Envelope Tracking Signal Bandwidth Control

摘要

An envelope tracking circuit for a transmit and receive path for a telecommunications device includes a filter to reduce the bandwidth of the transmit signal. The envelope of the filtered signal having the lower bandwidth is used to dynamically modulates the power amplifier voltage supply signal. The filter depends on current instantaneous values and also depends in a nonlinear way on instantaneous past and future values of the envelope tracking signal. The filter may be symmetric about peaks of the transmitted signal.

主权项

1. A system comprising:
an envelope circuit configured to receive a transmit signal and produce an envelope signal representative of an envelope of the transmit signal; a power amplifier configured to amplify the transmit signal; a filter configured to receive the envelope signal and produce a filtered envelope signal, the filter implementing a nonlinear filter function that depends on a current instantaneous value of the envelope signal and depends nonlinearly on past instantaneous values of the envelope signal and future instantaneous values of the envelope signal; an envelope tracking circuit coupled to the filter and responsive to the filter envelope signal and coupled to the power amplifier to provide a power supply signal to power the power amplifier, the envelope tracking circuit producing the power supply signal according to the envelope of the filter output signal.