Method for predistortion of a signal, and a transmitting device having digital predistortion, in particular for mobile radio
First Claim
1. A method for predistortion of a signal, comprising:
- providing at least one amplifier circuit configured to assume one operating state from a set of a first operating state and at least one second operating state, with the first operating state and the at least one second operating state being characterized by at least one characteristic variable;
providing a discrete-value and discrete-time modulation signal with a first component and a second component;
providing a first table comprising a plurality of predistortion coefficients;
providing at least one second table comprising a plurality of predistortion coefficients;
producing a power word derived from an output power of a transmission signal or from the first component;
determining the operating state of the at least one amplifier circuit with recording of the characteristic variable;
comparing the power word with a reference value and producing a first result or a second result depending on the comparison;
selection of one table from the first and the at least one second table depending on the determined operating state;
selecting a predistortion coefficient from the selected table depending on the power word and the first component when the comparison has produced the first result; and
distorting at least one component of the first component or the second component with the predistortion coefficient when the comparison has produced the first result.
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Accused Products
Abstract
A method is proposed for signal processing with predistortion. An amplifier circuit is provided for this purpose, whose operating states are characterized by at least one characteristic variable. A digital modulation signal having two components (R, φ), as well as a power word (LS), derived from the first component (R), are produced, and an operating state of the at least one amplifier circuit is then determined by recording of the characteristic variable. The power word (LS) is compared with the reference value and used to decide whether to predistort the first and/or the second component. A table with various predistortion coefficients is selected from at least two tables, depending on the operating state of the amplifier circuit. One predistortion coefficient is then determined from the selected table with the produced power word (LS) and the first component (R), and the predistortion coefficient is used for predistortion.
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Citations
28 Claims
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1. A method for predistortion of a signal, comprising:
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providing at least one amplifier circuit configured to assume one operating state from a set of a first operating state and at least one second operating state, with the first operating state and the at least one second operating state being characterized by at least one characteristic variable;
providing a discrete-value and discrete-time modulation signal with a first component and a second component;
providing a first table comprising a plurality of predistortion coefficients;
providing at least one second table comprising a plurality of predistortion coefficients;
producing a power word derived from an output power of a transmission signal or from the first component;
determining the operating state of the at least one amplifier circuit with recording of the characteristic variable;
comparing the power word with a reference value and producing a first result or a second result depending on the comparison;
selection of one table from the first and the at least one second table depending on the determined operating state;
selecting a predistortion coefficient from the selected table depending on the power word and the first component when the comparison has produced the first result; and
distorting at least one component of the first component or the second component with the predistortion coefficient when the comparison has produced the first result. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A transmitting device, comprising:
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a signal processing device configured to produce and emit a discrete-value and discrete-time modulation signal with a first component and a second component, and configured to emit a power control signal based on the first component at a control output thereof;
an amplifier circuit configured to assume one operating state from a set of a first operating state and at least one second operating state, with the first operating state and the at least one second operating state being characterized by at least one characteristic variable;
a predistortion device comprising;
a control input and a selection input;
a first signal path configured to pass the first and second components of the modulation signal;
a memory comprising a plurality of predistortion coefficients stored therein, in which a first number of predistortion coefficients are associated with the first operating state of the amplifier circuit, and in which at least one second number of predistortion coefficients are associated with the at least one second operating state;
an address unit configured to select the first or second number of predistortion coefficients depending on a selection word, which is derived from the at least one characteristic variable at the selection input;
a second signal path comprising switching elements for distortion of at least one component applied thereto with a predistortion coefficient from the selected number of predistortion coefficients depending on a control signal provided at the control input and the component;
wherein the predistortion device is configured to select the first or second signal path depending on the signal which is provided to the control input;
a modulation unit coupled to the output of the predistortion unit, and configured to convert signals provided by the predistortion device to a carrier signal, and emit the carrier signal at an output thereof which is coupled to the amplifier circuit;
a power control unit connected to the signal processing device, the power control unit configured to emit the control signal for predistortion and emit a gain adjustment signal from the power control signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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Specification