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Linearized traveling wave tube circuit with pre-distortion linearizer

Imported: 24 Feb '17 | Published: 24 Aug '04

George F. Kirkman

USPTO - Utility Patents

Abstract

A traveling wave tube assembly has a traveling wave tube and a predistortion network RF coupled and physically coupled to the traveling wave tube. The traveling wave tube and the predistortion network may be located in a high temperature zone. An amplifier located in a low temperature zone, is coupled to the predistortion network by an RF connecting cable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a prior art traveling wave tube amplifier circuit.

FIG. 2 is a schematic view of a traveling wave tube amplifier circuit according to the present invention.

FIG. 3 is a schematic view of a predistortion network of FIG. 2

FIG. 4 is a output power versus input power of the circuit of FIG.

3.

FIG. 5 is a plot of the circuit of FIG. 3 used in FIG. 2 illustrating output power versus input power.

FIG. 6 is transfer characteristic for a traveling wave tube showing output power versus input power.

FIG. 7 is an output versus input power plot of a linearized traveling wave tube using the circuit of FIG.

3 and the transfer characteristics of FIG.

6.

FIG. 8A is a plot of C/3IM or NPR plot versus output backoff that illustrates the linearized traveling wave tube characteristic of the circuit of FIG.

7.

FIG. 8B is a plot of NPR versus output backoff of the circuit plotted in FIG.

7.

FIG. 9 is a schematic view of an alternative predistortion network according to the present invention.

FIG. 10 is an output power versus input power transfer characteristic of the circuit of FIG.

9.

FIG. 11 is a transfer characteristic plot showing output power versus input power using the predistortion network of FIG. 9 with a traveling wave tube having the characteristics of FIG.

6.

FIG. 12A is a plot of C/3IM performance of the traveling wave tube circuit of FIG.

11.

FIG. 12B is a plot of NPR versus output backoff showing the NPR performance of the linearized traveling wave tube circuit of FIG.

11.

Claims

1. A traveling wave tube circuit assembly comprising a traveling wave tube:

2. An assembler as recited in claim 1, wherein said amplifier is disposed in a low temperature zone.

3. An assembly as recited in claim 1, wherein said predistortion network comprises a limiter.

4. An assemble as recited in claim 1, wherein said predistortion network comprises:

5. An assembly as recited in claim 4, wherein said predistortion network further comprises a second attenuator coupled in said series with said phase shifter.

6. An assembly as recited in claim 4, wherein said predistortion network further comprises a transmission line coupled parallel to said limiter, said first attenuator and said phase shifter.

7. An assembly as recited in claim 6, wherein said transmission line has a third attenuator.

8. An assembly as recited in claim 7, wherein said predistortion network further comprises a second limiter coupled in series with said third attenuator.

9. An assembly as recited in claim 1, further comprising a second amplifier coupled in series with said first amplifier.

10. A traveling wave tube circuit assembly comprising:

11. An assembly as recited in claim 10, wherein said predistortion network comprises:

12. An assembly as recited in claim 10, wherein said predistortion network further comprises a second attenuator coupled in said series with said phase shifter.

13. An assembly as recited in claim 10, wherein said predistortion network further comprises a transmission line coupled parallel to said limiter, said first attenuator and said phase shifter.

14. An assembly as recited in claim 10, wherein said transmission line has a third attenuator.

15. An assembly as recited in claim 10, wherein said predistortion network further comprises a second limiter coupled in series with said third attenuator.

16. An assembly as recited in claim 10 further comprising a second RF amplifier coupled in series with said first RF amplifier.

17. A satellite comprising: