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ptc-45821151-Visitor
1-Visitor
May 9, 2012
Solved

Working with dB (decibels)

  • May 9, 2012
  • 3 replies
  • 17398 views

dB_in_mathcad15.png

entering av1 and av2 in dB makes no diference:

dB_in_mathcad15_again.png

Any tip to avoid pitfalls using dB?.

Best answer by ValeryOchkov

Axel Harris wrote:

How do you hide brackets sorrounding N1?

I use the prefix operator:

http://twt.mpei.ac.ru/ochkov/Mathcad_14/Chapter1/1_036_Prefix.png

3 replies

V
24-Ruby IV
ValeryOchkov24-Ruby IV
24-Ruby IV
May 9, 2012

0+0=0

but 0dB+0dB is not equal 0dB

See the picture please

dB.png

    P
    ptc-45821151-VisitorAuthor
    1-Visitor
    May 9, 2012

    math_hidebrackets.jpg

    I colorized for clarity.

    How do you hide brackets sorrounding N1?

    V
    24-Ruby IV
    ValeryOchkov24-Ruby IVAnswer
    24-Ruby IV
    May 9, 2012

    Axel Harris wrote:

    How do you hide brackets sorrounding N1?

    I use the prefix operator:

    http://twt.mpei.ac.ru/ochkov/Mathcad_14/Chapter1/1_036_Prefix.png

      R
      RichardJ19-Tanzanite
      19-Tanzanite
      May 9, 2012

      They are not wrong, although they are not necessarily correct either. There is not one way to add values expressed in dB, there are two. And the root of your problem is that you are not distinguishing a dB that represents power (e.g. dBm) and a dB that represents gain. They are not the same thing, and cannot be handled the same way.

        N
        nas0k1-Visitor
        1-Visitor
        May 10, 2012

        "Everything you ever wanted to know about decibels but were afarid to ask..."

        Here is a good reference on dB & dBm:

        http://www2.rohde-schwarz.com/file_5613/1MA98_4E.pdf

        R
        RickMason1-Visitor
        1-Visitor
        September 20, 2012

        BTW, the postix operator does not work in Prime 2.0 at all and does not seem planned any time in the very near future!

        E
        ELSID1-Visitor
        1-Visitor
        November 7, 2012

        Rick,

        This is one of the many reasons my company has not converted ... sheets using functions features that are not yet supported in Prime

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