US 2003/0198300 A1 · Waveforms for envelope tracking transmitter

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.

Claims15

Dependent claims

A method of improving the efficiency of a transmitter for transmitting information in a carrier frequency via an antenna, wherein the transmitter includes:

a signal processor for providing baseband data indicative of the information,
a modulating mechanism, responsive to the baseband data, for providing a modulated signal in the carrier frequency indicative of the baseband data;
an amplifier, responsive to the modulated signal, for providing a transmission signal to the antenna for transmission;
a power supply for providing a supply voltage to the amplifier;
and
a computation means, 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 modulated signal, said method characterized by
modifying the waveform by imposing a lower limit thereto prior to providing the waveform to the power supply such that the supply voltage to the amplifier is always greater than a predetermined value.

4 more elements

A device for improving the efficiency of a transmitter system for transmitting information in a carrier frequency via an antenna, wherein the transmitter system includes:

a signal processor for providing baseband data indicative of the information;
a modulating mechanism, responsive to the baseband data, for providing a modulated signal in the carrier frequency indicative of the baseband data;
a transmitter, coupled to the antenna, for transmitting the information in the carrier frequency, wherein the transmitter comprises an amplifier, responsive to the modulated signal, for providing transmission signals to the antenna for transmission;
a power supply for providing a supply voltage to the amplifier;
and
a computation means, 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 modulated signal, said device characterized by
means, responsive to the waveform, for imposing a lower limit 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.

4 more elements

Dependencies are inferred from the claim text.

Waveforms for envelope tracking transmitter

Life of this patent

Waveforms for envelope tracking transmitter

Life of this patent

Abstract

Claims15