From: Holger Schurig <holgerschurig@gmail.com>
To: Emmanuel Grumbach <egrumbach@gmail.com>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: Re: wireless-regdb: Add A band in IL - And general point regarding tx power limits in the dbase
Date: Tue, 22 Jun 2010 10:52:34 +0200 [thread overview]
Message-ID: <201006221052.34484.holgerschurig@gmail.com> (raw)
In-Reply-To: <AANLkTinGczUb2xTX5RUtnrRnc2BitOjZnpkDeHPV9Hwf@mail.gmail.com>
> Can you please help me translation from mW to db ?
You cannot.
"dB" is without a reference. Is only a relative measurement. You can, however,
convert "dB" into some factor.
What we were talking about was "dBm". Here we use a reference point of one
milliwatt. Now you can convert dBm to milliwatt.
Another example of a "made absolute by using a reference" logarithmic scale is
the gain of antennas. It's usually described in dBi or dBd. The first takes
the (hypothetical) isotropical antenna, the second an dipol as reference.
For more info, search for "dBm" in http://en.wikipedia.org/wiki/Decibel
--
DH3HS, http://www.holgerschurig.de
next prev parent reply other threads:[~2010-06-22 8:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-26 6:49 [RFC] wireless-regdb: Add A band in IL Emmanuel Grumbach
2010-05-26 16:51 ` Luis R. Rodriguez
2010-05-26 17:32 ` Grumbach, Emmanuel
2010-05-26 17:46 ` Luis R. Rodriguez
2010-05-26 17:51 ` Grumbach, Emmanuel
2010-05-26 18:22 ` Luis R. Rodriguez
2010-06-02 19:46 ` Emmanuel Grumbach
2010-06-02 20:29 ` ] " Michael Green
2010-06-02 21:37 ` [RFC] " Luis R. Rodriguez
2010-06-18 18:42 ` John W. Linville
2010-06-20 5:41 ` Emmanuel Grumbach
2010-06-21 14:51 ` wireless-regdb: Add A band in IL - And general point regarding tx power limits in the dbase Michael Green
2010-06-21 14:57 ` John W. Linville
2010-06-21 17:12 ` Emmanuel Grumbach
2010-06-21 17:41 ` Michael Green
2010-06-22 8:52 ` Holger Schurig [this message]
2010-06-21 19:15 ` Johannes Berg
2010-06-21 19:40 ` Luis R. Rodriguez
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