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Multiple speaker localization and tracking in noisy and reverberant environments is a challenging task. A distributed multiple speaker tracking method based on unscented particle filter and data association is proposed in microphone array networks. First, the generalized cross correlation (GCC) function is estimated at each node and the time difference of arrival (TDOA) is viewed as observation for tracking. Considering the ambiguity of the observations caused by the interference of other acoustic sources and multipath, the data association technique is used at each node to associate the available observations with each speaker. Then according to the characteristics of GCC function, the association probability of valid observations for each speaker is calculated by combining the amplitude of the valid observations with the statistical distance. After that, the local state of speakers is obtained at each node based on unscented particle filter. Finally, according to the reliability of the local state of each node, a dynamic weighted consensus fusion algorithm is presented to approximate the global state estimation and obtain good multiple speakers tracking performance. The proposed method can track multiple speakers under reverberant and noisy environments in a distributed manner and is scalable and robust against node failure in DMA. Simulation results verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

The noise contribution of a DC offset cancelation (DCOC) circuit in a programmable gain amplifier (PGA) is studied for the first time in this paper. The analysis presented shows that the DCOC-induced noise may deteriorate the PGA's noise performance significantly if we do not pay enough attention to it. For an analog DCOC (ADCOC), it is concluded that the PGA's noise increases rapidly as the output DC offset decreases, thereby causing difficulties to achieve both low noise and low DC offset simultaneously. We propose an optimization technique that can effectively alleviate the noise issue by increasing the feedback amplifier's gain and the resistor's value simultaneously, while maintaining a reasonable DC gain. For a digital DCOC (DDCOC), the extra noise comes from the transistors of the current source (sink) bank. The transistors with a longer channel length are preferred for their lower thermal and flicker noise current. The proof-of-concept prototypes are designed in a 0.18- $$\upmu $$ m CMOS process, and a 3-stage PGA with ADCOC is fabricated. The measurement results validate the analysis and simulation results well. [ABSTRACT FROM AUTHOR]