DISTORTION COMPENSATION CIRCUIT
First Claim
1. A distortion compensation circuit that compensates for intermodulation distortions occurring in the amplifier by generating intermodulation distortions which have opposite characteristics to the intermodulation distortions occurring in the amplifier, the amplifier being connected to a stage previous to an input terminal of a signal path or to a stage subsequent to an output terminal of the signal path, the distortion compensation circuit comprising:
- a linearizer circuit to generate, in response to an input of a plurality of radio frequency signals through the input terminal, a difference-frequency signal and intermodulation distortions of the radio frequency signals, the linearizer circuit being inserted in the signal path;
a low-pass circuit to block passage of the radio frequency signals and the intermodulation distortions generated by the linearizer circuit and to allow passage of the difference-frequency signal, one end of the low-pass circuit being connected to the signal path; and
an intermodulation distortion adjustment circuit to adjust intermodulation distortions appearing in the signal path by reflecting the difference-frequency signal having passed through the low-pass circuit to return to the linearizer circuit, the intermodulation distortion adjustment circuit being connected between another end of the low-pass circuit and a ground,.whereinthe linearizer circuit includes a diode and a resistor, the diode being connected between the signal path and a ground, the resistor being connected between a DC terminal and the signal path,the low-pass circuit includes a transmission line whose one end is connected to the signal path and another end is connected to the intermodulation distortion adjustment circuit, and an open stub whose one end is connected to the transmission line, each of the transmission line and the open stub having a length of a quarter wavelength at a center frequency of the radio frequency signals, andthe intermodulation distortion adjustment circuit includes a reactance element.
1 Assignment
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Accused Products
Abstract
A distortion compensation circuit includes a low-pass circuit to block the passage of two-wave RF signals and intermodulation distortions and to allow the passage of a difference-frequency signal. The low-pass circuit is connected between a signal path and an intermodulation distortion adjustment circuit.
2 Citations
24 Claims
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1. A distortion compensation circuit that compensates for intermodulation distortions occurring in the amplifier by generating intermodulation distortions which have opposite characteristics to the intermodulation distortions occurring in the amplifier, the amplifier being connected to a stage previous to an input terminal of a signal path or to a stage subsequent to an output terminal of the signal path, the distortion compensation circuit comprising:
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a linearizer circuit to generate, in response to an input of a plurality of radio frequency signals through the input terminal, a difference-frequency signal and intermodulation distortions of the radio frequency signals, the linearizer circuit being inserted in the signal path; a low-pass circuit to block passage of the radio frequency signals and the intermodulation distortions generated by the linearizer circuit and to allow passage of the difference-frequency signal, one end of the low-pass circuit being connected to the signal path; and an intermodulation distortion adjustment circuit to adjust intermodulation distortions appearing in the signal path by reflecting the difference-frequency signal having passed through the low-pass circuit to return to the linearizer circuit, the intermodulation distortion adjustment circuit being connected between another end of the low-pass circuit and a ground,. wherein the linearizer circuit includes a diode and a resistor, the diode being connected between the signal path and a ground, the resistor being connected between a DC terminal and the signal path, the low-pass circuit includes a transmission line whose one end is connected to the signal path and another end is connected to the intermodulation distortion adjustment circuit, and an open stub whose one end is connected to the transmission line, each of the transmission line and the open stub having a length of a quarter wavelength at a center frequency of the radio frequency signals, and the intermodulation distortion adjustment circuit includes a reactance element. - View Dependent Claims (2, 3, 13, 16, 19, 22)
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4. (canceled)
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5. A distortion compensation circuit that compensates for intermodulation distortions occurring in the amplifier by generating intermodulation distortions which have opposite characteristics to the intermodulation distortions occurring in the amplifier, the amplifier being connected to a stage previous to an input terminal of differential signal paths or to a stage subsequent to an output terminal of the differential signal paths, the differential signal paths including a first signal path and a second signal path, the distortion compensation circuit comprising:
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a differential signal converter to convert radio frequency signals, which are input through the input terminal and have different frequencies, into a pair of differential signals, and outputs first radio frequency signals to the first signal path as one part of the differential signals and outputs second radio frequency signals to the second signal path as another part of the differential signals; a linearizer circuit to generate, on the first signal path, a difference-frequency signal and intermodulation distortions of the first radio frequency signals in response to an input of the first radio frequency signals, and to generate, on the second signal path, a difference-frequency signal and intermodulation distortions of the second radio frequency signals in response to an input of the second radio frequency signals, the linearizer circuit being inserted in the differential signal paths; a first low-pass circuit to block passage of the first radio frequency signals and the intermodulation distortions generated on the first signal path and to allow passage of the difference-frequency signal generated on the first signal path, one end of the first low-pass circuit being connected to the first signal path; a second low-pass circuit to block passage of the second radio frequency signals and the intermodulation distortions generated on the second signal path and to allow passage of the difference-frequency signal generated on the second signal path, one end of the second low-pass