Paradise Datacom HPAC-100-RM, Operation Manual

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5-2 Operations Manual: HPAC-100/125/150/200/250-RM SSPA
5 Performance Tests
Intermodulation Distortion
The third order intermodulation distortion products are caused by nonlinearities in the
system when more than one desired signal is present. Figure 5-1 depicts the two-
tone third order IMD products along with the desired signals.
Figure 5-1: Depiction of two tone third order IMD products.
Although 3f
1
and 3f
2
are also third order products, the two pictured products are
usually considered because they have the possibility of being in the frequency band
of interest. The products reduce the total output power of the amplifier and cause
interference with other signals and equipment. Because their existence is inevitable,
system applications require these unwanted signals be a specified level below the
desired tones. The levels of the IMD products vary with the output power of the
amplifier. As the unit approaches the 1 dB gain compression point, nonlinearities
are higher than when operating at lower power levels. Two tone tests are performed
on the RF module at different power levels and at different locations throughout the
operating frequency band.
RF Sample Port
Sample port data is measured at discrete frequencies across the band to character-
ize the internal couplers. The data for the input sample port is measured with re-
spect to the amplifier’s input while the data for the output sample port is measured
with respect to the amplifier’s output.
Front Panel Monitors and Controls
To verify that all front panel controls are functioning, the HPAC-100/125/150/200/250-
RM is operated in Local mode. All menu data and controls are verified along with the
setting of the user faults and thresholds. The contrast of the front panel LCD is set.
f
1
f
2
2f
2
-f
1
2f
1
-f
2
∆
f
∆
f
∆
f
IMD Product
IMD Product