REVERSIBLE ANALOG TO DIGITAL CONVERTER (ADC-DAC) WITH ANALOG AND DIGITAL SIGNAL PROCESSING AND ENCODING FUNCTIONS

摘要

An Operational Analog to Digital (SYMAD) Convertor cell for converting an analog signal into a discrete binary code. An analog signal is processed by sample and hold circuitry and then compared to a reference voltage by a comparator. The comparator output is the converted digital output. This output is coupled back to the control input of an analog switch which selects either the reference voltage or a predetermined potential, typically zero volts, to couple to an inverting input of an operational amplifier. The analog signal input is also coupled to the non-inverting input of the operational amplifier. The operational amplifier is configured as a differential amplifier with a gain of two. If the digital output of the comparator is a logic 1, then the operational amplifier output is two times the difference between the analog signal and the reference voltage. If the digital output of the comparator is a logic 0, then the output of the operational amplifier is two times the analog signal. As many SYMAD cells as necessary may be provided to obtain a desired resolution.