Analog signal is a continuous signal which represents physical measurements. They are generally denoted by sine waves and uses a continuous range of values to represent information.Digital signal is discrete time signals generated by digital modulation. They are generally denoted by square waves and uses discrete or discontinuous values to represent information
The process of converting discrete time digital signal into the continuous analog signal is called Digital to analog conversion(DAC). The device used for this process are called Digital to analog converters. Weighted Resistors Network(WRN) DAC and R-2R Ladder Network are the basic types of Digital to analog converters.
The process of converting continuous analog signal into discrete time digital signal is called Analog to Digital Conversion(ADC) and the device used for this process is called Analog to Digital Converters. Basically, there are 4 types of ADC converters viz-Successive approximation ADC,Ramp ADC,Dual Ramp ADC and Flash ADC.