Programmable wide range voltage adder/subtractor and its application as an encoder

A new programmable wide range voltage adder/subtractor and its application as a new encoder are presented. The programmable proposed adder/subtractor is based on current conveyor analogue switches. The proposed adder/subtractor yields advantages over previous adders and subtractors in view of the wide operation range covering both positive and negative values and its function to be programmable by digital codes. An example application of the proposed adder/subtractor as an encoder is described. The highlight of the proposed encoder is the programmable encoding, which is gained from the proposed adder/subtractor. The 0.5 /spl mu/m/level 49 MOS model of AMI obtained through MOSIS is chosen. Simulation results using parameters extracted from the layout (including parasitic capacitance) are obtained. Results show that the operation range of the proposed adder/subtractor is between -600 mV and 600 mV with a supply voltage of /spl plusmn/2 V, the harmonic distortion is lower than 1% in the operation range, and the operation frequency is up to 100 MHz. The result of the encoder is also shown to confirm an operation that corresponds to the theory.