Abstract: A development system providing a property-method-event programming (PME) model for developing context-free reusable software components is described. Despite the absence of any C++ language support for events, the present invention provides a type-safe "wiring" mechanism--one using standard C++ to dispatch an event, raised by one object (the "event source"), to a method of another object (the "event sink"), with the requirement that the event source does not need to know the class of the event sink. As a result, the system allows developers to create C++ software components which can be connected together without the components having to know anything about the makeup of the component to which it is connected. Thus, developers can create pre-packaged, re-usable software components which can simply be "plugged into" a design--all accomplished within the confines of the standard C++ programming language (i.e., without having to employ proprietary extensions).

Abstract: An analog-to-digital converter of the ramp-integrator type utilizing a special technique to reduce errors due to offset voltages. In a pre-conversion cycle, the integrator first is ramped away from a datum level and then back to that level, by sequential application of opposite-polarity reference signals. A digital net offset error is thereby determined as the difference in clock time between (a) the total time of ramp-up-and-back and (b) a fixed time period set by a clock generator. During the subsequent conversion cycle, the integrator is ramped up by the unknown analog signal and then is ramped back by a reference signal. The time of ramp-up is controlled in accordance with the amount of previously-determined net offset error so as to provide error correction.In the embodiment disclosed, the ramp-up time during the pre-conversion cycle is set at k/2 clock pulses, and the digital offset error is the difference in clock pulse time between the return to datum level and a fixed time of k clock pulses.

Abstract: An analog-to-digital converter of the ramp-integrator type utilizing a special technique to reduce errors due to offset voltages. The integrator first is ramped up and then back to a reference level, by sequential application of opposite-polarity reference signals. A digital determination of net offset error then is made by comparing the total time of ramp-up-and-back with a fixed time period set by a clock generator. During the subsequent conversion operation, integration of the analog signal is controlled in accordance with the amount of net offset error so as to provide a feed-forward error correction. Integration is always in the same direction away from zero for analog signals of either polarity, thus avoiding the effects of discontinuity around zero input.