physconst

Physical constants

Syntax

const = physconst(name)

Description

const = physconst(name) returns the value of the physical constant const specified by the name argument.

Examples

Convert Frequency to Wavelength

Determine the wavelength of a 1 GHz electromagnetic wave.

freq = 1e9;
lambda = physconst('LightSpeed')/freq

lambda = 0.2998

Thermal Noise Power

Determine the thermal noise power per unit bandwidth in the in-phase (I) and quadrature (Q) channels of a receiver. Specify a receiver temperature of 290 K.

T = 290;
k = physconst('Boltzmann');

Compute the noise power per unit bandwidth, split evenly between the I and Q channels. Units are in dB.

Noise_power = 10*log10(k*T/2)

Noise_power = -206.9855

Input Arguments

name — Name of physical constant

'LightSpeed' | 'Boltzmann' | 'EarthRadius'

Name of physical constant, specified as 'LightSpeed', 'Boltzmann', or 'EarthRadius'. See Physical Constants for a list of values for physical constants used in Phased Array System Toolbox™.

Example: 'LightSpeed'

Output Arguments

const — Value of physical constant

real-valued scalar

Value of physical constant, returned as a real-valued scalar. All values are in SI units.

More About

Physical Constants

This table lists the supported constants and their values in SI units.

Constant	Description	Value
'LightSpeed'	Speed of light in vacuum	299,792,458 m/s. Most commonly denoted by c.
'Boltzmann'	Boltzmann constant relating kinetic energy to temperature	$$1.\text{3806504}\times {10}^{-23}$$ J/K. 2006 NIST value, most commonly denoted by k.
'EarthRadius'	Mean radius of the Earth	6,371,000 m

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

The function does not support variable-size inputs.

Version History

Introduced in R2011a