US5351016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptively self-correcting modulation system and method
Assignee: Ericsson Inc
•
Filing: 1993-05-28
•
Granted: 1994-09-27
•
Expires: 2013-05-28
Abstract
Abstract A self-adjusting quadrature modulator and modulation method improve the accuracy with which digital data is impressed on an RF carrier, which is particularly useful for systems having Viterbi, echo-integrating demodulators and for systems using subtractive CDMA techniques. The method and apparatus involve receiving one's own transmission with a suitable modulation assessment receiver and determining the modulation error relative to the theoretically perfect transmission expected by the receiver. The measured error is used to adjust the modulation to minimize the error. The modulation assessment receiver may use log-polar signal processing to measure phase and (log)amplitude instead of cartesian I and Q components, and then convert to cartesian form. In addition, correction factors determined by the modulation assessment receiver can be directly identified with certain transform components produced by the Fast Walsh Transform.
Inventors
- 👤 Paul W. Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:20
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3282; H03C; H03C3/00; H03C3/38; H03C3/40; H03C3/406; H03F1/3247; H03F1/3294; H04; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2032; H04L27/2053; H04L27/206; H04L27/2067; H04L27/2071; H03F2200/00; H03F2200/331
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
199 words
An adaptively precompensated quadrature modulator for accurately forming a modulated transmitted signal, comprising: first digital signal processing means for applying correction factors to uncorrected samples of an in-phase modulation waveform and a quadrature modulation waveform to generate corrected samples and for converting corrected samples into a corrected in-phase modulation waveform and a corrected quadrature modulation waveform; a quadrature modulator for impressing the corrected in-phase modulation waveform on a substantially cosinusoidal carrier wave and for impressing the corrected quadrature modulation waveform on a substantially sinusoidal carrier wave, the quadrature modulator producing a modulated output signal; transmitter means for upconverting and amplifying the modulated output signal of said quadrature modulator to a predetermined transmission frequency and power level, the transmitter means producing the modulated transmitted signal; modulation assessment receiving means, coupled to said transmitter means, for generating digitized samples of the modulated transmitted signal; and second digital signal processing means, in communication with said first digital signal processing means and with said modulation assessment receiving means, for determining the correction factors based on said digitized samples generated by said modulation assessment receiving means and on the uncorrected samples and for communicating the correction factors to the first digital signal processing means.
Claim 2
Dependent Claim
199 words
An adaptively precompensated quadrature modulator for accurately forming a modulated transmitted signal, comprising: first digital signal processing means for applying correction factors to uncorrected samples of an in-phase modulation waveform and a quadrature modulation waveform to generate corrected samples and for converting corrected samples into a corrected in-phase modulation waveform and a corrected quadrature modulation waveform; a quadrature modulator for impressing the corrected in-phase modulation waveform on a substantially cosinusoidal carrier wave and for impressing the corrected quadrature modulation waveform on a substantially sinusoidal carrier wave, the quadrature modulator producing a modulated output signal; transmitter means for upconverting and amplifying the modulated output signal of said quadrature modulator to a predetermined transmission frequency and power level, the transmitter means producing the modulated transmitted signal; modulation assessment receiving means, coupled to said transmitter means, for generating digitized samples of the modulated transmitted signal; and second digital signal processing means, in communication with said first digital signal processing means and with said modulation assessment receiving means, for determining the correction factors based on said digitized samples generated by said modulation assessment receiving means and on the uncorrected samples and for communicating the correction factors to the first digital signal processing means.
Claim 3
Dependent Claim
44 words
The adaptively precompensated quadrature modulator of claim 1, wherein said first digital signal processing means includes at least one digital-to-analog converter for converting the corrected samples to said in-phase modulation waveform and quadrature modulation waveform impressed by said quadrature modulator on said carrier waves.
Claim 4
Dependent Claim
18 words
The adaptively precompensated quadrature modulator of claim 2, wherein said digital-to-analog converter uses substantially highly oversampled delta-sigma modulation.
Claim 5
Dependent Claim
27 words
The adaptively precompensated quadrature modulator of claim 1, wherein said digitized samples generated by said modulation assessment receiving means comprise samples in, alternatively, polar and log-polar formats.
