12
IM 701450-61E
Deskew Execution Example
In the example shown below, the waveform is displayed smoothly because the acquisition mode
(waveform acquisition condition) is set to averaging. When automatic deskew is executed, the
waveform is not smooth because the acquisition mode is set to normal.
Before skew correction
After skew correction
Voltage signal
Current signal
Explanation
To correctly measure the power analysis parameters such as power, impedance, power
factor, watt hour, and ampere hour from the voltage and current under analysis, the
difference in the transfer time of the voltage and current signals must be corrected
(deskewed).
Connecting the Deskew Correction Signal Source
Apply the voltage and current signals from the deskew correction signal source to the
pair of channels on the DL7400 that you wish to deskew using a voltage probe (passive
probe or differential probe) and a current probe. For a description on the pair of
channels for applying the voltage and current signals when measuring power analysis
parameters, see page 6 in this manual.
Note
For information on the handling of the deskew correction signal source, passive probe,
differential probe, and current probe, see the respective manuals.
Executing the Deskew
• Deskew is a function used to adjust the signal of the correction target channel (Target
CH) to match the signal of the channel set to be the trigger source* of edge trigger
along the time axis. It is a function used to correct the difference in the transfer time.
• Execute auto deskew after the warm-up time of the DL7400 and other equipment (as
necessary) has elapsed.
• As necessary, execute deskew on the channel pairs of CH1 and CH2, CH3 and CH4,
and CH5 and CH6.
*
For a description of the edge trigger and trigger source, see section 6.5 in the
DL7440/
DL7480 User’s Manual IM701450-01E
.
Auto Deskew
•
If you execute auto deskew, only the trigger source channel and the correction target channel
(Target CH) are displayed.
•
If you execute auto deskew, settings of T/div, ACQ menu, SIMPLE menu (TRIGGER menu),
CH menu, and MEASURE menu are changed to match the signal received from the 701935
Deskew Correction Signal Source. For details, see appendix 1.
Manual Deskew
•
You can deskew further after performing auto deskew described above.
•
For a description of the settings related to the vertical axis or horizontal axis (time axis) used
when displaying the signals applied to each channel, see the procedural explanations in the
respective sections in the
DL7440/DL7480 User’s Manual
shown below and set the display
for easy viewing of the correction condition.
•
Auto setup: section 4.5
• Channel ON/OFF: section 5.1
•
V/div setting: section 5.2
• Vertical position setting: section 5.3
•
Bandwidth limit selection: section 5.8
• T/div setting: section 5.12
4 Correcting (Deskewing) the Difference in the Transfer Time of Analyzed Signals
