per tick.
<P>
 
   When the function described by the pairs of time values and rates is
   continuous, then all rates except for the last one are redundant, since
<P>
 
<PRE>
                    parsys(i+1) -  parsys(i)
   rate(i)/MSF  =   ------------------------
                     sclk(i+1)  -   sclk(i)
</PRE>
   If the mapping from encoded SCLK to the parallel time system is not
   continuous, then the mapping will not be strictly invertible: if an
   encoded SCLK value is mapped to a parallel time val