International Journal of Smart Business and Technology
Volume 2, No. 1, 2017, pp 1-14
Goertzel DFT Estimation Based Reduced Noise Decoding for DTMF Automation System
The need to automate industrial, residential and commercial sectors has alleviated the need for Automation Systems, that are controlled by application specific communication technologies. The communication protocols considered for controlling loads situated remotely, range from wired to wireless standards. Implementation of various wireless technologies such as ZigBee, GSM/GPRS, Bluetooth, Wi-Fi require network establishment schemes, development of software, dedicated devices etc. Hence, their deployment becomes protracted making the system costly. This paper illustrates the implementation of a more reliable Mobile Controlled Automated System based on DTMF (Dual Tone Multiple Frequency) principle, which is highly efficient. The purpose of monitoring and controlling loads remotely by the user are accomplished by exploiting the existing PSTN infrastructure and mobile network. The connecting link which facilitates exchange of commands for control action is highly susceptible to noise. Hence, efforts are taken to reduce the effect of noise by designing the system in two decoding modes. Goertzel DFT estimation mode eliminates the error in decoding and mitigates the noise in the system, whereas DTMF decoder IC MT8870D-1 mode is dedicated only for decoding. The comprehensive analysis studying both the modes is illustrated and results are presented.