Normalized power spectrum analysis based on Linea Prediction Code (LPC) using time integral procedures

Recently malfunctions of telecommunication installations caused by switching noises of electric equipment or devices have been increasing. The switching noises usually have low frequency components less than 50Hz and also more than 9kHz or 150 kHz. It is useful to detect power spectrum of noises in order to solve EMC problems. The LPC (Linear Prediction Code) method is known as a powerful frequency estimation method. This paper proposes a new normalized power spectrum analysis technique based on LPC. Introducing time integration on a time series of the noise waves to the LPC shows that noise power spectrum (frequencies and levels) can be estimated more precisely than using the conventional LPC method. Estimated deviations of frequency and NPS (normalized power spectrum) between given frequencies and extracted frequencies of quasi signals are less than 4%, and the proposed technique can also extract low frequencies with short durations from time series of noises. Key-Words: LPC (Linear prediction code), frequency analysis, time integral, simulations and experiments WSEAS TRANSACTIONS on COMMUNICATIONS Kazuo Murakawa, Hidenori Ito, Masao Masugi, Hitoshi Kijima E-ISSN: 2224-2864 452 Volume 13, 2014