Hybrid integrators for analog computers

Integrators have a wide range of applications in analog signal processing, e. g. in filters, Δ∑-modulators and analog computers. With decreasing supply voltage, integrators reach saturation earlier, which reduces the dynamic range. Better noise characteristics and logarithmic signal compression can help preserve small signals. When integrators are concatenated in analog computers, for example when differential equation systems are calculated or in Δ∑-modulators, scaling is a critical issue. Therefore, methods are sought that allow an extension of the dynamic range while maintaining high linearity.With hybrid integrators, the dynamic range can be extended by a multiple of the supply voltage range. The basic principle of hybrid integrators is the digital counting of an analog range overflow. This overflow is detected with comparators before the integrator goes into saturation. There are now various ways in which the analog signal level can be reduced after the analog overflow has been digitally detected.In this paper, a new concept for a hybrid integrator is presented, which uses a continuous-time reset and still provides an exact analog and digital representation of the hybrid integral at all times. This method makes the new concept universally applicable in analog computer systems.