Patent EP0367457A2 successfully refreshed from Google Patents.
EP0367457A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A feed forward linear amplifier
Assignee: AT&T Inc
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Filing: 1989-10-20
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Granted: —
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Expires: 2009-10-20
Abstract
Abstract A feed forward circuit receives an input signal (S) having at least one carrier therein in a prescribed frequency range. The input signal is applied to a first circuit path having a power amplifier (110) that produces an output signal with a distortion component and to a second circuit path that delays the input signal without distortion. The output signal of the first circuit path is combined with the output signal of the second circuit path to form a signal representative of the distortion component of the first circuit path output signal and the distortion component representative signal is subtracted from the output signal of the first circuit path to cancel the distortion component therein. The prescribed frequency range of the first circuit path output is scanned to detect a carrier signal and the amplitude and phase of the signal in the first circuit path is modified to minimize the magnitude of the detected carrier in the distortion representative signal.
Inventors
- 👤 Robert E. Myer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 08:14
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/32; H03F1/3223; H03F1/3229; H03F1/3235; H03F2201/00; H03F2201/32; H03F2201/3212
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
232 words
1 . A feed forward circuit comprising: means for receiving one or more input signals in a prescribed frequency range; a first circuit path having an input connected to the receiving means and an output, the first circuit path including power amplifying means responsive to the one or more input signals for generating an output signal having a distortion component; a second circuit path having an input connected to the receiving means and an output, the second circuit path including delay means for transferring the one or more input signals without distortion; means for combining the power amplifying means output signal from the output of the first circuit path with the transferred one or more input signals from the output of the second circuit path to form a signal representative of the distortion component of the first circuit path output signal; and means for subtracting the signal from the combining means from the output signal of the first circuit path to reduce the distortion component of the output signal of the first path; CHARACTERIZED BY means (117, 150, 140) for detecting a first type signal within the prescribed frequency range; and means (105) responsive to the magnitude of the detected first type signal from the combining means for modifying the amplitude and phase of the first circuit path to reduce the magnitude of the detected first type signal from the combining means.
Claim 2
Dependent Claim
232 words
1 . A feed forward circuit comprising: means for receiving one or more input signals in a prescribed frequency range; a first circuit path having an input connected to the receiving means and an output, the first circuit path including power amplifying means responsive to the one or more input signals for generating an output signal having a distortion component; a second circuit path having an input connected to the receiving means and an output, the second circuit path including delay means for transferring the one or more input signals without distortion; means for combining the power amplifying means output signal from the output of the first circuit path with the transferred one or more input signals from the output of the second circuit path to form a signal representative of the distortion component of the first circuit path output signal; and means for subtracting the signal from the combining means from the output signal of the first circuit path to reduce the distortion component of the output signal of the first path; CHARACTERIZED BY means (117, 150, 140) for detecting a first type signal within the prescribed frequency range; and means (105) responsive to the magnitude of the detected first type signal from the combining means for modifying the amplitude and phase of the first circuit path to reduce the magnitude of the detected first type signal from the combining means.
Claim 3
Dependent Claim
71 words
A feed forward circuit according to claim 1 wherein the means for modifying the amplitude and phase of signals in the first circuit path is CHARACTERIZED BY means (310, 417, 420, 427, 430) responsive to the detected first type signal from the combining means for adjusting the amplitude and phase of signals in the first circuit path to minimize the magnitude of the detected first type signal from the combining means.
Claim 4
Dependent Claim
110 words
A feed forward circuit according to claim 2 wherein the means for adjusting the amplitude and phase of signals in the first circuit path is CHARACTERIZED BY means (310, 420) for determining the magnitude of the detected first type signal from the combining means and means (FIG. 5) responsive to the determined magnitude of the detected first type signal for sequentially changing the amplitude of signals in the first circuit path to reduce the determined magnitude of the first type signal from the combining means and changing the phase of signals in the first circuit path to reduce the determined magnitude of the first type signal from the combining means.
