1-13
1
IM 701830-01E
Functions
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 (refer to 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 module. The time interval used to
determine the values is equivalent to the sampling interval of the normal mode. The maximum
and minimum values are paired and acquired in the acquisition memory.
Envelope mode is useful when you want to avoid aliasing (page 1-3), since the sample rate is
kept high irrespective of the time axis setting (T/div). Furthermore, envelope mode is also
useful when you want to detect glitches (pulsing signals which rise very fast) or display an
envelope of a modulating signal.
Envelope
Box average
See below.
Sequential Store
≡
Page 7-4.
≡
Waveform data will be stored in the acquisition memory only a set number of times, and all
waveforms can be displayed. This stops automatically after acquisition. The maximum
acquisition count available with the feature varies according to the displayed record length.
Once the specified number of waveforms have been stored, you can display any of the
waveforms individually or all of them together, so that it is possible to derive a time series of
the waveform variation. The drawings below illustrate how stored data can be displayed
(assuming sequential storage of 100 waveforms).
Display example in case count=100 times
Displaying all waveforms
(ALL)
Displaying newest waveform
(Selected Record No.=0)
Displaying oldest waveform
(Selected Record No.=–99)
Box average
≡
Page 7-5.
≡
Taking the data sampled at 10 MS/s, the moving averages of certain number of data points are
determined as shown in the following figure. These data are acquired in the acquisition
memory and displayed. Box averaging is useful for eliminating the small amount of noise on
the input signal. It is also effective in removing the noise from a signal acquired only once.
Box averaging is only available on High-Speed Isolation/High-Speed Modules.
Voltage
Time axis
Time axis
1
2
16
20
a
21
Input signal
(at 500kS/s)
Box Averaging
data
b
• • • • •
36
• • • • •
• • •
Voltage
1.4 Setting the Acquisition and Display Conditions