Claim 6
Dependent Claim
29 words
The adaptively precompensated quadrature modulator of claim 4, wherein said second digital signal processing means converts said digitized samples generated by said modulation assessment receiving means to cartesian format.
Claim 7
Dependent Claim
20 words
The adaptively precompensated quadrature modulator of claim 1, wherein said in-phase and quadrature modulation waveforms comprise a spread-spectrum coded signal.
Claim 8
Dependent Claim
24 words
The adaptively precompensated quadrature modulator of claim 6, wherein said spread-spectrum coded signal comprises a sum of a plurality of second spread-spectrum coded signals.
Claim 9
Dependent Claim
24 words
The adaptively precompensated quadrature modulator of claim 7, wherein said second digital signal processing means performs a Walsh transform in determining said correction factors.
Claim 10
Dependent Claim
21 words
The adaptively precompensated quadrature modulator of claim 7, wherein said second spread-spectrum coded signals include a plurality of [128,7] Walsh-Hadamard codewords.
Claim 11
Dependent Claim
21 words
The adaptively precompensated quadrature modulator of claim 7, wherein said second spread-spectrum coded signals include a plurality of [128,8] Walsh-Hadamard codewords.
Claim 12
Dependent Claim
24 words
The adaptively precompensated quadrature modulator of claim 1, wherein said second digital signal processing means performs a Walsh transform in determining said correction factors.
Claim 13
Dependent Claim
56 words
The adaptively precompensated quadrature modulator of claim 1, wherein said modulated output signal comprises one of a Quadrature Phase Shift Keying signal, an Offset Quadrature Phase Shift Keying signal, a Shaped Offset Quadrature Phase Shift Keying signal, a Quadrature Amplitude Modulation signal, an Offset Quadrature Amplitude Modulation signal, and a Shaped Offset Quadrature Amplitude Modulation signal.
Claim 14
Dependent Claim
153 words
An adaptively precompensated quadrature modulation method for accurately forming a modulated signal, comprising the steps of: (a) applying a set of correction factors to uncorrected in-phase and quadrature modulation waveform samples to produce corrected in-phase and quadrature modulation samples; (b) forming a corrected in-phase modulation waveform from the corrected in-phase modulation samples and modulating a substantially cosinusoidal carrier wave with the corrected in-phase modulation waveform, forming a corrected quadrature modulation waveform from the corrected quadrature modulation samples and modulating a substantially sinusoidal carrier wave with the corrected quadrature modulation waveform, and forming a modulated output signal by summing the modulated cosinusoidal and sinusoidal carrier waves; (c) forming a modulated transmitted signal by upconverting and amplifying the modulated output signal to a selected desired transmission frequency and power level; (d) collecting digital samples of the modulated transmitted signal; and (e) determining the set of correction factors from said digital samples and the uncorrected samples.
Claim 15
Dependent Claim
153 words
An adaptively precompensated quadrature modulation method for accurately forming a modulated signal, comprising the steps of: (a) applying a set of correction factors to uncorrected in-phase and quadrature modulation waveform samples to produce corrected in-phase and quadrature modulation samples; (b) forming a corrected in-phase modulation waveform from the corrected in-phase modulation samples and modulating a substantially cosinusoidal carrier wave with the corrected in-phase modulation waveform, forming a corrected quadrature modulation waveform from the corrected quadrature modulation samples and modulating a substantially sinusoidal carrier wave with the corrected quadrature modulation waveform, and forming a modulated output signal by summing the modulated cosinusoidal and sinusoidal carrier waves; (c) forming a modulated transmitted signal by upconverting and amplifying the modulated output signal to a selected desired transmission frequency and power level; (d) collecting digital samples of the modulated transmitted signal; and (e) determining the set of correction factors from said digital samples and the uncorrected samples.
Claim 16
Dependent Claim
26 words
The method of claim 13, wherein the forming step (b) includes the step of converting the corrected in-phase and quadrature waveform samples to an analog form.
Claim 17
Dependent Claim
15 words
The method of claim 14, wherein said converting step comprises substantially highly oversampled delta-sigma modulation.
