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  1. OMG Issue

SPTP — The properties of timing devices

  • Key: SPTP-144
  • Legacy Issue Number: 5320
  • Status: closed  
  • Source: The MathWorks ( Mr. Alan Moore)
  • Summary:

    "• The properties of timing devices are listed, but some of them are not explained, and
    no clue is given as to measure or represent them. This is the case for stability and skew.
    In particular, the relationship between skew and offset should be explicit.
    • Last paragraph but one, last sentence, definition of drift: the definition does not appear
    very clear to me: what can be the relative frequency of a clock between two successive
    ticks? Is not the drift simply measured by (the absolute value of) the difference of fre-quencies?
    (Frequency taken with the usual definition, one over the period.)
    • Last paragraph, last sentence: It says that a timer is always associated with a particular
    clock; this is not explicit on the diagram of fig. 5-3; in fact, according to this diagram,
    a timer is indirectly and implicitly associated with (at least) two clocks, one coming
    through inheritance from TimingMechanism (the reference clock) and the other com-ing
    through the association with TimeValue, which is itself associated with a refer-ence
    clock; there is no constraint to express that these two clocks should be the same.
    Should they?"

  • Reported: SPTP 1.0b1 — Wed, 22 May 2002 04:00 GMT
  • Disposition: Resolved — SPTP 1.0
  • Disposition Summary:

    see above

  • Updated: Fri, 6 Mar 2015 20:59 GMT