Patent ID: 6278324
Filing Date: 2001-08-21
Classification: H03G

Abstract:
An apparatus including an amplifier with a monotonic transfer function, comprising:a control signal generator circuit that following reception of a variable input control signal generates a plurality of continuously variable discrete analog output control signals having a plurality of respective continuously variable output control signal values including a minimum value, one or more successively greater intermediate values and a maximum value; anda variable gain amplifier circuit, coupled to said control signal generator circuit, that following reception of said plurality of continuously variable discrete analog output control signals receives and amplifies an analog input signal and generates an analog output signal, wherein a ratio of said analog output signal and said analog input signal defines a monotonic transfer function, wherein said variable gain amplifier circuit comprisesa variable impedance circuit configured to receive said plurality of continuously variable discrete analog output control signals and in accordance therewith exhibit a corresponding continuously variable circuit impedance, wherein said variable impedance circuit comprisesa plurality of fixed resistive circuit elements, anda plurality of variable resistive circuit elements, wherein respective ones of said plurality of variable resistive circuit elementsreceive respective ones of said plurality of continuously variable discrete analog output control signals,are coupled in series with respective couples of said plurality of fixed resistive circuit elements, andare coupled in parallel with respective couples of said serially coupled variable and fixed resistive circuit elements, andan analog amplifier circuit having an impedance-dependent signal gain, coupled to said variable impedance circuit and configured to receive and amplify said analog input signal and in accordance therewith generate said analog output signal, wherein said monotonic transfer function corresponds to said continuously variable circuit impedance.