A new high-speed general purpose I/O with real-time computing capability

Abstract

Real-time data acquisition and control systems incorporating a general purpose digital computer (GPC) are considered for convenience to be composed of three parts: transducers and transmission paths, an input-output mechanism (I/O), and the GPC. The transducers and transmission paths considered in particular are those resulting in the desired data being phase-modulated on carrier waveforms. This type of phase-encoded information may be received from a variety of sources, among which are shaft-angle resolvers with sine-cosine excitations, and Doppler navigation systems. The primary focus of attention in this paper is a new I/O which can receive the phase-modulated waveforms directly, perform a variety of processing functions on the raw data in its phase-modulated form, and present the processed data in a convenient binary format to the GPC. The new I/O can process data from a number of sources in parallel at relatively high speeds, thereby leaving the GPC time for monitoring, adaptive parameter adjustment, and other sophisticated decision and control functions. Similar techniques utilizing different phases of the computer clock signal permit the GPC to generate digital and/or analog commands to transducers via the I/O.