Review the General Troubleshooting recommendations before proceeding with this section.
This troubleshooting procedure assumes the PNA successfully passed the Power Level Accuracy (Source Power Accuracy) Performance Test. If this test fails to execute properly, make the there is sufficient power delivered to the counter input. The power level at the PNA output may be low or the cable may introduce significant power loss. Be sure to use the correct cable when connecting to the counter, and make sure the counter has warmed up before running the test.
A failure of the Frequency Accuracy Test is due to an inaccurate setting of the Oven-Controlled Crystal Oscillator (OCXO) on the Frequency Reference board assembly, or an inaccurate setting of the Permanent Magnet YIG Oscillator (PMYO) on the source assembly.
First, verify the accuracy of the 10 MHz OCXO output by connecting a frequency counter to the 10 MHz REF OUTPUT on the rear panel. The required test equipment is:
If the 10 MHz REF output is off by more than 10 Hz, adjust the output of the OCXO by performing the 10 MHz Frequency Adjustment. Next, perform the 3.8 GHz Frequency Adjustment.
If the measurement uncertainty is unexpectedly large, it is most probably caused by the accuracy specification for the time base used by the counter. If the counter uses in internal time base, the counter does not have the required option. If an external time base is used, the value for frequency accuracy on the 10MHz External Reference is the likely source of the problem. See the Frequency Reference Explanation in the Frequency Accuracy Performance Test for more information.