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US4629996A
Expired / Lapsed
US
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Feed-forward microwave power amplifier with difference signal distortion cancellation circuit
Assignee: KDDI Corp
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Filing: 1984-11-15
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Granted: 1986-12-16
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Expires: 2004-11-15
Abstract
Abstract A feed forward microwave power amplifier having a divider for dividing an input signal into two parts, a first main amplifier for amplifying one of the divided signals, means for providing a part of the output of the first amplifier as a signal S 1 , means for providing a signal S 2 by another output of the divider, a subtractor for providing the difference between S 2 and S 1 , a second amplifier having the same gain as that of the first amplifier for amplifying this difference, a 3 dB coupler for coupling an output S 4 of the first amplifier and an output S 4 e, where e is a constant, of the second amplifier to provide coupled power which is free from distortion, and adjusting means for adjusting the level of signals S 1 and S 2 so that S 2 is higher than S 1 , and the value e is in the range between 0.2 and 0.5. The particular features of the present invention, compared with a prior feed forward amplifier, are the use of a 3 dB coupler, and the configuration of the second amplifier which accepts not only the distortion component but also some desired component of the output of the first amplifier.
Inventors
- 👤 Tatsuo Watanabe
- 👤 Kiyohiko Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:15
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3223; H03F1/3229
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
300 words
A feed-forward microwave power amplifier with difference signal distortion cancellation circuit, comprising: an input terminal; an output terminal; divider means in operable connection with said input terminal for dividing a signal input at said input terminal into a pair of divided signals with equal level S with each other; first amplifier means in operable connection with said divider means for amplifying one of said divided signals and providing an output signal having a level S 4 ; means in operable connection with said first amplifier means for providing a signal having a level S 1 which is a part of an output of said first amplifier means; means in operable connection with said divider means for providing a signal having a level S 2 from the other of said divided signals output from said divider means; subtraction means for providing a difference signal corresponding to the difference between levels S 2 and S 1 ; second amplifier means in operable connection with said subtraction means and having the same power capacity as that of said first amplifier means, for amplifying said difference signal and outputting a signal having a level of S 4 e, where e is a constant value during small signal operation; 3dB coupler means in operable connection with said first amplifier means and said second amplifier means for coupling said output signal having said level S 4 from said first amplifier means and said output signal having said level S 4 e from said second amplifier means and providing a coupled power output signal to said output terminal; and adjusting means for adjusting said level S 1 and said level S 2 so that said level S 2 is higher than said level S 1 and said value e is in the range between 0.2 and 0.5.
Claim 2
Dependent Claim
300 words
A feed-forward microwave power amplifier with difference signal distortion cancellation circuit, comprising: an input terminal; an output terminal; divider means in operable connection with said input terminal for dividing a signal input at said input terminal into a pair of divided signals with equal level S with each other; first amplifier means in operable connection with said divider means for amplifying one of said divided signals and providing an output signal having a level S 4 ; means in operable connection with said first amplifier means for providing a signal having a level S 1 which is a part of an output of said first amplifier means; means in operable connection with said divider means for providing a signal having a level S 2 from the other of said divided signals output from said divider means; subtraction means for providing a difference signal corresponding to the difference between levels S 2 and S 1 ; second amplifier means in operable connection with said subtraction means and having the same power capacity as that of said first amplifier means, for amplifying said difference signal and outputting a signal having a level of S 4 e, where e is a constant value during small signal operation; 3dB coupler means in operable connection with said first amplifier means and said second amplifier means for coupling said output signal having said level S 4 from said first amplifier means and said output signal having said level S 4 e from said second amplifier means and providing a coupled power output signal to said output terminal; and adjusting means for adjusting said level S 1 and said level S 2 so that said level S 2 is higher than said level S 1 and said value e is in the range between 0.2 and 0.5.
Claim 3
Dependent Claim
31 words
A microwave power amplifier according to claim 1, wherein a pre-distortion circuit is provided at an input of said first amplifier means for compensating for distortion in said first amplifier means.
Claim 4
Dependent Claim
57 words
A microwave power amplifier according to claim 1, wherein said adjusting means comprises a directional coupler and an attenuator for providing said signal having said level S 1 from an output of said first amplifier means, and an auxiliary amplifier means for providing said signal having said level S 2 from an output of said divider means.
Claim 5
Dependent Claim
37 words
A microwave power amplifier according to claim 1, wherein said adjusting means comprises a directional coupler and an attenuator provided at an output of said first amplifier means, and another attenuator coupled with said second amplifier means.
Claim 6
Dependent Claim
64 words
A microwave power amplifier according to claim 1, wherein a delay circuit including a phase shifter is provided in a signal path to an input port of said 3 dB coupler means so that a pair of signals at input ports of said 3 dB coupler are in an inphase condition for desired signals, and in an opposite phase condition for distortion signal components.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-15 | 1990-06-16 | 1990-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-15 | 1994-06-16 | 1994-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-15 | 1998-06-16 | 1998-12-16 | $7700.00 | Window Closed / Lapsed |