dbm()

Converts voltage to decibel referenced to a 1 milliwatt signal and returns a real number

Syntax
dbm(Value, Zref)

Name	Description	Range	Type	Required
Value	Voltage	(-∞, ∞)	integer, real, complex	yes
Zref	Reference impedance	(-∞, ∞)	integer, real, complex	yes

Examples

y = dbm(0, 50)
returns -3046.527
y = dbm(1+j*2, 25)
returns 20.0
y = dbm(-30, 1+j*1)
returns 53.522

See Also

db(), dbmtoa(), dbmtov(), dbmtow(), dbpolar(), dbwtow(), wtodbm()

Notes/Equations

This expression calculates the decibel measure of a voltage referenced to a 1 milliwatt signal.

The value in dBm is calculated as follows:

where tinyreal = 2.22507e-308 (see Predefined Simulator Variables and Constants Reserved Names)

Given a power Po in Watts, the power in dB is:

while the power in dBm is: