ABSTRACT
Digital-to-analog (D/A) conversion is the process of converting digital codes into a continuous range of analog signals. Analog-to-digital (A/D) conversion is the complementary process of converting a continuous range of analog signals into digital codes. D/A and A/D applications have evolved from predominately military-driven applications to consumer-oriented applications. Up to the mid-1980s, the military applications determined the design of many D/A and A/D devices. D/A and A/D conversion circuits are available as integrated circuits from many manufacturers. The resolution of a D/A circuit is the smallest change in the output analog signal. In an A/D system, the resolution is the smallest change in voltage that can be detected by the system and can produce a change in the digital code. Digital codes are typically converted to analog voltages by assigning a voltage weight to each bit in the digital code and then summing the voltage weights of the entire code.
