Receiver Thermal Noise

Apply receiver thermal noise to complex signal

Library:
Communications Toolbox / RF Impairments

Description

The Receiver Thermal Noise block applies receiver thermal noise to a complex signal. The block simulates the effects of thermal noise on a complex signal. The Specification method parameter enables specification of thermal noise based on noise temperature, noise figure, or noise factor.

Ports

Input

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`In1` — Complex signal
scalar | column vector

Complex signal, specified as a scalar or column vector.

Data Types: double | single
Complex Number Support: Yes

Output

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`Out1` — Output signal
scalar | column vector

Output signal, returned as a scalar or column vector. This output is the same dimension and data type as the input signal.

Parameters

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`Specification method` — Thermal noise specification method
`Noise temperature` (default) | `Noise figure` | `Noise factor`

Thermal noise specification method, specified as one of these options.

Noise temperature specifies the noise in degrees K.
Noise figure specifies the added receiver noise in dB relative to an input noise temperature of 290 K. The noise figure is the decibel equivalent of the noise factor.
Noise factor specifies the added receiver noise relative to an input noise temperature of 290 K. The noise factor is the linear equivalent of the noise figure.

`Noise temperature (K)` — Noise temperature
`290` (default) | scalar

Noise temperature in degrees K, specified as a scalar.

Dependencies

To enable this parameter, set the Specification method parameter to Noise temperature.

`Noise figure (dB)` — Receiver noise figure
`3.0103` (default) | scalar

Receiver noise figure in dB relative to a noise temperature of 290 degrees K, specified as a scalar.

Note

This parameter specifies the noise contribution of the receiver circuitry only. To add the effects of antenna noise, select the Add 290K antenna noise parameter.

Dependencies

To enable this parameter, set the Specification method parameter to Noise figure.

`Noise factor` — Receiver noise factor
`2` (default) | scalar

Receiver noise factor relative to a noise temperature of 290 degrees K, specified as a scalar.

Note

This parameter specifies the noise contribution of the receiver circuitry only. To add the effects of antenna noise, select the Add 290K antenna noise parameter.

Dependencies

To enable this parameter, set the Specification method parameter to Noise factor.

`Add 290K antenna noise` — Option to add 290 degrees K antenna noise
`off` (default) | `on`

Select this parameter to add 290 degrees K antenna noise to the signal.

Dependencies

To enable this parameter, set the Specification method parameter to Noise factor or Noise factor.

`Initial seed` — Initial seed value
`67987` (default) | scalar

Initial seed value for the random number generator, specified as a scalar.

Model Examples

Apply Receiver Thermal Noise to QAM Modulated Signal

The model applies receiver thermal noise to a 16-ary quadrature amplitude modulation (16-QAM) signal and shows the effect of applying receiver thermal noise using the noise figure specification method. To show the receiver thermal noise in a constellation diagram of the 16-QAM signal, the noise figure is set to a level of 10 dB.

RF Satellite Link

A satellite link, using the blocks from the Communications Toolbox™ to simulate the following impairments: Memoryless nonlinearity

Add RF Impairments to DQPSK Signal

This model applies RF impairments to a signal modulated by differential quadrature phase shift keying (DQPSK). To demonstrate and visualize the RF impairments, levels applied in this model are exaggerated and not representative of typical levels for modern radios.

Block Characteristics

Data Types	`double` \| `single`
Multidimensional Signals	`no`
Variable-Size Signals	`no`

Algorithms

Wireless receiver performance is often expressed as a noise factor or figure. The noise factor is defined as the ratio of the input signal-to-noise ratio, S_i/N_i to the output signal-to-noise ratio, S_o/N_o, such that

$F = \frac{S_{i} / N_{i}}{S_{o} / N_{o}} .$

Given receiver gain G and receiver noise power N_ckt, the noise factor can be expressed as

$\begin{matrix} F = \frac{S_{i} / N_{i}}{G S_{i} / (N_{c k t} + G N_{i})} \\ = \frac{N_{c k t} + G N_{i}}{G N_{i}} . \end{matrix}$

The IEEE defines the noise factor assuming that noise temperature at the input is T₀, where T₀ = 290 K. The noise factor is then

$\begin{matrix} F = \frac{N_{c k t} + G N_{i}}{G N_{i}} \\ = \frac{G k B T_{c k t} + G k B T_{0}}{G k B T_{0}} \\ = \frac{T_{c k t} + T_{0}}{T_{0}} . \end{matrix}$

T_ckt is the equivalent input noise temperature of the receiver and is expressed as

$T_{c k t} = T_{0} (F - 1) .$

The overall noise temperature of an antenna and receiver, T_sys, is

$T_{s y s} = T_{a n t} + T_{c k t},$

where T_ant is the antenna noise temperature.

The noise figure, NF, is the dB equivalent of the noise factor and can be expressed as

$N F = 10 \log_{10} (F) .$

Documentation

Receiver Thermal Noise

Description

Ports

Input

`In1` — Complex signal
scalar | column vector

Output

`Out1` — Output signal
scalar | column vector

Parameters

`Specification method` — Thermal noise specification method
`Noise temperature` (default) | `Noise figure` | `Noise factor`

`Noise temperature (K)` — Noise temperature
`290` (default) | scalar

Dependencies

`Noise figure (dB)` — Receiver noise figure
`3.0103` (default) | scalar

Dependencies

`Noise factor` — Receiver noise factor
`2` (default) | scalar

Dependencies

`Add 290K antenna noise` — Option to add 290 degrees K antenna noise
`off` (default) | `on`

Dependencies

`Initial seed` — Initial seed value
`67987` (default) | scalar

Model Examples

Apply Receiver Thermal Noise to QAM Modulated Signal

RF Satellite Link

Add RF Impairments to DQPSK Signal

Block Characteristics

Algorithms

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

See Also

Blocks

Objects

Communications Toolbox Documentation

Support

Documentation

Receiver Thermal Noise

Description

Ports

Input

In1 — Complex signal scalar | column vector

Output

Out1 — Output signal scalar | column vector

Parameters

Specification method — Thermal noise specification method Noise temperature (default) | Noise figure | Noise factor

Noise temperature (K) — Noise temperature 290 (default) | scalar

Dependencies

Noise figure (dB) — Receiver noise figure 3.0103 (default) | scalar

Dependencies

Noise factor — Receiver noise factor 2 (default) | scalar

Dependencies

Add 290K antenna noise — Option to add 290 degrees K antenna noise off (default) | on

Dependencies

Initial seed — Initial seed value 67987 (default) | scalar

Model Examples

Apply Receiver Thermal Noise to QAM Modulated Signal

RF Satellite Link

Add RF Impairments to DQPSK Signal

Block Characteristics

Algorithms

Extended Capabilities

C/C++ Code Generation Generate C and C++ code using Simulink® Coder™.

See Also

Blocks

Objects

Communications Toolbox Documentation

Support

`In1` — Complex signal
scalar | column vector

`Out1` — Output signal
scalar | column vector

`Specification method` — Thermal noise specification method
`Noise temperature` (default) | `Noise figure` | `Noise factor`

`Noise temperature (K)` — Noise temperature
`290` (default) | scalar

`Noise figure (dB)` — Receiver noise figure
`3.0103` (default) | scalar

`Noise factor` — Receiver noise factor
`2` (default) | scalar

`Add 290K antenna noise` — Option to add 290 degrees K antenna noise
`off` (default) | `on`

`Initial seed` — Initial seed value
`67987` (default) | scalar

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.