A simple analogue to digital converter with non-linearity compensation

The converter combines a high-speed electromechanical switch with a transistor switching amplifier. The electromechanical switch is a motor driven uniselector and a chain of high stability resistances is connected around the two levels of the switch to form a potential divider. A signal from this potential divider is subtracted from the unknown input voltage in the range 0¿10 volts and the difference appears across the input of the switching amplifier. When balance is reached the amplifier signal reverses in sign and the switching amplifier energizes a high-speed relay to stop the motor uniselector. Balance is achieved in ¿ second and the accuracy of digitizing is 1 part in 100. The converter is extremely flexible in output coding and gives complete non-linearity compensation for any function with suitable connections on the spare levels of the motor uniselector. It is very simple and cheap to construct and can be used to digitize from the most types of potentiometric recorder.