Patent US4652498A successfully refreshed from Google Patents.
Patent US6108385A successfully refreshed from Google Patents.
US6108385A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for reducing intermodulation distortion in digital wideband transmission systems
Assignee: Rateze Remote Mgmt LLC
•
Filing: 1996-07-08
•
Granted: 2000-08-22
•
Expires: 2016-07-08
Abstract
Abstract Signal processing to remove unwanted signal components of non-linear elements such as RF amplifiers in broadband wireless communications systems that exhibit unwanted intermodulation products. An information signal is processed to form a processed output signal, V od . A signal preprocessor includes a base modulator for modulating the information signal to form base modulated signals, a band modulator for modulating the base modulated signals to form an input signal, V i , a distortion processor for providing a predistortion signal V pd having selected predistortion terms of the Taylor series form [k 1 ,(V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ], and a broadband processor for combining the input signal V i and the predistortion signal V pd to form a predistorted signal V id with the selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] having reduced amplitude. A non-linear element having a non-linear transfer function for processes the predistorted signal V id to form the output signal with the selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] having reduced amplitude. Amplifiers achieve substantial improvements in efficiency, an increase of 40-80% of usable power, due to the reduction of intermodulation products. In particular, the third order products are reduced.
Inventors
- 👤 William Spencer Worley, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:05
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/36; H04L27/366; H04L27/367; H04L27/368; H03F1/3241
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
227 words
In a communications system including, a modulator for modulating a plurality of information signals to provide a broadband input signal, V i , having a plurality of frequency terms, a broadband processor for combining said input signal V i and a predistortion signal V pd to form a predistorted input signal V id , a non-linear element having a non-linear transfer function for processing the predistortion signal, V id , to provide an output signal, V o , where the output signal includes terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ], a predistortion processor comprising, term generator means for generating selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ], phase shifter means for providing phase shifts to the selected predistortion terms to provide phase shifted terms that will reduce corresponding ones of the said terms in the output signal, V o , periodic signal generator means for generating periodic signals from said phase shifted terms, scaling means for scaling the periodic signals in proportion to the transfer function of the non-linear element to form said predistortion signal V pd .
Claim 2
Dependent Claim
227 words
In a communications system including, a modulator for modulating a plurality of information signals to provide a broadband input signal, V i , having a plurality of frequency terms, a broadband processor for combining said input signal V i and a predistortion signal V pd to form a predistorted input signal V id , a non-linear element having a non-linear transfer function for processing the predistortion signal, V id , to provide an output signal, V o , where the output signal includes terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ], a predistortion processor comprising, term generator means for generating selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ], phase shifter means for providing phase shifts to the selected predistortion terms to provide phase shifted terms that will reduce corresponding ones of the said terms in the output signal, V o , periodic signal generator means for generating periodic signals from said phase shifted terms, scaling means for scaling the periodic signals in proportion to the transfer function of the non-linear element to form said predistortion signal V pd .
Claim 3
Dependent Claim
16 words
The predistortion processor of claim 1 wherein said periodic signal generator means is a cosine generator.
Claim 4
Dependent Claim
15 words
The predistortion processor of claim 1 wherein said term generator means generates third harmonic terms.
Claim 5
Dependent Claim
208 words
In the communication system of claim 1 wherein said modulator receives said input information signals as one or more information signals V 1 (t), V 2 (t), . . . , V j (t), . . . , V J (t) where J is an integer, receives one or more carriers ω 1 (t), ω 2 (t), . . . , ω J (t), . . . , ω J (t) and receives one or more scalers scalers a 1 , a 2 , . . . , a j , . . . , a J and wherein said modulator includes, base modulator means for baseband modulation of said information signals to provide one or more baseband signals m 1 (t), m 2 (t), . . . , m j (t), . . . , m J (t), band modulation means for modulation of the carriers by the baseband signals to form said input signals V i including one or more of the signals V i (1), . . . , V i (j), . . . , V.sub.(i)(J), and wherein said predistortion signal includes V pd (1), . . . , V pd (s), . . . , V pd )(S), where S is an integer.
Claim 6
Dependent Claim
37 words
The predistortion processor of claim 4 wherein said carriers ω 1 (t), ω 2 (t), . . . , ω j (t), . . . , ω J (t) are GSM carriers for a cellular communications system.
Claim 7
Dependent Claim
54 words
The predistortion processor of claim 1 wherein said term generator means generates said selected predistortion terms as third harmonic terms, H s (j), using J carriers ω 1 (t) ω 2 (t), . . . , ω j (t), . . . , ω J (t), where J is some integer, as follows: ##EQU12##
Claim 8
Dependent Claim
26 words
The predistortion processor of claim 6 wherein J is equal to 2 and said term generator means generates said third harmonic terms of the following forms:
Claim 9
Dependent Claim
17 words
The predistortion processor of claim 1 wherein said term generator means generates third and fifth harmonic terms.
Claim 10
Dependent Claim
19 words
The signal processor of claim 1 wherein said broadband processor includes a frequency division multiplexer and a digital-to-analog converter.
Claim 11
Dependent Claim
14 words
The signal processor of claim 1 wherein said non-linear element is an RF amplifier.
Claim 12
Dependent Claim
243 words
A signal processor method for processing an information signal to form a processed output signal comprising: modulating the information signal to form base modulated signals, modulating the base modulated signals to form an input signal V i , providing a predistortion signal, V pd , using the steps of, generating selected distortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] where k 1 , k 2 , k 3 , . . . are amplitudes of the terms (V i ) 1 , (V i ) 2 , (V i ) 3 , . . . , respectively, phase shifting said selected distortion terms to provide phase shifted terms, generating periodic signals from the phase shifted terms, scaling the periodic signals in proportion to a non-linear transfer function to form said predistortion signal, V pd , combining said input signal, V i , and said predistortion signal, V pd , by broadband processing to form a predistorted signal, V id , with said selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] reduced in amplitude, processing said predistorted signal V id in a non-linear element having said non-linear transfer function to form said processed output signal.
Claim 13
Dependent Claim
243 words
A signal processor method for processing an information signal to form a processed output signal comprising: modulating the information signal to form base modulated signals, modulating the base modulated signals to form an input signal V i , providing a predistortion signal, V pd , using the steps of, generating selected distortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] where k 1 , k 2 , k 3 , . . . are amplitudes of the terms (V i ) 1 , (V i ) 2 , (V i ) 3 , . . . , respectively, phase shifting said selected distortion terms to provide phase shifted terms, generating periodic signals from the phase shifted terms, scaling the periodic signals in proportion to a non-linear transfer function to form said predistortion signal, V pd , combining said input signal, V i , and said predistortion signal, V pd , by broadband processing to form a predistorted signal, V id , with said selected predistortion terms of the Taylor series form [k 1 (V i ) 1 , k 2 (V i ) 2 , k 3 (V i ) 3 , . . . ] reduced in amplitude, processing said predistorted signal V id in a non-linear element having said non-linear transfer function to form said processed output signal.
References Cited (Backward Citations)
EP0085600A1
Cited
US4462001A
Cited
US4700151A
Cited
US4943783A
Cited
US5132639A
Cited
US5049832A
Cited
US5321849A
Cited
US5455538A
Cited
US5524286A
Cited
US5610554A
Cited
US5675285A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-08-22 | 2004-02-21 | 2004-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-22 | 2008-02-21 | 2008-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-22 | 2012-02-21 | 2012-08-22 | $7700.00 | Window Closed / Lapsed |