Start networking and exchanging professional insights

Register now or log in to join your professional community.

Follow

What is the difference between dB and dBm? Provide an example of usage.

Decibel (dB) and dB relative to a milliwatt (dBm)

user-image
Question added by Andriy Ilyashenko , Technical Design Lead , Actavo Group Limited
Date Posted: 2017/09/11
Waqar Ahmed
by Waqar Ahmed , ELV Technician , Umbrella Security

dB and dBm are both units of measurement used to express the power of a signal, but they are based on different reference points.

dB is admentional unit used to make a comparison between 2 levels of power, voltage or current  dB=10 log (Pa/Pb).

dBm is a unit of any level of power referred to 1mW, in another word:                       dBm = 10log (P(mW)/1 mW) 

Syed Zeeshan Badar
by Syed Zeeshan Badar , RF Ops Lead , Cybernet

It is used forquantifying the ratio between two values. The best example of this is the signal-to-noise ratio.

Musaed Alsayadi
by Musaed Alsayadi , Telecom engineer , MAN

0dB= 30dbm

dB is the unit of power in Watt

dBm is the unit of power in mWatt

SAKHAMURI AKHIL KUMAR
by SAKHAMURI AKHIL KUMAR , Project Coordinator , Jnet technologies Pvt Ltd

dB vs. dBm. Decibel (dB) and dB relative to a milliwatt (dBm) represent two different but related concepts.The unit dBm denotes an absolute power level measured in decibels and referenced to 1 milliwatt (mW).

Sibin Thomas
by Sibin Thomas , Network Security Engineer , Masafi Co LLC

Whenever tests are performed on fiber optic networks, the results are displayed on a meter readout in “dB.” Optical loss is measured in “dB” while optical power is measured in “dBm.” Loss is a negative number (like –3.2 dB) as are most power measurements.

devi mohan nagireddy
by devi mohan nagireddy , network engineer , Terasoft ltd Network operations

db and dbm r differnt but they r relative.db is the ratio of two values.dbm is the absolute power level in db's in milliwatt

Jehangir Iqbal
by Jehangir Iqbal , Senior Low Current Engineer , Omrania Engineers & Consultant

Decibel (dB) and dB relative to a milliwatt (dBm) represent two different but related concepts. A dB is a shorthand way to express the ratio of two values. ... The unit dBm denotes an absolute power level measured in decibels and referenced to 1 milliwatt (mW)

Ibral Majid
by Ibral Majid , Construction Manager , Aesthetics, Consultants & Contractors

Decibel (dB) and dB relative to a milliwatt (dBm)

Abdulwahid Ahmed Musaeed AL-Sayadi
by Abdulwahid Ahmed Musaeed AL-Sayadi , RF Planning & Optimization Engineer (2G/3G/4G) , Yemen Mobile Company

dBm value=(dB value+)

 

 

because dBm is reference to milli 

REHAN ANWAR
by REHAN ANWAR , Trainee , National Telecom Corporation

dB is a measurement unit to quote the signal strength of a strong signal where dBm is a smaller unit , usually used with the prefix milli 

More Questions Like This

Do you need help in adding the right keywords to your CV? Let our CV writing experts help you.