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无锡科技职业学院科技论文
The application of electronic nose
signal must be appropriate pretreatment (to eliminate noise, feature extraction, signal
amplification, etc.), using a suitable pattern recognition analysis method for
processing thereof. Theoretically, each odor will have its characteristic response
spectrum, according to its characteristic response spectrum can distinguish between
small same odor. While gas sensors constituting the array to measure the
cross-sensitivity of a variety of gases, by a suitable analytical method, the mixed gas
analysis. The electronic nose is the use of various gas sensing device has a response to
this characteristic but different from each other, with the data processing methods to
identify a variety of odor, odor quality analysis and evaluation of complex component
gases. The main mechanism of the electronic nose identify each sensor in the array
has a different sensitivity of the measured gas, e.g., high response One gas may be
generated on a sensor, while the other sensor is a low response; Similarly, the 2nd gas
generating high response of the sensor is not sensitive on the 1st gas and, ultimately,
the entire sensor array response pattern is different for different gases, it is this
difference, to enable the system to identify a gas according to the response of the
sensor pattern. Electronic nose can be summarized as follows: the sensor array - the
signal preprocessing - neural networks and a variety of algorithms - computer
identification (gas qualitative and quantitative analysis). Functionally speaking, the
gas sensor array is equivalent to the biological olfactory system in a large number of
olfactory receptor cells, neural network and the computer to recognize the biological
equivalent of the brain, the rest is the equivalent of the olfactory nerve signal
transduction system. For example, the measurement of the metal oxide semiconductor
(MOS) gas sensor in response to the schematic diagram of the voltage signal. MOS
gas sensor is usually before the test shall be heated to 2500 ℃ (or higher) in order to
work properly. After the chemical reaction occurs in the testing process, the MOS gas
sensor and the sample gas / odor, will change its own gas sensitive film conductivity
and resistance values, leading to a terminal voltage of a sampling resistor in series
thereto is changed. Due to sampling resistor is fixed, so the immediate extraction of
the end of the sampling resistor voltage signal voltage MOS gas sensor response curve.