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## pix - 12th September 2013  (19:30 GMT)

hi,

dB is not a "measurement" unit, it is a "comparison" unit. Your "dBm" measurement can be converted into mW, W or whatever power unit you want.

1dB does not mean anything by itself. You can only use "dB" to compare two values. For example: value A is 1dB higher than value B, whatever the values A and B.

If someone asks you to provide a measurement in "dB", it means they made a common mistake. They actually want "dBm".

Cheers
pix

## Dhananchezhiya Parasuram - 12th September 2013  (06:18 GMT)

I am using Selective Level Meter(SLM) to measure power line carrier communication gain in this meter its showing only the unit of dBm but I need to measure inform of dB Its there any formula to convert dBm to dB, any one can explain details please.

## lakhindar murmu - 21st August 2013  (10:55 GMT)

hi all
can anybody help me how to visualize group delay response of a microstrip filter in IE3D software?

## Somaliland - 15th May 2012  (08:56 GMT)

x = 10 log_{10}(1000P)
where P is the power in W and x is the power ratio in dBm

misa,

pix

## misa - 3rd May 2012  (12:27 GMT)

thanks pix for explanation , what is the mathematic formula to convert from DBm to Watt and vice versa

## pix - 15th April 2012  (07:30 GMT)

misa,

no, that is very very wrong.
dB cannot be converted in dBm ! those are not counting the same thing.

dBm is an absolute power. It can be converted in Watts.
2W = 33dBm

dB is a difference of dBm, and it has no physical existence other than this. It is a mathematical tool.

For example, from 39dBm to 42dBm, there is a difference of +3 dB.
You cannot convert 3dB to watts. But you can convert dBm into watts.
39dBm = 8W
42dBm = 16W

but 3dB is not equal to 8W !!!

Regards
pix

## misa - 10th April 2012  (19:53 GMT)

hi all

how can to convert from DB to DBm
is the formula that DBm=DB+30
and DB=DBm-30

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