Monitoring circuit used for quartz crystal microbalance blood sugar monitoring system

Abstract

The invention provides a monitoring circuit used for a quartz crystal microbalance blood sugar monitoring system. The monitoring circuit comprises a simulative oscillation circuit and a digital frequency detection circuit, the simulative oscillation circuit is used for acquiring realtime resonance frequency signals of a crystal oscillation sensor and comprises a detection module, a reference module, a power source module, a difference frequency circuit and a signal amplifying unit, the digital frequency detection circuit calculates resonance frequency of the crystal oscillation sensor according to three branches of resonance frequency signals received from the simulative oscillation circuit, calculates numerical value of content of specific substance indicated by the resonance frequency according to the resonance frequency of the crystal oscillation sensor and comprises a signal adjusting and clock reference unit, a CPLD (complex programmable logic device) unit and an interface unit.

Description

technical field [0001] The invention relates to a quartz crystal microbalance blood sugar monitoring system, in particular to a monitoring circuit for the quartz crystal microbalance blood sugar monitoring system. Background technique [0002] Usually, a quartz crystal oscillator ("crystal oscillator" for short) can be used to detect the frequency signal to measure the human body's trace sign value such as blood sugar level. Generally speaking, a crystal oscillator includes an AT-cut quartz wafer and metal electrodes plated on its surface. Taking advantage of the inverse piezoelectric effect of quartz crystals, an alternating voltage can be applied to the metal electrodes of the quartz crystals to excite the quartz crystals to vibrate at the same frequency. When the frequency of the external excitation voltage is consistent with the natural oscillation frequency of the quartz crystal, resonance will occur. At this time, the amplitude is the largest and the oscillation is th...

AI Technical Summary

Problems solved by technology

However, the magneto-acoustic resonance technology has the disadvantages of low energy transmission efficiency and high power consumption. As a result, the piezoelectric material used as a sensor and the distance between the excitation coil must be very close to achieve effective excitation and detection of the signal, resulting in measurement results that are easily affected by the external environment. In addition, the detection device using the magnetic acoustic resonance technology needs to use a bulky and expensive signal generator and lock-in amplifier, which limits the popularization and use of the detection device using the magnetic acoustic resonance technology

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