Phased Array System Toolbox™ software almost exclusively uses SI base and derived units to measure physical quantities. The software does not provide any utilities for converting SI base or derived units to other systems of measurement.
Angles are an exception to the use of SI base and derived units. All angles in Phased Array System Toolbox software are specified in degrees. SeeSpherical Coordinatesfor an explanation of the angles used in the software. There are two utility functions for converting angles from radians to degrees and degrees to radians:rad2deg
anddeg2rad
.
To accurately model and simulate phased array systems, it is necessary to account for gains and losses in power incurred at various stages of processing. In Phased Array System Toolbox software, gains and losses are specified in decibels (dB). Signal to noise ratios (SNRs) and the receiver noise figure are also expressed in dB. Power in dB is related to power in watts,P, by:
There are two utility functions for converting between dB and power:db2pow
andpow2db
, and two utility functions for converting between magnitude and dB:db2mag
andmag2db
.
Modeling and simulating phased array systems requires that you specify values for several physical constants. For example, the distribution of thermal noise power per unit bandwidth depends on the Boltzmann constant. To measure Doppler shift and range in radar, you have to specify a value for the speed of light. The following table summarizes the three physical constants used in the toolbox. Seephysconst
for additional information.
Constant | Description | Value |
---|---|---|
'LightSpeed' |
Speed of light in vacuum | 299,792,458 m/s. Most commonly denoted byc. |
'Boltzmann' |
波尔兹曼常数相关的母牛tic energy to temperature | J/K. 2006 NIST value, most commonly denoted byk. |
'EarthRadius' |
Mean radius of the Earth | 6,371,000 m |