US4291277A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive predistortion technique for linearizing a power amplifier for digital data systems
Assignee: Harris Corp
•
Filing: 1979-05-16
•
Granted: 1981-09-22
•
Expires: 1999-05-16
Abstract
Abstract Distortion introduced into a multiamplitude signal format by a high power microwave amplifier is compensated by a system which adapts itself to non-linearities present in the amplifier and predistorts the input signals before they are subjected to the non-linearities created by the amplifier. The degree of predistortion is non-fixed and varies or is updated as the non-linear conversion characteristics of the amplifier change with time.
Inventors
- 👤 Robert C. Davis
- 👤 Robert W. Boyd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:40
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3247; H03C; H03C3/00; H03C3/02; H03C3/08; H03D; H03D7/00; H03D7/16; H03D7/165; H03D7/166; H03D7/168; H03F1/3294; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/36; H04L27/366; H04L27/367; H04L27/368; H03F2201/00; H03F2201/32; H03F2201/3233
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
154 words
In a communication system wherein signals to be transmitted are coupled through a modulation distorting amplifier that subjects the signals to shifts in signal characteristics away from their intended values, an arrangement for compensating for the distorting action of said amplifier comprising: first means, coupled to receive input signals representative of data to be transmitted, for generating first output signals representative of the intended output of said amplifier in the absence of its distortion action; second means, coupled to receive said input signals, for storing predistored modulation signals to be coupled through said amplifier in response to said input signals, said predistortion signals having characteristics such that the distortion action of said amplifier is compensated thereby; and third menas, coupled to said first and second means and to the output of said amplifier, for modifying predistorted modulation signals stored in said second means, in response to changes in the distortion action of said amplifier.
Claim 2
Dependent Claim
154 words
In a communication system wherein signals to be transmitted are coupled through a modulation distorting amplifier that subjects the signals to shifts in signal characteristics away from their intended values, an arrangement for compensating for the distorting action of said amplifier comprising: first means, coupled to receive input signals representative of data to be transmitted, for generating first output signals representative of the intended output of said amplifier in the absence of its distortion action; second means, coupled to receive said input signals, for storing predistored modulation signals to be coupled through said amplifier in response to said input signals, said predistortion signals having characteristics such that the distortion action of said amplifier is compensated thereby; and third menas, coupled to said first and second means and to the output of said amplifier, for modifying predistorted modulation signals stored in said second means, in response to changes in the distortion action of said amplifier.
Claim 3
Dependent Claim
71 words
An arrangement according to claim 1, wherein said third means comprises means, coupled to said first means and to the output of said amplifier, for comparing the output of said amplifier with first output signals generated by said first means, and for causing the predistortion modulation signals stored in said second means to be changed in response to a difference between the output of said amplifier and said first output signals.
Claim 4
Dependent Claim
60 words
An arrangement according to claim 2, wherein said third means further includes means, coupled to the output of said second means and said comparing means, for modifying the values of predistortion signals stored in said second means and read out therefrom, in accordance with the value of the difference between the output of said amplifier and said first output signals.
Claim 5
Dependent Claim
69 words
An arrangement according to claim 1, wherein said input signals comprise digital codes representative of multiamplitude modulation signals to be coupled through said amplifier, and said first means comprises means, responsive to a digital code applied thereto, for generating a pair of output digital codes respectively representative of the intended in-phase and quadrature values that define a symbol to be produced as the output of said amplifier for transmission.
Claim 6
Dependent Claim
69 words
An arrangement according to claim 3, wherein said input signals comprise digital codes representative of multiamplitude modulation signals to be coupled through said amplifier, and said first means comprises means, responsive to a digital code applied thereto, for generating a pair of output digital codes respectively representative of the intended in-phase and quadrature values that define a symbol to be produced as the output of said amplifier for transmission.
Claim 7
Dependent Claim
46 words
An arrangement according to claim 5, wherein said second means comprises a memory in which digitally encoded pairs of in-phase and quadrature predistortion signal values are stored and read out therefrom in response to receipt thereby of said digital codes applied thereto as said input signals.
Claim 8
Dependent Claim
30 words
An arrangement according to claim 6, wherein the digitally encoded pairs of in-phase and quadrature symbols read out from said memory are applied as respective inputs to said modifying means.
Claim 9
Dependent Claim
43 words
An arrangement according to claim 6, further comprising means for converting the digitally-encoded pairs of in-phase and quadrature signals read out from said memory into analog symbols and for up-converting and combining said analog signals into composite signals for transmission at microwave frequencies.
Claim 10
Dependent Claim
53 words
An arrangement according to claim 7, wherein said modifying means includes means for adding to said digitally-encoded pairs of in-phase and quadrature signals further digital code signals corresponding to respective values of the in-phase and quadrature components of said difference between the output of said amplifier and said pair of output digital codes.
Claim 11
Dependent Claim
43 words
An arrangement according to claim 9, further comprising means for converting the digitally-encoded pairs of in-phase and quadrature signals read out from said memory into analog signals and for up-converting and combining said analog signals into composite signals for transmission at microwave frequencies.
Claim 12
Dependent Claim
61 words
An arrangement according to claim 6, wherein said second means comprises an input storage means, a prescribed number of said digital codes in length, for receiving said digital codes and causing said digitally encoded pairs of in-phase and quadrature predistortion signals to be read out from said memory in accordance with the digital code value contained in said input storage means.
Claim 13
Dependent Claim
30 words
An arrangement according to claim 11, wherein the digitally encoded pairs of in-phase and quadrature signals read out from said memory are applied as respective inputs to said modifying means.
Claim 14
Dependent Claim
53 words
An arrangement according to claim 12, wherein said modifying means includes means for adding to said digitally-encoded pairs of in-phase and quadrature signals further digital code signals corresponding to respective values of the in-phase and quadrature components of said difference between the output of said amplifier and said pair of output digital codes.
Claim 15
Dependent Claim
43 words
An arrangement according to claim 7, further comprising means for converting the digitally-encoded pairs of in-phase and quadrature signals read out from said memory into analog signals and for up-converting and combining said analog signals into composite signals for transmission at microwave frequencies.
Claim 16
Dependent Claim
53 words
An arrangement according to claim 14, wherein said modifying means includes means for adding to said digitally-encoded pairs of in-phase and quadrature signals further digital code signals corresponding to respective values of the in-phase and quadrature components of said difference between the output of said amplifier and said pair of output digital codes.
Claim 17
Dependent Claim
40 words
An arrangement according to claim 15, wherein said third means comprises means, coupled to the output of said amplifier, for down-converting the output of said amplifier to lower frequency in-phase and quadrature components to be applied to said comparing means.
Claim 18
Dependent Claim
61 words
An arrangement according to claim 16, wherein said second means comprises an input storage means, a prescribed number of said digital codes in length, for receiving said digital codes and causing said digitally encoded pairs of in-phase and quadrature predistortion signals to be read out from said memory in accordance with the digital code values contained in said input storage means.
References Cited (Backward Citations)
GB1246209A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |