Balanced bridge

Abstract

A balanced bridge comprises an input signal source, a reference impedance, an impedance to be tested, a bridge balancing module and a balance control module. The reference impedance is serially connected with the impedance to be tested and connected with the input signal source and is used for obtaining current vectors. The bridge balancing module comprises a reference impedance current extraction unit and an impedance to be tested current extraction unit and is used for providing bridge output pressure for the balance control module. The reference impedance current extraction unit is coupled to two ends of the reference impedance, the impedance to be tested current extraction unit is coupled to two ends of the impedance to be tested, and an output port of the bridge balancing module is an output port of bridge output pressure. The balance control module comprises a pressure detection module, a feedback circuit module and a single chip microcomputer, wherein one end of the pressure detection module is connected with the output port of bridge output pressure, the other end of the pressure detection module is connected with the single chip microcomputer, the other end of the single chip microcomputer is connected with the feedback circuit module, and the feedback circuit module is coupled to the impedance to be tested current extraction unit.

Description

technical field [0001] The invention relates to the technical field of electrical engineering, in particular to an analog-digital hybrid balance bridge. Background technique [0002] Impedance measurement is used in laboratory and industrial production, but the implementation of impedance measurement method is more complicated, especially the impedance at small phase and high frequency, which is particularly difficult to measure. [0003] The existing impedance measurement technology is an analog type automatic balancing bridge or a full digital sampling type. The analog automatic balance bridge realizes the balance of the bridge in the form of an analog circuit, including homodyne voltage demodulation, integration, feedback, balance and other links. When the bridge is unbalanced, the unbalanced voltage is demodulated by the in-phase and quadrature phase voltages and then integrated to obtain the balance difference between the in-phase and quadrature phase voltages. The dif...

AI Technical Summary

Problems solved by technology

The analog balance bridge has a wide measurement range and high precision, but is slow in speed, difficult to realize, complex in technology, and high in product cost. It is generally a large-scale general-purpose expensive instrument

[0004] The all-digital impedance measuring instrument uses a high-speed analog-to-digital converter to perform digital operations after sampling, compares the voltage amplitude ratio and phase difference between the measured impedance and the reference impedance, and calculates the measured impedance, which is easy to implement and low in cost. The advantage of fast speed, its disadvantage is that the value range of the measurement sample and the measurement frequency range are relatively limited

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