CONCURRENT ERROR DETECTION IN LINEAR ANALOG AND SWITCHED-CAPACITOR STATE VARIABLE SYSTEMS USING CONT

Abstract

In this paper we study the problem of concurrent error detection in analog and switched-capacitor state variable systems. The errors can arise due to failed components (resistors, capacitors, opcrational amplifiers, etc) or simply due to line opens and shorts. A failed component is one whose value has changed due to a harsh environment (heat, etc) or due to drift or one which no longer performs its intended function (such as a shorted capacitor). The error detection is performed by a small amount of additional circuitry whose inputs are tapped directly from the outputs of all the operational amplifiers that compose the circuit on which error detection is to be performed. The sensitivity of the error detection circuitry to errors in the component values can be easily adjusted. The basic idea is to use continuous matrix chechums for error detection. This is possible because the function of an analog or switched-capacitor state variable system can be represented mathematically by a set of matrices to which checksum codes can be applied.