User`s guide

2 Operation and Features

Math Operations

66 U3606B User’s Guide

dBm measurements

The logarithmic dBm (decibels relative to 1 mW) scale is

often used in RF signal measurements. The U3606B takes a

measurement and calculates the power delivered to a

reference resistance (typically 50 Ω, 75 Ω, or 600 Ω). Voltage

measurement is then converted to dBm.

The dBm function is logarithmic, and is based on a

calculation of power delivered to a reference resistance,

relative to 1 mW. The formula used for calculating dBm

measurements is:

You can select the reference resistance value through the

Utility menu. The default setting is 600 Ω.

NOTE

This math operation applies to voltage measurements only.

dBm 10 log

reading

reference resis cetan()⁄ 1 mW()⁄()×=

Enable the dBm function

To disable the dBm function

U3606-90054_UG_EN.book Page 66 Friday, July 11, 2014 5:12 PM