Digitally controlled amplifiers with fewer resistors and sensitivities

New digitally controlled amplifiers are proposed. They have fewer resistors and reduced sensitivities compared to Koutzarov's amplifiers.

[1]  Robert W. Brodersen,et al.  Potential of MOS Technologies for Analog Integrated Circuits , 1977, ESSCIRC '77: 3rd European Solid State Circuits Conference.

[2]  S. I. Koutzarov Simple digitally controlled amplifier , 1983 .