Patent ID: 7068108

Claim:
An amplifier apparatus having a gain; said gain being programmable to various values in discrete increments; the apparatus comprising: (a) an operational amplifier device having a first input locus for receiving a first signal, having a second input locus for receiving a second signal and having an output locus for presenting an output signal; (b) a feedback circuit coupled between said output locus and said second input locus; (c) a reference signal source coupled with said first input locus via a supply circuit for presenting a reference signal to said first input locus; (d) a first resistor network coupled between a first signal locus and said first input locus; said first resistor network conveying a first input signal from said first signal locus to said first input locus; said first resistor network comprising a first plurality of parallel-connected first resistors; selected first resistors of said first plurality of parallel-connected resistors being independently switchingly coupled for independently selectable inclusion in a first connecting of said first signal locus with said first input locus; (e) a second resistor network coupled between a second signal locus and said second input locus; said second resistor network conveying a second input signal from said second signal locus to said second input locus; said second resistor network comprising a second plurality of parallel-connected second resistors; selected second resistors of said second plurality of parallel-connected resistors being independently switchingly coupled for independently selectable inclusion in a second connecting of said second signal locus with said second input locus; said gain being established by at least one of said supply circuit and said selected first resistors, and said feedback circuit and said selected second resistors.