Teledyne 6 RU Chassis, Руководство по эксплуатации

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6 RU SSPA Chassis Operations Manual 202058 REV AA 79
4.2 Multi-Carrier Intermod Performance
The SSPA typically performs better under multicarrier environments than does a Trav-
eling Wave Tube Amplifier (TWTA). This is to say that the TWTA must waste a greater
percentage of its output power capability to achieve acceptable distortion levels. Tech-
niques such as pre-distortion linearization can improve the TWTA response to a
degree, but the SSPA is typically still superior.
Figure 4-3
shows a comparison of inter-
modulation distortion vs. back-off for an SSPA, TWTA, and linearized TWTA.
The SSPA can be operated at approximately one half (50 percent) of its total output
power capability to achieve -25 dB intermodulation distortion in multi-carrier environ-
ments. The TWTA can only be operated at 20 percent of its total output power capa-
bility to achieve the same intermod performance. The linearized TWTA can be operat-
ed at 33% of its capacity to achieve the same intermod performance. Clearly the SSPA
is a much more efficient amplification system under multi-carrier operating environ-
ments.
Figure 4-3: Two-Tone Intermod vs. Output Backoff