【正文】 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. 圖1Features:Electronic nose response time, speed detection, unlike other instruments, such as the gas chromatography sensors, highperformance liquid chromatography sensor need plex pretreatment process。畢業(yè)設(shè)計（論文）報告題 目 基于單片機(jī)的 電子換號牌的設(shè)計 系 別 專 業(yè) 班 級 學(xué)生姓名 學(xué) 號 指導(dǎo)教師 2013年 4 月25無錫科技職業(yè)學(xué)院科技論文 The application of electronic noseThe application of electronic noseAbstract: positive human olfactory organ is a plex physiological reaction. Nature kind of odor tens of thousands, even professionals specializing in odor identification work is often recognition errors.Keywords: electronic nose puter technology developed olfactory organs physiological reaction Customs security monitoring neural networks odor sensor identification infrared sensorIntroduction: The electronic nose developed a hightech products is simulated animal olfactory organ, scientists are still not all clear principle of the animal39。s sense of smell. However, with the development of science and technology, more authoritative some universities in the world have developed electronic nose has a wide range of applications, most notably to the number of the University of Hamburg, Germany, has absolute authority in the sensor field in the world today. Electronic nose is the response pattern to identify the odor of the gas sensor array electronic systems, it can be in a few hours, days or even a few months time within a continuous, realtime monitoring of the specific location of the odor condition. Identifying odor main mechanism of the electronic nose is that each sensor in the array has a different sensitivity of the measured gas. The core of the device of the electronic nose gas sensor. Gas sensors based on the principle of different type of metal oxide, electrochemical, and conductive polymer type, quality, photoionization type can be divided into many types. Currently the most widely used is a metal oxide.How it works: Electronic nose is mainly posed of three parts of a gas sensor array, signal preprocessing and pattern recognition. Presented in front of an active material of the sensor, an odor sensor chemical input is converted into an electrical signal by a plurality of sensor response to an odor they constitute the sensor array to the odor of the response spectrum. Obviously, the various chemical ponents in the odor sensitive materials play a role in this response spectrum for a broad spectrum of odor response spectrum. To achieve the odor qualitative or quantitative analysis, the sensor 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 crosssensitivity 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 plex ponent gases. The main mechanism of the electronic nose identify each sensor in the array has a different sensitivity of the measured gas, ., high response One gas may be generated on a sensor, while the other sensor is a low response。 measuring a wide range of assessment, it can detect a variety of different types of food。 can detect some of the human nose can not detect the gas, such as poison gas or some irritant gases, which in many areas, especially in the food industry plays an increasingly important role. And graphical cognitive equipment to help its specificity greatly enhance the development of sensor materials also contributed to the improvement of its repetitive, and with the improvement of biochips, biotechnology development and integration technology, and some nanomaterials The application of electronic nose will have broad application prospects. Many different types of the electronic nose, the typical working program that is: 1) Sensor initialization: using a vacuum pump to the air sampling lessons to small containers fitted with the electronic sensor array chamber。 3) cleaning the sensor: measured after the sample is finished, use of alcohol vapor flush . The sensor surface of the active material, the odor removal measured Bi mixture. In enter new measurement prior to the next round, the sensor still implement initialization (that is, between the work again, each sensor are required dry air or some other reference gas cleaning to meet the benchmarks). The measured odor effect of time is called the response time and the purge process and the reference gas role of the sensor array used in the initialization process time is called the recovery time.The electronic nose system consists of two parts: information acquisition the terminal (Acquisition terminal) and information processing terminal (processing terminal). 1) collection terminal is responsible for collecting the signal voltage of the MOS gas sensor array processing termina