Is there an Omega sign available?

Discussion in 'Cadence' started by Svenn Are Bjerkem, Sep 7, 2005.

  1. Hi,

    to annotate my symbols I use

    strcat(cdsParam(1) " Ohm")

    for the illabel. Notice that it is a must to have that space, otherwise
    1 Ohm become 1Ohm which is 10 hectometer. Nonsense in respect to
    resistors, but how do you interpret
    r=1Ohm
    when looking quickly at it.

    This make the symbols a bit more readable, specially when milli is in
    play as 10m is more often read as 10 meters than 10 millisomething.
    Specially a problems with transmission lines that are 10mm. Imagine
    this: length=10m. So I decided to take the extra work to insert

    strcat(cdsParam(2) "m")

    to avoid stupid problems like this. Here the space is not needed as
    there will be no problem with misunderstanding. 10m m does not look as
    good as 10mm

    For resistance and conductance there are the greek symbol Omega used.
    (conductance on the head) Are these symbols available in any font used
    with cadence and how do I use them. I tried

    strcat(cdsParam(1) intToChar(234))

    as ascii 234 is supposed to be the Omega in the extended ascii according
    to www.lookuptables.com. Doesn't work as far as I can see, but no need
    to hunt for something if it doesn't exist in the first place.
     
    Svenn Are Bjerkem, Sep 7, 2005
    #1
  2. Svenn,

    I don't think anything outside the 7-bit ascii character set is available. Not
    really sure who in their right mind would interpret 1Ohm as 10 hectometers (does
    anyone actually use the unit hectometer anyway?).

    Not sure how appropriate making your labels something like
    strcat(cdsParam(1) " Ohm") is anyway. The point of cdsParam() is that the user
    can choose (via effective CDF, or edit->component display) what gets displayed
    in placeholder 1, 2, 3 etc. So what is to stop them replacing "r" with "tc"
    (say). Or annotating operating point informations (like current). Showing a
    current value (e.g 1uA) as "1u Ohm" will surely be rather confusing?

    Regards,

    Andrew.
     
    Andrew Beckett, Sep 7, 2005
    #2
  3. Nobody, it it just annoying. If the Omega sign is not available, then it
    is not available
    I think the unit of the property is as important as its magnitude. It
    would be nice if cdsParam() also fetched the unit type from CDF.

    Hardcoding things is always bad, but in this case the symbol in
    discussion is a top level symbol with parameters defined by me and
    there is no obvious need for the user to change what parameter is
    visible.
     
    Svenn Are Bjerkem, Sep 8, 2005
    #3
  4. In which case you might as well make it:

    strcat(instId~>paramName " Ohm")

    and miss out cdsParam(). That way there would never be any confusion!

    Regards,

    Andrew.
     
    Andrew Beckett, Sep 8, 2005
    #4
  5. Although the name of the person after whom the unit is named is Ohm, which
    is a proper noun and takes an initial capital, the SI unit is not a proper
    noun and is named ohm, with a lowercase 'o'. So, the confusion is less
    likely to arise: your example is 1ohm, which is not likely to be misread as
    ten hm.
     
    Matthew Kendall, Sep 13, 2005
    #5
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