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IM 701210-05E
2.4 Setting Waveform Acquisition Conditions and Display Conditions
Envelope Mode
In normal mode and averaging mode, the sample rate (the number of times data is
acquired per second in the acquisition memory) drops if T/div is increased. (See
Appendix 1 “Relationship between the Time Axis Setting, Sample Rate and Record
Length.”)
However, in the envelope mode, the maximum and minimum values are determined at
every time interval from the data sampled at the maximum sample rate of each input
module. The time interval used to determine the value is equal to twice the sample rate
of the normal mode. The maximum and minimum values are paired and stored in the
acquisition memory.
Envelope mode is useful when you want to avoid aliasing, since the sample rate is kept
high irrespective of the time axis setting. It is also useful when you want to detect
glitches (pulse signals which rise very fast) or display an envelope of a modulating
signal.
Envelope curve
Box Average Mode
The rolling average of the data sampled at the maximum sample rate of the 701250
(HS10M12) and 701255 (NONISO_10M12) is determined. The resultant data is stored
in the acquisition memory and used to generate the display. Box averaging is useful for
eliminating small amount of noise on the input signal. It can also remove noise from a
single-shot signal.
Time
Time
1
2
20
a
21
Input signal
(500 kS/s)
Box averaged data
b
. . . . .
.
36
. . . . .
. . .
Voltage
Voltage