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Chapter 5
Measurement Definition
Measurement Parameter Definition
Measurement Parameter Definition
This section provides the parameter definitions for measurements. The TAA, PW, Baseline
and Resolution parameters can be measured by a parametric module or an oscilloscope.
There is a slight difference in measurement definition between the two.
TAA Measurement
The TAA is defined as the average peak-to-peak amplitude measurement for a period.
Oscilloscope
When an oscilloscope is used for TAA measurement, TAA is measured as the average
peak-to-peak amplitude for several waveform periods. The number of waveform periods is
specified by the “hpe5022_waveAverage” function.
TAA positive and TAA negative are the average amplitudes between the
real-time-measured baseline and peaks. The baseline definition is shown in Figure 5-4.
Parametric Module
When parametric module is used for TAA measurement, it is measured as the average
peak-to-peak amplitude for a number of disk revolutions. The number of revolutions for
averaging is specified by the ‘ave.’ parameter.
TAA positive (TAA+) is the average amplitude between the baseline reference specified by
the “hpe5022_baselineReference” function and the positive peaks. TAA negative (TAA-)
is measured between the baseline reference and the negative peaks.
TAA Asymmetry is defined as :
Equation 5-1
TAA Asymmetry Definition
Modulation defined as the modulation of amplitude during one revolution. TAA data of the
last revolution of TAA measurement is used to calculate. TAA
RawDataMax
is a maximum
amplitude level in the last revolution. TAA
RawDataMin
is a minimum one. TAA is an
averaged amplitude level in the last revolution.
Equation 5-2
Modulation Peak to Peak Definition
TAA
Asymmetry
TAA
positive
TAA
negative
Ð
TAA
positive
TAA
negative
+
---------------------------------------------------------------
=
Modulation
PeaktoPeak
TAA
RawDataMax
TAA
RawDataMin
Ð
TAA
------------------------------------------------------------------------------------
=
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