Noise

Model noise using current or voltage noise source in RF systems

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Libraries:
RF Blockset / Circuit Envelope / Sources

Description

Use the Noise block to model noise as a ideal current or voltage source for blocks. When you use a Noise to simulate noise in an RF model, also select the Simulate noise check box in the Configuration block. Otherwise, the model simulates without noise. The Noise block does not depend on the Temperature parameter in the Configuration.

Noise block mask icons are dynamic and show the current type of source. This table shows you how the icons on this block vary based on the type of source you set on the Source type parameter on the block.

Source type: Ideal voltage	Source type: Ideal current

Examples

Explicitly Simulate Resistor Thermal Noise

Use the Noise block to calculate the classic thermal noise floor, kT, for a matched resistor circuit. Model configuration is as follows:

Open Script

Parameters

Source type — Noise type

Ideal voltage (default) | Ideal current

Noise type, specified as Ideal voltage or Ideal current.

Noise distribution — Noise distribution type

White (default) | Piece-wise linear | Colored

Noise distribution type, specified as White, Piece-wise linear, or Colored.

Noise power spectral density — Single-sided noise power spectral distribution (PSD)

0 (default)

Single-sided noise power spectral distribution (PSD), specified as:

• White, spectral density is a single non-negative value. The power value of the noise depends on the bandwidth of the carrier and the bandwidth depends on the time step. This is an uncorrelated noise source.

• Piece-wise linear, spectral density is a vector of values [p_i]. For each carrier, the noise source behaves like a white uncorrelated noise. The power of the noise source is carrier-dependent.

• Colored, depends on both carrier and bandwidth. This is a correlated noise source.

When Source type is set to:

• Ideal voltage, spectral density units are V²/Hz.

• Ideal Current, spectral density units are A²/Hz.

Frequencies — Frequencies for piece-wise linear noise distribution

0 Hz (default) | vector of non-negative frequencies | Hz | kHz | MHz | GHz

Frequencies for piece-wise linear noise distribution, specified as vector of non-negative frequencies.

Ground and hide negative terminals — Ground RF circuit terminals

on (default) | off

Select this option to internally ground and hide the negative terminals. To expose the negative terminals, clear the option. By exposing these terminals, you can connect them to other parts of your model.

By default, this option is selected.

Version History

Introduced in R2010b

R2021b: Noise block icon updated

Starting in R2021b, the Noise block icon is now updated. When you open a model created before R2021b containing a Noise block, the software replaces the block icon with the R2021b version.