Noise measurement

About: Noise measurement is a research topic. Over the lifetime, 19776 publications have been published within this topic receiving 308180 citations.

The effects of phase noise in COFDM

Abstract: It is shown that the amounts of these effects can be deduced from the spectrum of the phase noise using a pair of weighting functions. Use of these weighting functions simplifies the process of computation; it also makes it easier to visualize the consequences of any modifications to the phase-noise spectrum. Some illustrations are given of the two phase-noise effects on the constellation of a DVB-T digital television signal, along with some practical observations on receiver implementation.

Theoretical noise reduction limits of the generalized sidelobe canceller (GSC) for speech enhancement

Abstract: We present an analysis of the generalized sidelobe canceller (GSC). It can be shown that the theoretical limits of the noise reduction performance depend only on the auto- and cross-spectral densities of the input signals. Furthermore, we compute the limits of the noise reduction performance for the theoretically determined diffuse noise field, which is an approximation for reverberant rooms. Our results show that the GSC cannot reduce noise further than 1 dB. These results were verified by simulation of reverberant environments. Only in sound-proof rooms with a reverberation time less than 100 ms the GSC performs well.

Voice activity detection for cellular networks

Abstract: Algorithms for voice activity detection in the presence of vehicular noise and babble noise are presented. The voice activity detector (VAD) designed for vehicular noise is an improvement upon the VAD adopted for the discontinuous transmission (DTX) mode of the GSM standard, and performs significantly better at low SNR levels. Work on a VAD that is suited for the babble noise environment is also briefly mentioned, and a scheme for combining the two VADs is proposed.

Derivative-Free Kalman Filtering Based Approaches to Dynamic State Estimation for Power Systems With Unknown Inputs

Abstract: This paper proposes a decentralized derivative-free dynamic state estimation method in the context of a power system with unknown inputs, to address cases when system linearization is cumbersome or impossible. The suggested algorithm tackles situations when several inputs, such as the excitation voltage, are characterized by uncertainty in terms of their status. The technique engages one generation unit only and its associated measurements, and it remains totally independent of other system wide measurements and parameters, facilitating in this way the applicability of this process on a decentralized basis. The robustness of the method is validated against different contingencies. The impact of parameter errors, process, and measurement noise on the unknown input estimation performance is discussed. This understanding is further supported through detailed studies in a realistic power system model.

Characterization, evaluation, and design of noise Separator for conducted EMI noise diagnosis

Abstract: In this paper, at first, three requirements for noise separators are specified and the disadvantages of traditional evaluation methods are pointed out. Noise separators are then characterized using scattering parameters (S-parameters). Existing noise separators are evaluated according to the specified requirements. Finally a noise separator is proposed with parasitic controlled design and the prototype is evaluated using the proposed method. An electromagnetic interference (EMI) measurement shows that the proposed noise separator can effectively separate noise and that it is easy to use.