Abstract: There is provided a digitally controlled first order hold circuit and waveform synthesizer for digitally controlling the representation of a function over an approximation interval. In accordance with the operation of the invention, the first order hold circuit and waveform generator receives a digital data input signal which contains initial condition data, up/down data, and slope data for the approximation interval. The initial condition data is loaded into an up/down counter which is incremented using counting data at a rate depending on the value of the slope data and in a direction depending on the value of the up-down data. In order to minimize delays arising from data acquistion, two frequency synthesizer circuits are provided such that one frequency synthesizer provides counting data while the other frequency synthesizer receives slope data. During alternating intervals, the other frequency synthesizer circuit provides counting data while the other circuit receives slope data.

Abstract: Utility or industrial meters having rotating elements are monitored by an automatic reading unit through which digital input data is stored and read out in response to interrogation by a coded polling signal transmitted to the unit through telephone lines. Readout occurs during a transmit cycle and includes the serial transfer of stored digital data to digital synthesizers through which data is converted to a sinusoidal analog signal transmitted by the telephone lines for decoding at a data collecting station. By the addition of optional components, time of day metering, demand metering and the exercise of control functions at a remote site may be effected.