Sensing apparatus

Abstract

An object of the present invention is to provide a sensing instrument capable to detect a substance existing in a very small quantity, such as environmental pollutants, instantly with a high degree of precision. As a specific means for solving the problem, a frequency signal from a crystal oscillator is sampled using a frequency signal from a reference clock generating part, the sampling value is outputted in a digital signal, quadrature detection is conducted with the digital signal for a frequency signal corresponding to the output signal, the rotational vector rotating at a frequency corresponding to the difference between the frequency of the frequency signal and the frequency of a sinusoidal wave used for the quadrature detection is taken out, and the variation of the frequency is detected by detecting the velocity of the rotational vector based on the respective sampling values. In addition to that, the measurement range of the variation of frequency can be widened by multiplying the above-described rotational vector by the reversely rotational vector corresponding to the velocity of the rotational vector.

Description

technical field [0001] The present invention relates to a sensing device for detecting the natural frequency of a sensor vibrator, such as a quartz vibrator, by using an adsorption layer for adsorbing a sensing object formed on the surface thereof, for example, a sensor vibrator whose natural frequency is changed by the adsorption of the sensing object The amount of change and perceive the object of perception. Background technique [0002] In order to protect the environment, it is urgent to know the concentration of various environmental pollutants in rivers and soils. Even extremely small amounts of pollutants are highly toxic to the human body. Therefore, it is desired to establish a measurement technology for trace amounts of pollutants. Recently, dioxins are attracting attention as a pollutant. As methods for measuring the dioxins, a method using a gas chromatography mass analyzer and an ELISA method (applicable to an enzyme immunoassay method) are well known. If acco...

AI Technical Summary

Problems solved by technology

[0004] However, in the technology of Patent Document 1, the clock frequency of the counter is lowered by using a frequency division circuit, so the above-mentioned difference frequency is high and the number of stages of the frequency divider circuit is large. Since the phase noise increases when the number of stages increases, the above-mentioned difference frequency does not actually increase. Too high, making it difficult to ensure high measurement accuracy

As a result, the scope of application is limited, and it is difficult to apply to situations where extremely small amounts of substances such as dioxins are required to be detected with high precision

And because of the use of counters, there are also disadvantages that require high resolution and long measurement time.

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