Principle of digital display instrument is introduced1

Digital display instrument is generally by the analog-to-digital conversion, nonlinear compensation and the scale of transformation has flexibility, high sensitivity, good stability, long service life, etc. Users in the use of digital display instrument for is need to master the principle of the digital display instrument, the project is to introduce the principle of digital display instrument.

digital display instrument is based on signal input, with digital display is measured directly. Key is to realize digital display through the AD conversion device change continuous variation of analog quantity to digital quantity of intermittent. In production requirements display instrument reflects the value is a function of measured parameters, and can automatically compensate other interference factors, some of these function relationship is linear, but most is nonlinear. To the measured parameters can be displayed in the form of absolute value, for display instrument, the measured parameters need to be some necessary operation, processing, and the nonlinear compensation, at the same time, the influence of other parameters to be measured. In the AD conversion, adoption of a certain unit of measurement make the continuous analog of the whole quantitative change, get the approximate staccato digital quantity.

the smaller units and the smaller the quantization error, the frequency response of the AD conversion device, such as the stability of the preamplifier and the higher, the digital quantity is more close to the value of the quantity itself recurrently. This process is through the double integral type, voltage frequency conversion, pulse width modulation and successive voltage feedback encoding type AD converter. Nonlinear compensation or scale transform is the signal of the examination to make the necessary calculations, the digital display instrument to direct digital expression of measured parameters.

analog nonlinear compensation through changing the magnification of operational amplifier to compensate for different range of input voltage, and the digital nonlinear compensation is first measured parameters of analog after AD conversion to digital quantity again into the nonlinear compensation link, has the advantages of high precision and strong versatility, along with the development of the electronic digital computer, scale transform and the nonlinear compensation by the computer to complete the task.

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