VLSI Architecture for Zero Frequency Filter

Abstract

Now a days everyone is using mobile phones. Mobile phones play an important role in communication. While using mobile phones, people face the problem of noise signals. These noise signals are affecting the quality of speech signals. These noise signals maybe produced from the materials or sources such as echoes, crowded places, etc. For example, when we speak over the mobile phone or in any crowded place, the external noise adds up like the noise of the subway, train, car, etc. In real time to remove external noise is a very crucial task. A lot of research has been done in cancelling the background noise reduction. Acoustic noise is a type of noise which can produce unwanted sound and it can be reduced by selecting a higher switching frequency (at the cost of higher inverter losses). So a new technique was introduced called passive noise cancellation that supresses higher frequency acoustic noise. In order to supress the lower frequency, the passive techniques require materials that is too bulky and heavy. For these materials, an alternative method is required known as active noise cancellation. This technique does not come without its change as it is used to actively cancel the noise of the world around you to make your audio come clearer. Active noise cancellation separates noise signal and the speech signal is chosen. In order to use active noise cancellation, we use zero frequency filter technique for the cancellation of noisy speech signals. It is used for detecting the regions of glottal activity and in estimating the strength of excitation n each glottal cycle. The main advantage of active noise cancellation is to cancel the random sounds due to repetition in the waveform. ANC is used in the reduction by using a power source. It is best suited for low frequencies. VLSI architecture for zero frequency filter can be used as a voice processor in mobile applications. The existing system has produced a time delay of 220ps. In this paper, we are reducing the time delay into 120ps by using tanner tool software.