1 milli-watt = 10 dBm ? 1 dBm ?

[wwswimming]

i am writing about a project i worked on where the
goal was to develop maximum EMI isolation. the
rest of the team was working on a cell phone base
station.

it's embarassing not remembering this. i hope i
enjoyed losing those brain cells.

can somebody set me straight on this ?

thanks !

 

[ScottMac]

The "m" in dbm is for "milliwatt" (as in one milliwatt)

I think the line is something like "relative gain or loss, relative to 1 milliwatt"

So, a power output of 1 milliwatt would be 0dbm (zero db of gain/loss, relative to 1 milliwatt)

Good Luck

Scott

 

[wwswimming]

thanks !

i would hate to screw that up during an interview.

one job i worked on i built a fixture that had
143 dB of isolation over the band 100 MHz
to 2.5 GHz. that was a fun job. we worked
in big copper-plated rooms and everything.

 

[Fourier Transform]

Originally posted by: ScottMac
The "m" in dbm is for "milliwatt" (as in one milliwatt)

I think the line is something like "relative gain or loss, relative to 1 milliwatt"

So, a power output of 1 milliwatt would be 0dbm (zero db of gain/loss, relative to 1 milliwatt)

Good Luck

Scott

A bit late, but I second this. The "m" in dBm tells you that the power is referenced to 1mW.

As ScottMac stated, the power output of 1 mW would be 10*log(1mW/1mW) = 10*log(1) = 0 dBm

For 1 W, you'd have 10*log(1W/1mW) = 10*log(1000) = 30 dBm.