Why does my N4010A sometimes fail EDR Relative Power on a good DUT?

This may happen if the firmware is A.05.03.10 (or newer).

The root cause is that the N4010A RF Assembly introduces a pre-amp when the input range falls to -15dBm or less. The pre-amp takes a finite time to start working, which makes it possible for the first measurement to occur on the rising edge of the signal. If this happens then it skews the EDR Relative Power measurement, and may cause a good DUT to fail. The simple workaround is to stay above the N4010A input range threshold of -15dBm.

The default N4010A input range setting at the start of this test is +10dBm. Each time the DUT is instructed to take a step-down in power, the N4010A input range is reduced by 4dB. If we assume the DUT requires 10 steps to reach the minimum power level, then the N4010A input range is reduced to -30dB by the end of the test. The following command can be used to change the N4010A input range step-size from 4dB to 2dB:

DIAG:LINK:RANGe:DUTStep 2

This command must be sent before starting the EDR Relative Power test. The net effect is that the N4010A input range starts at +10dBm, and is only reduced as far as -10dBm. DUT output at minimum power will be approximately -35dBm, but this is not an issue for the N4010A; the -10dBm input range extends to below -55dBm.

Note: This command is not available in firmware releases that pre-date A.05.03.10.