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siunitx: typeset dBm

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Leo

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May 2, 2009, 9:31:32 AM5/2/09
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Hi there,

I use \si{\deci\bel\milli} for dBm, a unit for optical power.

But since \milli is a prefix, I wonder if it is correct to omit the
base?

Thank you.

--
.: Leo :. [ sdl.web AT gmail.com ] .: I use Emacs :.

Philipp Stephani

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May 2, 2009, 9:43:35 AM5/2/09
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Leo schrieb:

> I use \si{\deci\bel\milli} for dBm, a unit for optical power.
>
> But since \milli is a prefix, I wonder if it is correct to omit the
> base?

It might be better to define a new unit:

\newunit{\dBm}{dBm}

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Replace “READ-MY-SIG” by “tcalveu” to answer by mail.

Leo

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May 2, 2009, 9:50:34 AM5/2/09
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On 2009-05-02 14:43 +0100, Philipp Stephani wrote:
> Leo schrieb:
>> I use \si{\deci\bel\milli} for dBm, a unit for optical power.
>>
>> But since \milli is a prefix, I wonder if it is correct to omit the
>> base?
>
> It might be better to define a new unit:
>
> \newunit{\dBm}{dBm}

Thank you.

Joseph Wright

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May 2, 2009, 1:55:15 PM5/2/09
to
Leo wrote:
> Hi there,
>
> I use \si{\deci\bel\milli} for dBm, a unit for optical power.
>
> But since \milli is a prefix, I wonder if it is correct to omit the
> base?
>
> Thank you.
>

Must be wrong. Units in the SI are pretty definite about this. You are
trying to use two prefixes: "deci" and "milli". You can't have
"millitdecibels": you can have millibels or microbels.
--
Joseph Wright

Leo

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May 2, 2009, 2:00:24 PM5/2/09
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On 2009-05-02 18:55 +0100, Joseph Wright wrote:
> Must be wrong. Units in the SI are pretty definite about this. You are
> trying to use two prefixes: "deci" and "milli". You can't have
> "millitdecibels": you can have millibels or microbels.

http://en.wikipedia.org/wiki/DBm

I have nenver seen it written as dBmW except in that wikipedia page.

dBm is well established. Many instruments use them.

It looks like defining a new unit is the way to go. What do you think?

Joseph Wright

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May 2, 2009, 2:08:19 PM5/2/09
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Leo wrote:
> On 2009-05-02 18:55 +0100, Joseph Wright wrote:
>> Must be wrong. Units in the SI are pretty definite about this. You are
>> trying to use two prefixes: "deci" and "milli". You can't have
>> "millitdecibels": you can have millibels or microbels.
>
> http://en.wikipedia.org/wiki/DBm
>
> I have nenver seen it written as dBmW except in that wikipedia page.
>
> dBm is well established. Many instruments use them.
>
> It looks like defining a new unit is the way to go. What do you think?

In general, I recommend *not* using the unit interpreting system for
non-standard units as all sorts can go wrong. So yes, in this case I'd
probably do:

\newunit{\dBm}{dBm}

(I tend to avoid \SI{<number>}{<literal>} myself).
--
Joseph Wright

Leo

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May 2, 2009, 3:44:25 PM5/2/09
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On 2009-05-02 19:08 +0100, Joseph Wright wrote:
> In general, I recommend *not* using the unit interpreting system for
> non-standard units as all sorts can go wrong. So yes, in this case I'd
> probably do:
>
> \newunit{\dBm}{dBm}
>
> (I tend to avoid \SI{<number>}{<literal>} myself).

Thank you.

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