Claim 5
Dependent Claim
52 words
A feed forward circuit according to claim 3 wherein the means for detecting a first type signal in the prescribed frequency range is CHARACTERIZED BY means (117, 140, 142, 145) for scanning the output of the substracting means over the prescribed frequency range to detect a signal exceeding a first predetermined threshold.
Claim 6
Dependent Claim
20 words
A feed forward circuit according to claim 4 further CHARACTERIZED IN THAT the first type signal is a carrier signal.
Claim 7
Dependent Claim
129 words
A feed forward circuit according to claims 1, 2, 3, 4, or 5 wherein the means for subtracting the signal from the combining means from the signal at the output of the first path having the distortion component is CHARACTERIZED BY means (122) for modifying the amplitude and phase of the signal from the combining means; means (130, 137,145, 150, 140) connected to the output of the subtracting means for detecting a second type signal associated with the detected first type within the prescribed frequency range; and means (122) responsive to the magnitude of the detected second type signal for adjusting the amplitude and phase of the signal from the combining means to reduce the magnitude of the detected second type signal at the output of the subtracting means.
Claim 8
Dependent Claim
111 words
A feed forward circuit according to claim 6 wherein the means for adjusting the amplitude and phase of the signal from the combining means is CHARACTERIZED BY means (310,448) for determining the magnitude of the detected second type signal from the subtracting means and means (310, FIG. 6) responsive to the determined magnitude of the detected second type signal for sequentially changing the amplitude of the signal from the combining means to reduce the determined magnitude of the detected second type signal from the subtracting means and changing the phase of the signal from the combining means to reduce the determined magnitude of the second type signal from the subtracting means.
Claim 9
Dependent Claim
58 words
A feed forward circuit according to claim 7 wherein the means for detecting the second type signal in the prescribed frequency range is CHARACTERIZED BY means (134, 137, 140, 142, 145, 150) for scanning the output of the subtracting means over the prescribed frequency range to detect a signal having a magnitude between second and third predetermined thresholds.
Claim 10
Dependent Claim
20 words
A feed forward circuit according to claim 8 CHARACTERIZED IN THAT the second type signal is an intermodulation products signal.
Claim 11
Dependent Claim
180 words
A feed forward circuit according to claim 1 wherein the means for detecting a first type signal within the prescribed frequency range is CHARACTERIZED IN THAT the means for detecting a first type signal within the prescribed frequency range comprises means (310, 805, 807, 810) for detecting a frequency within the prescribed frequency range having no signal thereat above a predetermined first threshold; means (310, 815) responsive to the detection of said frequency for inserting a pilot signal at said detected frequency at the input signal receiving means; and the means responsive to the magnitude of the detected first type signal from the combining means for modifying the amplitude and phase of the first circuit path to reduce the magnitude of the detected first type signal from the combining means comprises means (310, 817, 820, 827, 830) responsive to the magnitude of the inserted pilot signal at the output of the combining means for modifying the amplitude and phase of the first circuit path to reduce the magnitude of the inserted pilot signal at the output of the combining means.
Claim 12
Dependent Claim
158 words
A feed forward circuit according to claim 1 wherein the means for subtracting the signal from the combining means from the signal at the output of the first path having the distortion component is CHARACTERIZED BY means (922) for modifying the amplitude and phase of the signal from the combining means; means (930, 937, 945, 950, 940) connected to the output of the subtracting means for detecting a frequency within the prescribed frequency range having no signal thereat above a predetermined second threshold; means (940, 942, 972) responsive to the detection of said frequency for inserting a pilot signal at said detected frequency into the first circuit path; and means (940, 922) responsive to the magnitude of the inserted pilot signal at the output of the subtracting means for modifying the amplitude and phase of the output signal from the combining means to reduce the magnitude of the inserted pilot signal at the output of the subtracting means.
References Cited (Backward Citations)
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