ATTRIBUTE-DESCRIPTION
            The measurement time is the time relative to the start of
            the overall sample.  It is computed from the measurement
            number, the waveform measurement frequency, and is refined
            further by the sweep channel, axis-number and trigger.
                      The first-order approximation of the measurement time is
            the measurement number divided by the product of 5 and the
            number of measurements per waveform (from the probe
            entity).  For probes sampled by the low-frequency board,
            the divisor is 160.  For probes sampled by the
            high-frequency board, the divisor is 10240.
                      The measurement time is achieved by adding to the
            first-order approximation the correction computed by
            dividing the sum of the sweep channel and the axis number
            by the trigger value.  For probes sampled by the
            low-frequency board, the maximum value of the correction
            is approximately 4.166 milliseconds.  For probes sampled
            by the high-frequency board, the maximum value of the
            correction is approximately 68 microseconds.  Because all
            the different axes and probes are not measured at exactly
            the same time, the correction is needed to accurately
            compute the phase of the axis relative to the other axes
            and probes.