INPROX Sensors, Boston, MA, offers its inGen Linear Direct digital sensors that can interface directly with microprocessors without the need for signal conditioning, and use a specially tuned oscillator that produces a frequency of oscillation, a square wave output that is read as a pulse train by microprocessors. Because of the sensors' operating principle, they can perform multifunction sensing, e.g., an InGen position sensor provides a position status update at 25 kHz to 500 kHz. First-, second-, and third-order derivatives of the position information allow you to measure position, acceleration, velocity, and jerk with a single measurement. Different physical quantities can use different bands of working frequencies, creating multiple distributed sensors on a single bus.