Method and device for envelope tracking

Abstract

The embodiment of the invention provides a method for envelope tracking, which comprises the following steps of: calculating an amplitude abs_data (t) of an input signal, abs_data (t)=(I2(t)+Q2(t))<1 / 2>, wherein I(t) and Q(t) are amplitudes of two paths of in-phase and orthogonal signals of the input signals respectively; calculating the maximum numerical value in continuous M data and taking the numerical value as an envelope (qam_data_envelope) of the data; carrying out smooth treatment on an extracted signal envelope; and increasing a margin for the envelope signal which is subjected to the smooth treatment so that a peak value signal can be covered by the envelope. Due to the adoption of the scheme provided by the invention, the signal envelope is obtained through carrying out the smooth treatment on the signal twice so that the tracking on the signal can be effectively covered and violent vibration cannot be caused, and the peak-to-average ratio (RAP) of the obtained signal envelope is also reduced.

Description

technical field [0001] The present invention relates to the field of digital communication, in particular, the present invention relates to an envelope tracking method and device. Background technique [0002] With the rapid development of the third generation wireless communication system, wideband radio frequency power amplifier will play an increasingly important role. The use of non-constant-envelope modulation means that RF amplifiers usually need to adopt a power back-off method to meet the linearity requirements of the system. However, in order to improve the efficiency of the power amplifier, it is usually required to work in a saturated state, which will inevitably lead to serious nonlinearity. The nonlinear distortion of the RF power amplifier will expand the spectrum of the original signal, thereby causing greater interference to adjacent channels. The linearization of RF power amplifier is an effective method to solve the contradiction between its efficiency an...

AI Technical Summary

Problems solved by technology

Because of the incompleteness or nonlinearity in the tracking behavior of the power supply, the output voltage obtained by the power supply is only a rough approximation of the envelope level actually required by the power amplifier. If the power supply output does not meet the amplifier needs, the distortion generated by the amplifier will greatly increase

The most typical situation is that the extracted signal envelope cannot cover the original signal envelope, so that the power supply has already caused distortion to the signal

In addition, envelope tracking adjusts the supply voltage to the power amplifier through the required instantaneous RF output power, but the rate of change of the instantaneous output power depends on the bandwidth of the amplitude component of the modulation. As the bandwidth of the signal system becomes wider and wider, the modulation The bandwidth of the amplitude component of , is also increasing, and it is more difficult for the envelope power modulator to work at this time

Images