Measuring device and measuring method for continuous physical quantity

Abstract

The invention discloses a measuring device and a measuring method for continuous physical quantity. The measuring device comprises a timing unit, a sampling unit, a judgment unit, a calculating unit and an output unit, wherein the timing unit is used for outputting a time base and a time scale; the sampling unit samples the continuous physical quantity at time intervals of satisfying the Nyquist sampling theorem under the control of the time base and outputs a sampling value; the judgment unit judges whether the sampling value turns or gets off a steady state process; the calculating unit calculates a steady state value for the sampling value of the sampling unit in the steady state process; and the output unit outputs the start time and the end time of the steady state process and the steady state value according to the judgment result and the time scale. The device and the method can reduce the output data quantity and do not produce aliasing simultaneously.

Description

technical field [0001] The present invention relates to the measurement and recording technology of continuous physical quantities, especially to the digital measurement and recording of temperature, pressure, flow, voltage, current, power, phase angle, etc. in thermal engineering and power systems. Background technique [0002] The value of a continuous physical quantity remains basically unchanged or does not change much for a long period of time, which is called a steady-state process; a short-term transition between two steady-state processes is called a transient process. For the sampling of process physical quantities composed of steady-state process and transient process, according to the Nyquist (also known as Shannon) sampling theorem, the sampling interval should be smaller than the minimum time constant τ of the transient process min half of. Acquiring data at such a sampling interval will generate a large amount of recorded data. In the case of telemetry, it ta...

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Problems solved by technology

Obviously, T does not satisfy the sampling theorem, which will inevitably cause aliasing, so that the recorded or transmitted data cannot correctly reflect the state and changes of the physical process, and the data is wrong and cannot be used.

[0004] If the measured average value in the T time period is used

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