circuit being connected to the second signal path; a first intermodulation distortion adjustment circuit to adjust intermodulation distortions appearing in the first signal path by reflecting the difference-frequency signal having passed through the first low-pass circuit to return to the linearizer circuit, the first intermodulation distortion adjustment circuit being connected between another end of the first low-pass circuit and a ground; a second intermodulation distortion adjustment circuit to adjust intermodulation distortions appearing in the second signal path by reflecting the difference-frequency signal having passed through the second low-pass circuit to return to the linearizer circuit, the second intermodulation distortion adjustment circuit being connected between another end of the second low-pass circuit and a ground; and a single-phase signal converter to convert the differential signals having been transmitted on the first and second signal paths into single-phase signals, wherein the linearizer circuit includes a diode, a first resistor and a second resistor, the diode being connected between the first and second signal paths, the first resistor being connected between the first signal path and a DC terminal, the second resistor being connected between the second signal path and the ground, the first low-pass circuit includes a first transmission line whose one end is connected to the first signal path and another end is connected to the first intermodulation distortion adjustment circuit, and a first open stub whose one end is connected to said another end of the first transmission line, each of the first transmission line and the first open stub having a length of a quarter wavelength at a center frequency of the first radio frequency signals, the first intermodulation distortion adjustment circuit includes a first reactance element, the second low-pass circuit includes a second transmission line whose one end is connected to the second signal path and another end is connected to the second intermodulation distortion adjustment circuit, and a second open stub whose one end is connected to said another end of the second transmission line, each of the second transmission line and the second open stub having a length of a quarter wavelength at a center frequency of the second radio frequency signals, and the second intermodulation distortion adjustment circuit includes a second reactance element. - View Dependent Claims (6, 9, 11, 15, 18, 21, 23)
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7. A distortion compensation circuit that compensates for intermodulation distortions occurring in the amplifier by generating intermodulation distortions which have opposite characteristics to the intermodulation distortions occurring in the amplifier, the amplifier being connected to a stage previous to an input terminal of differential signal paths or to a stage subsequent to an output terminal of the differential signal paths, the differential signal paths including a first signal path and a second signal path, the distortion compensation circuit comprising:
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a differential signal converter to convert radio frequency signals, which are input through the input terminal and have different frequencies, into a pair of differential signals, and outputs first radio frequency signals to the first signal path as one part of the differential signals and outputs second radio frequency signals to the second signal path as another part of the differential signals; a linearizer circuit to generate, on the first signal path, a difference-frequency signal and intermodulation distortions of the first radio frequency signals in response to an input of the first radio frequency signals, and to generate, on the second signal path, a difference-frequency signal and intermodulation distortions of the second radio frequency signals in response to an input of the second radio frequency signals, the linearizer circuit being inserted in the differential signal paths; a first low-pass circuit to block passage of the first radio frequency signals and the intermodulation distortions generated on the first signal path and to allow passage of the difference-frequency signal generated on the first signal path, one end of the first low-pass circuit being connected to the first signal path; a second low-pass circuit to block passage of the second radio frequency signals and the intermodulation distortions generated on the second signal path and to allow passage of the difference-frequency signal generated on the second signal path, one end of the second low-pass circuit being connected to the second signal path; an intermodulation distortion adjustment circuit to adjust intermodulation distortions appearing in the first and second signal paths by reflecting the difference-frequency signal having passed through the first low-pass circuit to return to the linearizer circuit and also reflecting the difference-frequency signal having passed through the second low-pass circuit to return to the linearizer circuit, the intermodulation distortion adjustment circuit being connected between another end of the first low-pass circuit and another end of the second low-pass circuit; and a single-phase signal converter to convert the differential signals having been transmitted through the first and second signal paths into single-phase signals, wherein the linearizer circuit includes a diode, a first resistor and a second resistor, the diode being connected between the first and second signal paths, the first resistor being connected between the first signal path and a DC terminal, the second resistor being connected between the second signal path and the ground, the first low-pass circuit includes a first transmission line whose one end is connected to the first signal path and another end is connected to one end of the intermodulation distortion adjustment circuit, and a first open stub whose one end is connected to said another end of the first transmission line, each of the first transmission line and the first open stub having a length of a quarter wavelength at a center frequency of the first radio frequency signals, the second low-pass circuit includes a second transmission line whose one end is connected to the second signal path and another end is connected to another end of the intermodulation distortion adjustment circuit, and a second open stub whose one end is connected to said another end of the second transmission line, each of the second transmission line and the second open stub having a length of a quarter wavelength at a center frequency of the second radio frequency signals, and the intermodulation distortion adjustment circuit includes a reactance element. - View Dependent Claims (8, 10, 12, 14, 17, 20, 24)
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Specification