Patent US5204881A successfully refreshed from Google Patents.
US5204881A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for set-up of transmitters in high capacity digital radio links
Assignee: Alcatel Lucent Italia SpA
•
Filing: 1990-12-19
•
Granted: 1993-04-20
•
Expires: 2010-12-19
Abstract
Abstract The invention relates to a system for initializing transmitters in high capacity digital radio links, in which a digital signal with QAM (Quadrature Amplitude Modulation) modulation is transmitted over a radio frequency carrier wave. The initialization of the transmitter is accomplished by generating a plurality of sinusoidal signals (tones), adding those tones together to simulate a digital singal to be transmitted, sending the simulated digital signal through the transmitter, and adjusting the transmitter to compensate for the intermodulation odd order products developed as a result of the nonlinearity of the power amplifier in the transmitter.
Inventors
- 👤 Lorenzo Cardini
- 👤 GianCarlo Perego
- 👤 Rocco Nobili
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:15
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/36; H04L27/362
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
149 words
A method for initializing a transmitter used in a high capacity digital radio link in which multilevel QAM digital signals are sent on a carrier wave, said initializing being accomplished by: (a) generating a test signal which simulates the digital signal to be transmitted, said test signal being generated by selectively summing four sinusoidal signals amplitude-modulated by a square wave with a variable duty cycle and amplitude, said test signal being adjusted to obtain a signal having a ratio of peak power/mean power which is equal to that of the digital signal to be transmitted, (b) sending said test signal through the transmitter, said transmitter including a power amplifier which has a nonlinear behavior and distorts signals passing therethrough, and (c) adding pre-distortion signals to the digital signals sent through the power amplifier to compensate for the distortion caused by the non-linearities in the power amplifier of the transmitter.
Claim 2
Independent Claim
149 words
A method for initializing a transmitter used in a high capacity digital radio link in which multilevel QAM digital signals are sent on a carrier wave, said initializing being accomplished by: (a) generating a test signal which simulates the digital signal to be transmitted, said test signal being generated by selectively summing four sinusoidal signals amplitude-modulated by a square wave with a variable duty cycle and amplitude, said test signal being adjusted to obtain a signal having a ratio of peak power/mean power which is equal to that of the digital signal to be transmitted, (b) sending said test signal through the transmitter, said transmitter including a power amplifier which has a nonlinear behavior and distorts signals passing therethrough, and (c) adding pre-distortion signals to the digital signals sent through the power amplifier to compensate for the distortion caused by the non-linearities in the power amplifier of the transmitter.
Claim 3
Dependent Claim
50 words
A method as recited in claim 1, wherein the adjustment of the test signal is accomplished by adjusting the amplitude and duration of the square wave so that the test signal has a ratio of peak power/mean power which is equal to that of the digital signal to be transmitted.
Claim 4
Independent Claim
105 words
A device for initializing a transmitter used in a high capacity data link in which digital signals are sent on a carrier wave, comprising: (a) a test signal generator for generating a test signal, said test signal generator comprising four oscillators for producing said sinusoidal signals, a summator for summing said sinusoidal signals, an amplitude modulator for modulating the summed sinusoidal signals and a square wave generator adjustable in amplitude and duration for adjusting said amplitude modulator, and (b) a pre-distorter signal generator for adding distortion to the digital signals to be transmitted which compensates for distortion introduced by a power amplifier in the transmitter.
Claim 5
Independent Claim
105 words
A device for initializing a transmitter used in a high capacity data link in which digital signals are sent on a carrier wave, comprising: (a) a test signal generator for generating a test signal, said test signal generator comprising four oscillators for producing said sinusoidal signals, a summator for summing said sinusoidal signals, an amplitude modulator for modulating the summed sinusoidal signals and a square wave generator adjustable in amplitude and duration for adjusting said amplitude modulator, and (b) a pre-distorter signal generator for adding distortion to the digital signals to be transmitted which compensates for distortion introduced by a power amplifier in the transmitter.
References Cited (Backward Citations)
US4291277A
Cited
US4462001A
Cited
US4890300A
Cited
US4890301A
Cited
US4991164A
Cited
US4993021A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-19 | 1996-10-19 | 1997-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-19 | 2000-10-19 | 2001-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-19 | 2004-10-19 | 2005-04-20 | $7700.00 | Window Closed / Lapsed |