Receiver Adjustment

This program adjusts the network analyzer receivers for a flat response across its full frequency range. This adjustment is for service only; not for measurement calibration.

NOTE: The is not available for E5080A and M9485A. An adjustment software is provided as an external software.

Required Equipment

See list of supported power meters and sensors.

See VNA Accessories

Notes

The power sensor depends on the VNA frequency range. Depending on the VNA model, two power sensors may be required to test the full frequency range. The VNA front panel connector type will determine the cable used and if an adapter is required with the power sensor(s).
In this adjustment, a power sensor with a specified lower frequency limit of 50 MHz may be used on all instrument that have a lower frequency limit of 10 MHz. Any added uncertainty is negligible.
If using an older style sensor (without built-in correction factors), refer to your power meter documentation to ensure the proper calibration factors for the power sensor have been entered into a table on the power meter.
You must be logged onto the VNA as an Administrator to perform an adjustment. Learn more.

Procedure

Click Utility, then System, then Service, then Adjustment Routines...
At the Adjustments selection, click Receiver Adjustment.
Connect a GPIB cable between the power meter and network analyzer.
Ensure the power sensor(s) are connected to the power meter.
The software presents you with two choices:

1. Click Inspect Flatness to observe flatness of receiver response versus frequency. Although there is no explicit specification for receiver flatness, Receiver Calibration should improve Transmission and Reflection Tracking error terms which are specified.
2. Click Calibrate to begin the receiver calibration process. The software prompts you to connect the sensor(s), cable and adapter as needed.

Additional Information

Receiver Adjustment tests all VNA receivers, taking approximately 15 and 45 minutes. Length is dependent on frequency range and number of ports.
Upon completion of the Receiver Adjustment, a transmission measurement of a good quality cable should appear to be smooth, with slightly increasing loss versus frequency. A reflection measurement of a short or open should appear to be a flat line across the entire frequency range with only a dB or two of variation/ripple. If instead, you see variations of 10-40dB, then the VNA may have a mixer problem. Typically, this means the uncorrected low end frequency phase relative to other receivers is different. This causes the correction algorithm to "blow up" and provide wildly incorrect data. This is almost always a hardware problem and typically one or more receivers must be replaced. The adjustment procedure has a quick test for this and it will show a warning message if excess phase shift is detected, however this test is not definitive and may not always catch every problem.

Troubleshooting

In the event there is a problem with Receiver Adjustment, please refer to the "Troubleshooting" chapter in your VNA Service Guide.

Data Storage

The correction data is stored in the flash memory on the Test Set Mother Board.