Waveforms for envelope tracking transmitter
First Claim
1. A method comprising:
- generating a modulated signal in a carrier frequency indicative of baseband data;
providing a supply voltage for adjusting the modulated signal for providing a transmission signal for transmission in a transmitter for transmitting information, wherein the baseband data is indicative of the information;
providing a voltage reference level for controlling a gain in said adjusting;
modifying the supply voltage with a waveform indicative of an envelope of the baseband data; and
imposing a lower limit to the waveform prior to providing the waveform for said modifying such that the supply voltage is always greater than a predetermined value, wherein said lower limit is computed at least partly based on transmit power level information, indicative of the voltage reference level.
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Accused Products
Abstract
A method and device for improving the efficiency of an envelope tracking transmitter in which a power amplifier for coupling modulated signals in a carrier frequency to an antenna for transmission. The transmitter comprises a power supply for providing a supply voltage to the power amplifier, and a computation means for providing a waveform indicative of the envelope of the modulated signal to the power supply in order to modify the supply voltage. A lower limit is imposed to the waveform so that the supply voltage to the power supply is always greater than a predetermined value. Moreover, when information is transmitted in times slots which are started and ended by ramp periods, a constant signal, based on the root-mean-square value of the waveform, is used to modify the waveform so that the supply voltage to the power amplifier includes a constant voltage level in the ramp periods.
79 Citations
17 Claims
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1. A method comprising:
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generating a modulated signal in a carrier frequency indicative of baseband data; providing a supply voltage for adjusting the modulated signal for providing a transmission signal for transmission in a transmitter for transmitting information, wherein the baseband data is indicative of the information; providing a voltage reference level for controlling a gain in said adjusting; modifying the supply voltage with a waveform indicative of an envelope of the baseband data; and imposing a lower limit to the waveform prior to providing the waveform for said modifying such that the supply voltage is always greater than a predetermined value, wherein said lower limit is computed at least partly based on transmit power level information, indicative of the voltage reference level. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transmitter comprising:
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a signal processor for providing baseband data indicative of information for transmission; a modulating mechanism, responsive to the baseband data, for providing a modulated signal in a carrier frequency indicative of the baseband data; an amplifier, responsive to the modulated signal, for providing transmission signals for transmission; a power control module for providing a voltage reference level to the amplifier for controlling a gain of the amplifier and for providing transmit power level information; a power supply for providing a supply voltage to the amplifier; a computation module, responsive to the baseband data, for providing a waveform to the power supply for modifying the supply voltage, the waveform indicative of an envelope of the baseband data, wherein a lower limit is imposed to the waveform prior to providing the waveform to the power supply such that the supply voltage to the amplifier is always greater than a predetermined value, and wherein the lower limit is computed at least partly based on the transmit power level information provided by the power control module. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A transmitter for transmitting information comprising:
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means, for providing baseband data indicative of the information; means, responsive to the baseband data, for providing a modulated signal in a carrier frequency indicative of the baseband data; means for amplifying the modulated signal for providing transmission signals for transmission; means for controlling a gain of said amplifying means and for providing transmit power level information; means, for providing a supply voltage to said amplifying means; means, responsive to the baseband data, for providing a waveform to said voltage supplying means for modifying the supply voltage, the waveform indicative of an envelope of the baseband data, wherein a lower limit is imposed to the waveform prior to providing the waveform to said voltage supplying means such that the supply voltage to said amplifying means is always greater than a predetermined value, and wherein the lower limit is computed at least partly based on the transmit power level information, provided by said controlling means. - View Dependent Claims (17)
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Specification