Claim 18
Dependent Claim
15 words
The method of claim 13, wherein said digitized samples comprise, alternatively, polar and log-polar representations.
Claim 19
Dependent Claim
22 words
The method of claim 16, wherein step (c) includes the step of converting the, alternatively, polar and log-polar representations to cartesian representation.
Claim 20
Dependent Claim
15 words
The method of claim 13, wherein the modulated output signal comprises a spread-spectrum coded signal.
Claim 21
Dependent Claim
25 words
The method of claim 18, wherein step (e) comprises the step of performing a Walsh transform on said digitized samples to determine said correction factors.
Claim 22
Dependent Claim
17 words
The method of claim 18, wherein said spread-spectrum coded signal includes a plurality of [128,7] Walsh-Hadamard codewords.
Claim 23
Dependent Claim
16 words
The method of claim 20, wherein said spread-spectrum signal includes a plurality of [128,8] Walsh-Hadamard codewords.
Claim 24
Dependent Claim
53 words
The method of claim 13, wherein said modulated output signal comprises one of a Quadrature Phase Shift Keying signal, an Offset Quadrature Phase Shift Keying signal, a Shaped Offset Quadrature Phase Shift Keying signal, a Quadrature Amplitude Modulation signal, an Offset Quadrature Amplitude Modulation signal, and a Shaped Offset Quadrature Amplitude Modulation signal.
Claim 25
Dependent Claim
25 words
The method of claim 13, wherein step (e) includes the step of performing a Walsh transform on said digitized samples to determine said correction factors.
Claim 26
Dependent Claim
146 words
An adaptively precompensated quadrature modulator for accurately forming a modulated signal, comprising: a first processor that applies correction factors to uncorrected samples of an in-phase modulation waveform and a quadrature modulation waveform, thereby generating corrected samples, and that converts the corrected samples into a corrected in-phase modulation waveform and a corrected quadrature modulation waveform; a quadrature modulator that impresses the corrected in-phase modulation waveform on a substantially cosinusoidal carrier wave and that impresses the corrected quadrature modulation waveform on a substantially sinusoidal carrier wave, thereby producing the modulated signal; a modulation assessment receiver, coupled to the quadrature modulator, that generates digitized samples of the modulated signal; and a second processor that is coupled to the first processor and the modulation assessment receiver, that determines the correction factors based on the digitized samples and the uncorrected samples, and that communicates the correction factors to the first processor.
Claim 27
Dependent Claim
146 words
An adaptively precompensated quadrature modulator for accurately forming a modulated signal, comprising: a first processor that applies correction factors to uncorrected samples of an in-phase modulation waveform and a quadrature modulation waveform, thereby generating corrected samples, and that converts the corrected samples into a corrected in-phase modulation waveform and a corrected quadrature modulation waveform; a quadrature modulator that impresses the corrected in-phase modulation waveform on a substantially cosinusoidal carrier wave and that impresses the corrected quadrature modulation waveform on a substantially sinusoidal carrier wave, thereby producing the modulated signal; a modulation assessment receiver, coupled to the quadrature modulator, that generates digitized samples of the modulated signal; and a second processor that is coupled to the first processor and the modulation assessment receiver, that determines the correction factors based on the digitized samples and the uncorrected samples, and that communicates the correction factors to the first processor.
Claim 28
Dependent Claim
35 words
The adaptively precompensated quadrature modulator of claim 24, wherein the first processor includes at least one digital-to-analog converter that converts the corrected samples into the corrected in-phase modulation waveform and the corrected quadrature modulation waveform.
References Cited (Backward Citations)
US4581749A
Cited
US4856025A
Cited
US4953182A
Cited
US4899367A
Cited
US5048059A
Cited
US4985688A
Cited
US5148448A
Cited
US5148373A
Cited
US5105445A
Cited
US5084669A
Cited
US5020076A
Cited
US5151919A
Cited
US5218619A
Cited
US5293406A
Cited
US5249200A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-09-26 | 1998-03-28 | 1998-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-26 | 2002-03-28 | 2002-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-26 | 2006-03-28 | 2006-09-27 | $7700.00 | Window Closed / Lapsed |