A digital function generator capable of generating any arbitrary single valued function representable by an independent and a dependent variable is disclosed. A state signal generator produces a plurality of output state signals corresponding to quantized sequential values of the independent variable. Predetermined ones of the quantized sequential signals correspond to predetermined incremental values of the dependent variable. A decoder monitors the output of the state signal generator and provides an output signal corresponding to the time of occurrence of the predetermined quantized sequential signals and the "sense" of the dependent variable change. A monitor provides an output signal which varies as a function of the decoder output. A digital-to-analog converter converts the monitor output to an analog signal representative of the function.
The counting circuit described issues a numerical information which is a non-linear function of the number of pulses applied to its input. The circuit comprises dividers which divide by integers K.sub.i the pulses applied to their inputs. A first selector connects the output of one of the dividers to the input of a counter in response to a first signal. The content of the counter is compared with numbers k.sub.i by comparators. The output of one of the comparators is connected to a control circuit by a second selector controlled by a second signal issued by the control circuit in response to a comparison signal.
A digital function fitter includes an UP/DOWN counter, a clock pulse generator, a counter counting the number of the clock pulses, a plurality of gate circuits and a Multiplexer for supplying selectively the digital outputs of the gate circuits to the UP/DOWN counter. A non-linear digital input is applied to the up-terminal of the UP/DOWN counter and the digital outputs from the gate circuits are applied to the down-terminal of the UP/DOWN counter. A linearized digital value can be obtained from the counter when the number of the non-linear digital input coincides with the digital outputs from the gate circuits.
"PROCESS CONTROL APPARATUS" includes two transducers for measuring two parameters of the process, and a memory unit to which the outputs from the transducers are fed. The memory unit produces an output dependent on the values of the two parameters, this output being binary, and being coupled to a counter which also receives clock pulses. The counter samples the memory unit output, and produces an output pulse when the clock pulse reading is equal to the sample reading. The output pulses are then used to control the process.
An electrical waveform generator provides a memory for storing a plurality of data points representing sequential amplitude values of a desired waveform, a digital-to-analog converter for converting the data points to analog voltages for generating the desired waveform and apparatus for selectively coupling the data points to the converter, including apparatus for selecting groups of data points and for selectively looping through the groups.
