gain (Noise Level) ranging from -128 dB to 0 dB and this value is applicable to all the channels. This control input is available in all the four modes.

This  audio object does not have any control output.