Granted Patent B2

US 8,581,662 · App. 13/246,121 · Granted Nov 12, 2013

Abstract

Claims (130)

1. A system for amplifying an input signal comprising:

a main amplifier to amplify a delayed version of the input signal;

a peak amplifier to amplify the input signal upon the input signal reaching a threshold level and disable amplification upon the input signal falling below the threshold level; and

a voltage combiner to electromagnetically couple the output of the main amplifier and the peak amplifier, such that an impedance between nodes at a given end of the voltage combiner is about zero if the input signal is below the threshold level, and wherein an output of the peak amplifier is applied to another end of the voltage combiner and an output of the main amplifier is applied to a node at the given end of the voltage combiner.

2. The system of claim 1 , wherein the voltage combiner comprises a coaxial cable.

3. The system of claim 2 , wherein the voltage combiner comprises a quarter wave impedance inverter.

4. The system of claim 2 , wherein the output node of the peak amplifier is coupled to a center conductor of the coaxial cable at the another end of the coaxial cable, the another end being distal to the given end of the coaxial cable.

5. The system of claim 4 , wherein a shielding of the coaxial cable is coupled to an electrically neutral node at the another end of the coaxial cable.

6. The system of claim 5 , wherein an output node of the main amplifier is coupled to the shielding of the coaxial cable at the given end of the coaxial cable.

7. The system of claim 6 , wherein the center conductor at the another end of the coaxial cable comprises an output node of the voltage combiner.

8. The system of claim 1 , wherein the amplifying system provides a return loss for the main amplifier below about −20 dB for a bandwidth of at least about 315 MHz.

9. The system of claim 1 , wherein the amplifying system provides a high impedance at the output node of the peak amplifier if the input signal is below the threshold level.

10. The system of claim 2 , wherein the coaxial cable has a length of about one quarter wavelength of the input signal.

11. The system of claim 1 , wherein the voltage combiner provides quarter wave impedance inversion in the absence of a short at an output of the voltage combiner.

12. The system of claim 1 , wherein:

Z

peak

=

Z

o

·

(

δ

-

1

)

·

I

main

δ

·

I

main

-

I

main_max

for

⁢

⁢

I

main

≥

I

main_critical

wherein:

Z peak comprises an impedance observed in an output of the peak amplifier;

Z o comprises the amplifying system impedance;

I main comprises a current output by the main amplifier;

I main —criticail comprises a current output by the main amplifier when the input signal is at the threshold level;

I main —max comprises a maximum current output by the main amplifier; and

δ

=

I

main_max

I

main_critical

.

13. The system of claim 1 , wherein:

Z

main

=

{

δ

·

Z

o

for

⁢

⁢

I

main

<

I

main_critical

Z

o

·

[

δ

-

(

δ

-

1

)

·

δ

·

I

main

-

I

main_max

I

main

]

for

⁢

⁢

I

main

≥

I

main_critical

wherein:

Z main comprises an impedance observed at an output of the main amplifier;

Z o comprises the amplifying system impedance;

I main comprises a current output by the main amplifier;

I main —critical comprises a current output by the main amplifier when the input signal is at the threshold level;

I main —max comprises a maximum current output by the main amplifier; and

δ

=

I

main_max

I

main_critical

.

14. A system for amplifying an input signal comprising:

a main amplifier to amplify a delayed version of the input signal;

a peak amplifier to amplify the input signal upon the input signal reaching a threshold level and disable amplification upon the input signal falling below the threshold level; and

a coaxial cable to electromagnetically couple the output of the main amplifier and the peak amplifier, and wherein an output of the peak amplifier is applied to a given end of the coaxial cable and an output of the main amplifier is applied to another end of the coaxial cable.

15. The system of claim 14 , wherein the coaxial cable provides a quarter wave impedance inversion for the input signal.

16. The system of claim 15 , wherein the amplifying system provides a return loss for the main amplifier below about −20 dB for a bandwidth of at least about 315 MHz.

17. The system of claim 14 , wherein the peak amplifier comprises a nonlinear amplifier and the main amplifier comprises a linear amplifier.

18. A system for amplifying an input signal comprising:

a main amplifier to amplify a delayed version of the input signal;

a peak amplifier to amplify the input signal upon the input signal reaching about one quarter of a peak level of the input signal and disable amplification upon the input signal falling below about one quarter of the peak level; and

a voltage combiner to electromagnetically couple the output of the main amplifier and the peak amplifier, such that an impedance between nodes at a given end the voltage combiner is about zero if the input signal is below the threshold level, and wherein an output of the peak amplifier is applied to another end of the voltage combiner and an output of the main amplifier is applied to a node at the given end of the voltage combiner.

19. The system of claim 18 , wherein the voltage combiner comprises a coaxial cable.

20. The system of claim 19 , wherein the coaxial cable provides a quarter wave impedance inversion for the input signal.

Assignments (14)