Siglent Deskew Fixture (DF2001A)

To make accurate power loss measurements, you must perform current and voltage channel deskew using the DF2001A deskew fixture. The channel deskew procedure calibrates the time delay between current and voltage probes. This step is certainly important since a small delay in the timing of the voltage and current traces can cause a large error in the instantaneous power reading.

The deskew accuracy is a function of the electrical characteristics of the voltage and current probes as well as the rise time of the signal under test. In general, higher bandwidth probes will allow better rise time fidelity and better deskew resolution.

You need to perform the deskew procedure once initially, and you should re-run the procedure when any part of the hardware setup changes (for example, a different probe, different oscilloscope channel, etc.) or when the ambient temperature changes.

To perform the channel deskew, do the following steps:

1. First, demagnetize and zero-adjust the current probe.

2. Make connections to the DF2001A deskew fixture:

a. Connect D+ and D- of the high-voltage differential probe to the deskew fixture.

b. Connect the current probe to the loop with the direction of the arrow pointing towards the current flow.

c. Make sure the switch on the deskew fixture is set to the appropriate side of the fixture (either “small loop” or “large loop”).

d. Connect the deskew fixture to a USB port on your oscilloscope or a PC using a USB cable. The USB port supplies power to the deskew fixture.

3. Press the Utility on the front panel to enter the UTILITY function menu.

4. Press the Next Page softkey to enter the second page of the UTILITY function menu. 

Figure 101 Second Page of the UTILITY Function Menu

5. Press the Power Analyze softkey to enter the ANALYSIS function menu.

 Figure 102 UTILITY Function Menu

6. Press the Signal softkey to enter the SIGNAL setting menu. 

Figure 103 Power Analysis SIGNAL Menu

7. Press the Voltage softkey, and then turn the universal knob to select the analogy cannel probing the voltage signal.

8. Press the Current softkey, and then turn the universal knob to select the analogy channel probing the current signal.

9. Press the Deskew softkey to enter the DESKEW function menu.

Figure 104 DESKEW Menu 

10. Press the Auto Deskew softkey. When the process completes, you see a message indicating whether the deskew was successful, and if so, the settings being used. 

Figure 105 Deskew Success

General, you need to perform the deskew again when part of the test setup changes (for example, a different oscilloscope probe, different channel, etc.) or when the ambient temperature has changed.