Thread
:
dBm and Voltage
View Single Post
#
13
June 4th 05, 10:06 PM
Roy Lewallen
Posts: n/a
wrote:
A basic definition that is industry-wide, government-wide,
has "dbm" as decibels of "0 dbm" related to a power level of
1.0 milliWatts in a "50 Ohm system." That has become so
widespread that specification writers don't always include
those words. It is implicit when referring to RF components.
. . .
That's common in the RF industry, but many others also use dBm -- for
example, it's often used in video systems where the standard impedance
is 75 ohms, and others where the standard is 600 ohms. In all those
applications, dBm is universally defined and understood to mean dB
relative to 1 mW, regardless of the impedance.
Roy Lewallen, W7EL
Reply With Quote
