Waveforms for envelope tracking transmitter

专利名称：Waveforms for envelope tracking

transmitter

发明人：Jorma Matero,Jarkko Kesti申请号：US10127340申请日：20020418

公开号：US20030198300A1公开日：20031023

专利附图：

摘要：A method and device for improving the efficiency of an envelope trackingtransmitter in which a power amplifier for coupling modulated signals in a carrierfrequency to an antenna for transmission. The transmitter comprises a power supply for

providing a supply voltage to the power amplifier, and a computation means forproviding a waveform indicative of the envelope of the modulated signal to the powersupply in order to modify the supply voltage. A lower limit is imposed to the waveformso that the supply voltage to the power supply is always greater than a predeterminedvalue. Moreover, when information is transmitted in times slots which are started andended by ramp periods, a constant signal, based on the root-mean-square value of thewaveform, is used to modify the waveform so that the supply voltage to the poweramplifier includes a constant voltage level in the ramp periods.

申请人：NOKIA CORPORATION

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