Research Of Signal Generator For Standard Device On Multi-parameter Electrical Measuring Instruments

The multi-parameter electrical measuring instruments have widely applied in the electric power industry, testing agencies at all national levels, chemical industry, petroleum, railway and other large mining enterprises, scientific research institutions, etc. With respect to the rapidly development of application on these devices, the standardized research on measurement traceability is lagged behind hugely, which makes it particularly urgent for establish a unified set of standardized calibration method and standard device for multi-parameter electrical measuring instrument. The sine wave signal generator in standard device on multi-parameter electrical measuring instruments is an integral part of internal high precision AC power. According to the indicators of standard device, it requires the sine wave signal generator can digitally control on the output signal’s frequency and amplitude.Firstly, the paper gives a introduction of the research status at home and aborad on standard device on multi-parametric electrical measuring instruments and the research significance, then introduces the calibration method of multi-parameter electrical measuring instrument which the study based on as well as the overall technical indicators. The hardware and software design scheme of standard device is given out, in which, the hardware design is constituted by systematic components and every modules’ implementation, the software design analyses implementation processes and ideas.Secondly, the paper elaborates the design principles of the sine wave signal generator based on direct digital frequency synthesis technology. The mathematical model of the sine wave signal generator is established in which waveform synthesis and waveform processing are described. Under the guidance of this mathematical model, the circuit’s hardware implementation of signal generator are sub-module designed, software codes that generates sine wave signal are debugged by using the C language, the frequency and amplitude characteristics of the output waveform are tested and analyzed too.Finally, the system testing and error analysis on entire standard device verify the reasonableness of design scheme, achieving the desired design indexes.