Abstract: A gas measurement and analysis system having a gas chromatograph which converts a gas mixture from a source to a time varying continuous signal. This signal is sampled and converted to digital form by an analog to digital converter which provides a stream of amplitude dependent digital values at equally spaced time intervals. These sampled signals are applied to a rate of change estimator system which provides an accurate estimate of the time derivative of the sampled signal by means of recursive digital feedback. The output of the estimator system is applied to a processor.

Abstract: A system for measuring on-line the energy content and flow of a gas mixture within a pipeline. The system includes a gas chromatograph for producing a time varying signal related to the component composition of the gas mixture. The pressure and temperature of the gas mixture is measured and these signals as well as the time varying signal from the chromatograph are converted to digital form. These signals are applied to control means which produces energy and flow rate signals of the gas mixture in the pipeline based on the on-line pressure, temperature and component composition. These signals are corrected by supercompressibility factor signals as a function of component composition.

Abstract: A system for testing open thermocouples in a data acquisition system in which each of a plurality of thermocouples is sequentially read. Each thermocouple has an associated filter capacitor and resistance network and each has a different common-mode voltage with respect to a reference potential. Charging means is effective to charge each filter capacitor in sequence after a reading has been taken. For a normal thermocouple, the filter capacitor discharges through the associated resistance and thermocouple prior to the next sequential reading of that thermocouple. For an open thermocouple the filter capacitor remains charged indicating that the thermocouple is open at the time of the next sequential reading of that thermocouple.

Abstract: A gas measurement and analysis system having a gas chromatograph which converts a gas mixture from a source to a time varying continuous signal. This signal is sampled and converted to digital form by an analog to digital converter which provides a stream of amplitude dependent digital values at equally spaced time intervals. These sampled signals are applied to a rate of change estimator system which provides an accurate estimate of the time derivative of the sampled signal by means of recursive digital feedback. The output of the estimator system is applied to a processor.

Abstract: A multi-user, multi-task analog/hybrid system having a digital computer and a main digital memory. The programs are run with one of the analog and digital programs becoming time critical. A linkage system having ADC and DAM channels link the data flow between the analog computers and the digital computer. The linking system is controlled to substantially allocate all of the data flow to the time critical analog and digital programs and as available data flow is allocated to nontime critical programs. After allocation, there is automatic data transfer without digital computer intervention.

Abstract: A variable analog function generator which is independent of an external computer during the time that it generates at least one predetermined output function of at least one input variable. The output function is expressed in terms of hybrid variables each having an analog portion and a digital portion. The function generator has a first dedicated memory which is loaded during set up time with data related to breakpoints defining the input variable. A second dedicated memory is loaded during set up time with tables of values defining the digital portion. During function generation, the analog portions are generated in response to (1) the input variable and (2) the data related to the breakpoints which is accessed in parallel from the first dedicated memory. The output function is generated in response to (1) the analog portions and (2) the tables of values accessed from the second dedicated memory.

Abstract: An analog switching system having fan-out for switching a plurality of inputs coupled to analog signal sources with respect to a plurality of outputs coupled to analog signal destinations. A three stage switch matrix includes input, middle and output switch blocks with each block having a plurality of analog switch means and latching means. Any one input terminal of a switch block may be connected to any one or more of the output terminals of that block. A matrix controller coupled to each of the switch blocks addresses each switch block and actuates at least one of the latching means to provide a connection assignment for at least one of the analog switching means.