Working with signals in the digital domain requires sampling the analog signal at regular intervals. The sampling operation can also produce a noise which cannot be distinguished from the real signal due to the aliasing effect.
One of the most talented and interesting authors on Planet Analog and EDN is Dennis Feucht, who has written numerous popular articles and blogs.
One of the strategic design considerations for integration of microcomputers into measurement instruments is how to relate the electronic circuits of the instrument to the microcomputer and user interface.
The NASA Orion Spacecraft will have a strong fiber optic emphasis for its on-board data network. A Time-Triggered Ethernet distribution network is critical here.
The most common method of measuring current is low-side sensing. A sense element or shunt resistor is placed in series with the load between the load and ground.