Digital fast dB to gain multiplier for envelope tracking systems

摘要

A digital log gain to digital linear gain multiplier is disclosed. The digital log gain to digital linear gain multiplier includes a log gain splitter adapted to split a log gain input into an integer log part and a remainder log part. A log scale-to-linear scale converter is adapted to output a linear gain value in response to the integer log part and the remainder log part. A gain multiply circuit is adapted to multiply a digital signal by the linear gain value to output a gain-enhanced digital signal.

主权项

1. A digital log gain to digital linear gain multiplier for an envelope tracking system comprising:
a log gain splitter including a floor function circuit adapted to split a log gain value into an integer log part that is less than or equal to the log gain value, and a remainder log part, wherein the floor function circuit outputs the integer log part in response to a scaled log gain value received by the floor function that outputs the integer log part; and an adder circuit coupled to the floor function circuit that outputs the remainder log part by summing the log gain value with the negative of the integer log part; a binary anti-log circuit adapted to receive the integer log part from the log gain splitter and output a binary anti-log value of the integer log part; a log-to-linear look up table (LUT) adapted to receive the remainder log part from the adder circuit and output a LUT value corresponding to the remainder log part; and a converter multiply circuit adapted to multiply the binary anti-log value from the binary anti-log circuit by the LUT value to produce a linear gain value; and a gain multiply circuit adapted to multiply a digital signal having a sample rate of at least 52 MHz by the linear gain value to output a gain-enhanced digital signal.