A signal processing system includes an analog-to-digital converter (ADC) that is used to convert a first analog value into a first digital value and convert a second analog value into a second digital value. The ADC includes a first digital-to-analog converter (DAC) circuit and a second DAC circuit operating in different voltage domains. A first bit segment and a second bit segment of each digital value are determined via the first DAC circuit and the second DAC circuit, respectively. An analog injection value is injected to the second analog value, the analog injection value is converted from a digital injection value formed by a subset of bits of the second bit segment of the first digital value, and the second bit segment of the second digital value is derived from injecting the digital injection value to a digital value determined by the second DAC circuit.