DIGITAL FREQUENCY METER (DFM) BASED DATA ACQUISITION SYSTEM FOR ARTIFICIAL NOSE

摘要

This paper presents a FPGA based Digital Frequency Meter as Data acquisition system, implemented on the Xilinx Family-XC4003E for Artificial Nose. The odor is input using a 3-element Sn0{sub}2 sensor array. The sensor output voltage is converted to frequency with the help of voltage to frequency converter. This frequency is forwarded in a multiplexed way to the DFM for measurement. A RAM for logging the acquired data is also implemented. The major advantage of using this DFM based data acquisition system is that there is no need of analog to digital converter or the related circuitry. The odor output of methanol and ethanol was measured. The collected data was used for training Back Propagation Artificial Neural Network for odor identification. The experiments showed promising results. The paper details the design of DFM as data acquisition system and the experiments carried out to test the system performance. The specifications of the system along with preliminary results are also discussed.