Systems and methods for power control in a multiple standard mobile transmitter

摘要

A transmitter adjusts a transmitted power level by modifying a control input of a variable gain amplifier. A power amplifier control system includes an envelope extractor, an error extractor, and a feed-forward multiplier. The envelope extractor receives data signal inputs and computes the envelope of the combined signal. The error extractor generates an error signal as a function of the combined signal and the output power generated by the power amplifier. The feed-forward multiplier generates a modified error signal that is responsive to a function of the gain in a feedback path. A corresponding method for controlling a power level is also disclosed. In some embodiments, a transmit chain with a power control loop is used to adjust the transmit signal power applied at an input of a variable gain amplifier. A corresponding method for adjusting the transmit signal power level is also included.

主权项

1. A transmitter having a transmit signal power control system suitable for operating under multiple communication protocols independent of a modulation data envelope, the transmitter comprising:
an envelope extractor coupled to an in-phase digital signal input and a quadrature-phase digital signal input, the envelope extractor configured to compute an instantaneous value of an envelope of a combined data signal at an envelope extractor output; an error extractor coupled to receive the envelope extractor output and to receive a digital representation of the output power generated by a power amplifier as modified by a feedback multiplier, the error extractor generating an error signal at an extractor output; and a feed-forward multiplier coupled to the extractor output and configured to generate a modified error signal at a feed-forward multiplier output.