APPENDIX 12
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Appendix 3 Reference
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Appendix 3.6 Averaging Equations
Appendix 3.7 "2-point method" Scaling Equation
For time axis averaging in memory recorder and FFT functions, summing
averaging is synchronized by the trigger.
If trigger synchronization is not performed, the results will be meaningless.
In FFT function, unlike time axis averaging, results are valid also if no
trigger synchronization is used. But if the characteristics of the input
waveform allow triggering, using the trigger for synchronization is
recommended.
Summing averaging (simple averaging in FFT)
Captured data are added sequentially and the sum is divided by the number
of samples.
An = { (n - 1)An - 1 + Zn } /n
n Averaging count
A
n
Result of n times averaging
Z
n
n-th measurement data
Exponential averaging
Most recent data are given greatest weighting, and the weighting of older
data is reduced with an exponential function.
An = { (N - 1)An - 1 + Zn } /N
N Specified averaging count
n Averaging count
A
n
Result of n times averaging
Z
n
n-th measurement data
Peak hold (frequency axis: FFT)
The specified number of samples are captured, and the peak value is held
(stored) for each frequency.
Y ={(SCH - SCL)/(VH - VL)} X + {(VH×SCL - VL×SCH )/(VH - VL)}
VH: Voltage high point SCH: Scaling high point
VL: Voltage low point SCL: Scaling low point
The ranges for the parts enclosed in dotted lines are as follows.
-9.9999E+9 ≦｛ ｝value of enclosed part ≦ -1.0000E-9
-9.9999E+9≦｛ ｝value of enclosed part ＝ 0
+1.0000E-9 ≦｛ ｝value of enclosed part ≦ +9.9999E+9
・When a setting outside of the above range is attempted, a warning indication
is given and the setting becomes "converted value" = "voltage value" (no
scaling).
・For channels in which waveform processing result data are recorded, only
the unit is valid (scaling is invalid).
・The scaling value is used for the gauge scale, upper and lower display limits,
and for A･B cursor readings.
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