Thread: dBm and Voltage
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Old June 8th 05, 04:57 AM
Korbin Dallas
 
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On Tue, 07 Jun 2005 01:54:14 -0700, Roy Lewallen wrote:

dBv = 1v
dBu = 1 uV
dBm = 1 mw
dBw = 1 w
dBk = 1 KW

Thanks, Tom. This newsgroup is truly educational. I'm slowly learning
that out there, somewhere, just about every possible convention or
nomenclature is used by someone for some purpose. I'll bet I'm the only
kid on my block now who knows what dBu and dBv mean. And I guess Len is
the only kid on his block that knows they sometimes mean dB relative to
1 uV, as well -- ah, what's a factor of 775,000 one way or the other,
anyhow.

dBu = dumb ******* unit.

Roy Lewallen, W7EL

K7ITM wrote:
This page: http://decibel.biography.ms/ mentions both dBv and dBu.
Says in "electrical voltage" (probably with reference to audio
industry), dBu and dBv both mean dB relative to 0.775V -- generally
0.775Vrms, but dB taken as 20 log(V/0.775), without reference to a
particular impedance.

But the same page says dBu or dB(lower-case Greek mu: "micro") as radio
power is dB relative to one microvolt per square meter.

Go figure. It all points out the need to be careful to define your
terms if there's any chance of ambiguity. If you're not careful, your
reader may think dBu refers to Dallas Baptist University, or Deutsche
Billiard Union, or Duluth Business University... though the
capitalization would be wrong for those.

Cheers,
Tom


--
Korbin Dallas
The name was changed to protect the guilty.