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PXIe-5665 Calibration Procedure
15. Wait 2.5 s before making the first measurement and wait 100 ms before making subsequent
measurements to allow the PXIe-5665, RF source 1, and RF source 2 amplitudes to settle.
Note
Settling times are a characteristic of the RF source device. Refer to the
section of this document for a list of NI-recommended source devices and
device specifications. If you use an RF source device with different device
specifications, your settling times may differ from those listed in this procedure.
16. Measure the power spectrum with the PXIe-5665.
17. Find the highest peak within the measurement bandwidth. This value is the
IMD Low
Power
.
18. Repeat steps 11 to 16 for the PXIe-5665 center frequencies of
P1 Frequency
,
P2 Frequency
, and
IMD High Frequency
. The values from step 16 are
IMD Low Power
,
P1
Power
,
P2 Power
, and
IMD High Power,
respectively.
19. Calculate the upper and lower third-order intercept (TOI) points using the following
equations:
TOI Upper = P1 Power + (P2 Power - IMD High Power)/
2
TOI Lower = P2 Power + (P1 Power - IMD Low Power)/
2
20. The smaller of the
TOI Lower
and
TOI Upper
values is the
TOI Minimum
.
21. Repeat steps 8 to 19 for all test frequencies in Table 29.
22. Repeat steps 5 to 20 with the PXIe-5665 preamplifier enabled.
23. Compare the
TOI Minimum
to the verification test limits in Table 30 or Table 31 as
appropriate.
Table 30.
TOI (Frequencies
≤
700 MHz) Verification Test Limits (Preamplifier Disabled)
Center Frequency
As-Found Limit (dBm)
As-Left Limit (dBm)
*
10 MHz to <100 MHz
+16
+17
100 MHz to 700 MHz
+19
+20
*
section of this document for more information
about as-left limits.
Table 31.
TOI (Frequencies
≤
700 MHz) Verification Test Limits (Preamplifier Enabled)
Center Frequency
As-Found Limit (dBm)
As-Left Limit (dBm)
*
10 MHz to <100 MHz
-3
-2
100 MHz to 700 MHz
+2
+3
*
section of this document for more information
about as-left limits.