Transmission device with digital predistortion, and method for regulating predistortion in a transmission device
First Claim
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1. A transmission device, comprising:
- a processor unit for providing a first discrete-value component (I) of a baseband signal (DAT1) at a first output and a second discrete-value component (Q) of the baseband signal (DAT1) at a second output;
a predistortion unit, operatively associated with the outputs of the processor unit, having a first and a second input and having a first and a second output, wherein the predistortion unit has a coefficient unit for ascertaining one or more predistortion coefficients (KOEFF1), which represent complex values, on the basis of a control signal (CONT1) at a control input on the coefficient unit, a level for the first component (I), which is applied to the first input, and a level for the second component (Q), which is applied to the second input, wherein the predistortion unit has a multiplication unit operable to output an output signal (DAT2), which is derived from the first component (I), which is applied to the first input, and from the second component (Q), which is applied to the second input, of the baseband signal (DAT1), and from the predistortion coefficient (KOEFF1), with a first discrete-value component (I2) at the first output and with a second discrete-value component (Q2) at the second output;
respective digital/analog conversion devices operatively associated with the outputs on the predistortion unit;
a modulator unit having a local oscillator input for supplying a local oscillator signal (OSC), a first input for supplying a first continuous-value signal, a second input for supplying a second continuous-value signal, which are coupled to respective outputs of the digital/analog conversion devices, and an output for outputting a complex-form output signal;
an amplification device with regulatable gain, whose input is operatively associated with the output of the modulator unit, wherein the predistortion unit has a first and a second operating state and is configured to respectively output signals (I), (O) at the first and second outputs in the first operating state and to respectively output the first and second components (I2, Q2) of the derived output signal (DAT2) at the first and second outputs in the second operating state, wherein the predistortion unit can be switched to the first or to the second operating state by the first control signal (CONT1) at the control input; and
a power control unit having an input for supplying a discrete-value power control signal (LS) to provide the first control signal (CONT1) at a first output and a second control signal at a second output, the first output being coupled to the control input of the predistortion unit, and the second output being coupled to a control input on the amplification device.
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Abstract
One or more aspects of the present invention relate to a transmission device having a digital predistortion unit which has a control input to which a control signal (CONT1) is applied. The control signal is output by a power control unit which evaluates a power control signal (LS). The predistortion unit distorts a baseband signal which is to be transmitted whenever the linearity of a power amplifier can no longer be observed at the currently required power without predistortion. To this end, the baseband signal is multiplied in complex fashion by a predistortion coefficient which is dependent on the level of the baseband signal.
91 Citations
20 Claims
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1. A transmission device, comprising:
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a processor unit for providing a first discrete-value component (I) of a baseband signal (DAT1) at a first output and a second discrete-value component (Q) of the baseband signal (DAT1) at a second output;
a predistortion unit, operatively associated with the outputs of the processor unit, having a first and a second input and having a first and a second output, wherein the predistortion unit has a coefficient unit for ascertaining one or more predistortion coefficients (KOEFF1), which represent complex values, on the basis of a control signal (CONT1) at a control input on the coefficient unit, a level for the first component (I), which is applied to the first input, and a level for the second component (Q), which is applied to the second input, wherein the predistortion unit has a multiplication unit operable to output an output signal (DAT2), which is derived from the first component (I), which is applied to the first input, and from the second component (Q), which is applied to the second input, of the baseband signal (DAT1), and from the predistortion coefficient (KOEFF1), with a first discrete-value component (I2) at the first output and with a second discrete-value component (Q2) at the second output;
respective digital/analog conversion devices operatively associated with the outputs on the predistortion unit;
a modulator unit having a local oscillator input for supplying a local oscillator signal (OSC), a first input for supplying a first continuous-value signal, a second input for supplying a second continuous-value signal, which are coupled to respective outputs of the digital/analog conversion devices, and an output for outputting a complex-form output signal;
an amplification device with regulatable gain, whose input is operatively associated with the output of the modulator unit, wherein the predistortion unit has a first and a second operating state and is configured to respectively output signals (I), (O) at the first and second outputs in the first operating state and to respectively output the first and second components (I2, Q2) of the derived output signal (DAT2) at the first and second outputs in the second operating state, wherein the predistortion unit can be switched to the first or to the second operating state by the first control signal (CONT1) at the control input; and
a power control unit having an input for supplying a discrete-value power control signal (LS) to provide the first control signal (CONT1) at a first output and a second control signal at a second output, the first output being coupled to the control input of the predistortion unit, and the second output being coupled to a control input on the amplification device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for regulating predistortion for a discrete-value signal (DAT1) in a transmission device, comprising:
multiplying first and second components (I, Q) of the signal (DAT1) by a complex predistortion coefficient (KOEFF1) when a level for an output signal from a regulatable amplification device is exceeded as determined by a control signal (CONT1), where the coefficient (KOEFF1) is dependent on respective levels of the first and second components (I, Q) of the signal (DAT1) and on a control signal (CONT1). - View Dependent Claims (16, 17, 18, 19, 20)
Specification