Logarithmic gain adjuster

摘要

A circuit for multiplying a digital signal by a variable gain, controlled in dependence on a digital gain control value. The circuit comprises: a multiplier input for receiving the digital signal; a multiplier output for outputting the digital signal multiplied by the gain; a plurality of multiplier stages each arranged to multiply by a respective predetermined multiplication factor; and switching circuitry arranged so as to apply selected ones of the multiplier stages in a multiplication path between the input and output, in dependence on the digital gain control value. The multiplication factors are arranged such that binary steps in the digital gain control value result in logarithmic steps in said gain.

主权项

1. A circuit for multiplying a digital signal by a variable gain controlled in dependence on a digital gain control value, comprising:
a multiplier input for receiving the digital signal; a multiplier output for outputting the digital signal multiplied by the gain; a plurality of multiplier stages each arranged to multiply the digital signal by a respective predetermined multiplication factor; and switching circuitry arranged so as to apply selected ones of said multiplier stages in a multiplication path between said input and said output, in dependence on the digital gain control value; wherein said multiplication factors are arranged such that binary steps in the digital gain control value result in logarithmic steps in said gain.