Technical data
Service Guide 85309-90082 2-15
LO/IF Distribution Unit Operating Information
85309B Performing the Operator’s Check
LO Power Output Test
NOTE The PNA input must be attenuated to avoid causing receiver compression or damaging the
receiver. An external 30 dB pad attenuator is required if the PNA does not have an internal
source step attenuator. The instructions for this test use PNA Port 1 to generate the LO
source, and use PNA Port 2 as receiver B.
NOTE All keystrokes in the following procedure are for the PNA. Using an ENA may require
different keystrokes.
1. On the PNA, select Preset.
2. Unless already accomplished by the Preset selection, select Start Frequency and enter 0.1 GHz, then
select Stop Frequency and enter 18 GHz.
3. To activate the PNA receiver B, select Response > Meas > More > Receivers.
4. Set the Port 1 source power level to 0 dBm.
5. Zero and calibrate the power sensor.
6. Connect a test cable between PNA Port 1 and the power sensor.
7. To perform the source power calibration, select Cal > Power Cal > Source Cal.
8. Make the following selections in the Source Power Calibration menu:
a. Channel 1 = Port 1
b. Tolerance = 0.1 dBm
c. Maximum number of readings = 50
9. Follow the calibration wizard instructions on the PNA to complete the source power calibration. If
necessary, refer to the section titled “Power Calibration” in the embedded Help System of the PNA.
10. After completing the source power calibration, remove the power sensor from the Port 1 cable.
11. Make the following selections to set the PNA receiver attenuator
1
B to 30 dB:
a. Select Power > Power and Attenuator.
b. Select receiver attenuator B.
c. Enter a value of 30 dB.
12. Connect a test cable to Port 2.
13. Connect a thru adapter between Port 1 and Port 2.
14. Normalize the receiver B trace. If necessary, get instructions by searching the embedded Help System of
the PNA for “normalize.” After normalizing, the trace should be flat at 0 dBm.
15. Remove the thru adapter between the two test cables.
1. If the PNA receiver does not have an internal step attenuator, an external 30 dB pad attenuator
must be connected to Port 2.