top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration Why to Join

Facebook Login
Site Registration

Difference between dBm and dB ?

+3 votes
Difference between dBm and dB ?
posted Apr 6, 2014 by Neeraj Mishra

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button
This one is very simple, allow me to share just the link

1 Answer

+2 votes

dBm and dB both are used to measure power level.
dBm is used to measure power with reference of 1 milliwatt. I mean to say power level is calculated using following formula:

dBm = 10 * log (P2/1milliwatt).

Whereas decibel is used for ratio of two power level using the following formula:
dB = 10 * log (P2/P1).

answer Apr 6, 2014 by Vimal Kumar Mishra
Some comments -
1. dB is used to quantify ratio between two intensity or power values while dBm is used to express an absolute value of power.
2. dB is a dimensionless unit while dBm is an absolute unit.
3. dB is relative often relative to the power of the input signal while dBm is always relative to 1 mW signal.
Similar Questions
+1 vote

Why dBm unit is used in case of doing measurement for RSRP and why dB is used for RSRQ ?
What reasoning is behind it ?

0 votes

I came to know 5G radio is going to use something called Filter OFDM unlike 4G radio which was using cyclic prefix OFDM.

+1 vote

I live in a remote location with awful reception, and a friend suggested I should get a signal booster. I can connect to LTE if I force it in my phone's Hidden Menu (LG G5) but it functions basically at the same speed as HSPA, however when I visit a big city the 4G connection kicks in on its own and at very high speeds.

I found out that my phone carrier is using Band 3 for LTE which should mean that I need a 1800 Mhz signal booster which I found on ebay, but I'd really appreciate it if someone who actually knows this stuff could take a look and say if I'm right in my choice of this signal booster.

Included are screenshots of my Phone's LTE connection details as well as the item page of the signal booster I found.

+1 vote

I know few name of reference signals such as Cell-Specific Reference Signal, MBSFN reference signals , UE specific reference signals and Positioning Reference Signals. But I want know where all these reference signals are transmitted and how it is determined ? And please add the reference signal name which I might have missed.

Contact Us
+91 9880187415
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Karnataka INDIA.