Paradise RA 5785 User Manual download pdf (Page 49)

Operations Manual, HPA3, Mini Compact Outdoor SSPA 208143 REV - 49

5.1.5 Intermodulation Distortion

Intermodulation distortion is one of the most important characteristics of a Solid State power

amplifier system. Satellite communication systems must comply to certain distortion levels

depending on the service involved. All production amplifiers are subjected to automated

intermod testing. This is based on a standard two-tone intermod test in which the intermod

level (IMD) is measured in dBc with respect to the main tones and the highest third order

intermod products.

Satcom amplifiers are typically used in some ‘back-off’ condition. This is the operating point at

which the composite output power is ‘backed-off’ from the amplifier’s P

1dB

, compression point.

A curve of back-off vs. IMD level is especially useful in the selection of a power

amplifier or determining the proper output power setting in a Satcom system.

Paradise Datacom recognizes the importance of this back-off characteristic and provides a

plot of back-off vs. IMD from 1 dB to 10 dB back from the amplifier’s compression point.

Figure 5-2, Item [3], shows a typical back-off curve from a production test set.

5.1.6 Power Requirements

This test measures the power requirements of the unit over the various voltages appropriate

for the unit under test. See Figure 5-3, Item [1].

Figure 5-3: M&C, Output Power, Ground, Phase Lock and Misc. Data

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Paradise RA 5785 User Manual Page 49