This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Click here to see
To view all translated materials including this page, select Country from the country navigator on the bottom of this page.

Free Space Path Loss

Reduce amplitude of input signal by amount specified


RF Impairments


The Free Space Path Loss block simulates the loss of signal power due to the distance between transmitter and receiver. The block reduces the amplitude of the input signal by an amount that is determined in either of two ways:

  • By the Distance (km) and Carrier frequency (MHz) parameters, if you specify Distance and Frequency in the Mode field

  • By the Loss (dB) parameter, if you specify Decibels in the Mode field

This block accepts a column vector input signal. The input signal to this block must be a complex signal.



Method of specifying the amount by which the signal power is reduced. The choices are Decibels and Distance and Frequency.


The signal loss in decibels. This parameter appears when you set Mode to Decibels. The decibel amount shown on the mask is rounded for display purposes only.


Distance between transmitter and receiver in kilometers. This parameter appears when you set Mode to Distance and Frequency.

Carrier frequency (MHz)

The carrier frequency in megahertz. This parameter appears when you set Mode to Distance and Frequency.


The model below illustrates the effect of the Free Space Path Loss block with the following parameter settings:

  • Mode is set to Distance and Frequency.

  • Distance (km) is set to 0.5

  • Carrier frequency (MHz) is set to 180

Extended Capabilities

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

Introduced before R2006a