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Variable Attenuator

Model variable attenuator

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  • Library:

  • RF Blockset / Circuit Envelope / Elements

  • Variable Attenuator block

Description

TheVariable Attenuatorblock attenuates the signal power by a given factor known asInsertion Lossin dB. Using theVariable Attenuatorblock, you can vary the attenuation of the input Simulink®signal during simulation. Commonly, the block matches the impedance of the RF circuit at the input and output ports. You can use attenuators to dampen the power of the incoming signal to protect RF circuits.

Variable Attenuatorblock mask icons are dynamic and show the current state of the applied noise parameter. This table shows you how the icons on this block vary based on the state of theSimulate noiseparameter on the block.

Simulate noise:on Simulate noise:off

Variable Attenuator block icon with Simulate noise is set to on.

Variable Attenuator block icon with Simulate noise is set to off.

Ports

Input

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金宝appSimulink控制信号，指定为标量。该控制信号是Insertion Lossin dB.

Data Types:double

Parameters

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Lowest value of insertion loss or attenuation to apply to the signal, specified as a scalar in dB.

Highest value of insertion loss or attenuation to apply to the signal, specified as a scalar in dB.

衰减器的输入阻抗,指定为一个scalar in ohms.

衰减器的输出阻抗，在欧姆中指定为标量。

Select this parameter to simulate thermal noise in the attenuator. You must selectSimulate noisein theConfigurationblock.

This parameter inserts a current noise source with the single-sided power density of4kT/RA2/Hz, where:

  • T是Temperatureparameter in theConfigurationblock. Units are in degrees Kelvin.

  • kis the Boltzmann constant.

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

Model Examples

Vary Attenuation of Signal During Simulation

Vary Attenuation of Signal During Simulation

Use the Variable Attenuator block to attenuate a 20 dB constant signal. Use the Repeating Sequence Stair block as a Simulink control signal to vary the attenuation of the signal. In this model, the signal attenuation varies between 5 and 10 dB during simulation. To see the variation in attenuation, open and run the model.
Open Model

Version History

Introduced in R2016b

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Behavior changed in R2021b

See Also

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