The book describes circuit devices and methods of analog signal processing from typical sensors of physical quantities and means for their digitization and reconstruction including description of selected methods of their digital processing. The book is supplemented with practical principles of construction of analog-digital systems in terms of the transmission and isolation of analog signals, the method of printed circuit design, the elimination of interfering signals, the method of power supply and grounding of circuits. It also contains examples of simulations of these circuits in time and frequency domain in MULTISIM program. The book is suitable for college students of technical schools and specialists in the field of design, construction, and use of measuring systems for the measuring and processing of signals from conventional sensors of physical quantities