| 摘要 |
The proposed digital measuring converter of electrical conductance of liquid can be used in equipment for oceanographic researches and control and monitoring systems. The converter contains an oscillator, a transformer electrical conductance detector, a metering unit, and additionally, a zero signal indicator and a control pulse former. The primary winding of the transformer electrical conductance detector is connected to the output of the oscillator, and the secondary winding is connected to the input of the metering unit. The metering unit contains a matching unit, a phase changer, a synchronous detector, an integrator, and a current modulator. The current modulator contains a threshold unit, a logic control unit, an output data register, and a digital-to-analog converter. The input of the threshold unit is connected to the output of the integrator. The output of the digital-to-analog converter is used as the output of the proposed measuring converter. The reference inputs of the synchronous detector and the digital-to-analog converter are connected to the output of the oscillator. The compensating winding of the transformer electrical conductance detector is connected to the output of the digital-to-analog converter. The input of the zero signal indicator is connected to the output of the oscillator. The input of the control pulse former is connected to the output of the zero signal indicator and the corresponding input of the logic control unit. The proposed converter is distinctive by its enhanced resolution and increased speed of response.
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