Topic
Noise measurement
About: Noise measurement is a research topic. Over the lifetime, 19776 publications have been published within this topic receiving 308180 citations.
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TL;DR: In this article, an effective approach to attenuate random and coherent linear noise in a 3D data set from a carbonate environment is discussed, where the authors demonstrate a seismic inline section from a noisy 3D seismic cube.
Abstract: This paper discusses an effective approach to attenuate random and coherent linear noise in a 3D data set from a carbonate environment. Figure 1 illustrates a seismic inline section from a noisy 3D seismic cube. Clearly, the section in Figure 1 is corrupted by undesirable random noise and coherent noise that are linear and vertically dipping in nature
225 citations
TL;DR: The performance of the ED with estimated noise power (ENP), addressing the threshold design and giving the conditions for the existence of the SNR wall is analyzed, and analytical expressions for the design curves (SNR vs. observation time for a target performance) for the ENP-ED are derived.
Abstract: An uncertain knowledge of the noise power level can severely limit the energy detector (ED) spectrum sensing capability. In some situations this uncertainty can cause signal-to-noise ratio (SNR) penalties or even the rise of the SNR wall phenomenon. In this paper we analyze the performance of the ED with estimated noise power (ENP), addressing the threshold design and giving the conditions for the existence of the SNR wall. We derive analytical expressions for the design curves (SNR vs. observation time for a target performance) for the ENP-ED. Then we apply our analysis to cognitive radio (CR) systems where energy detection is used for fast sensing. For example it is shown that the SNR penalty with respect to ideal ED is of 5 log10(1+λ/λ) dB, when the time dedicated to noise power estimation is a multiple λ of the ED observation interval.
224 citations
07 Apr 2011
TL;DR: This paper introduces a fractional-N PLL based on a 1b TDC, achieving jitter of 560fsrms (from 3kHz to 30MHz) at 4.5mW power consumption, even in the worst-case of fractional spur falling within the PLL bandwidth.
Abstract: This paper introduces a ΔΣ fractional-N digital PLL based on a single-bit TDC. A digital-to-time converter, placed in the feedback path, cancels out the quantization noise introduced by the dithering of the frequency divider modulus and permits to achieve low noise at low power. The PLL is implemented in a standard 65-nm CMOS process. It achieves - 102-dBc/Hz phase noise at 50-kHz offset and a total absolute jitter below 560 fsrms (integrated from 3 kHz to 30 MHz), even in the worst-case of a -42-dBc in-band fractional spur. The synthesizer tuning range spans from 2.92 GHz to 4.05 GHz with 70-Hz resolution. The total power consumption is 4.5 mW, which leads to the best jitter-power trade-off obtained with a fractional-N synthesizer. The synthesizer demonstrates the capability of frequency modulation up to 1.25-Mb/s data rate.
221 citations
TL;DR: The statistical distribution of background noise was analyzed for MR acquisitions with a single-channel and a 32-channel coil, with sum-of-squares (SoS) and spatial-matched-filter (SMF) data combination, with and without parallel imaging using k-space and image-domain algorithms, with real-part and conventional magnitude reconstruction and with several reconstruction filters.
221 citations
TL;DR: An algorithm is proposed which detects speech pauses by adaptively tracking minima in a noisy signal's power envelope both for the broadband signal and for the high-pass and low-pass filtered signal in poor signal-to-noise ratios (SNRs).
Abstract: A speech pause detection algorithm is an important and sensitive part of most single-microphone noise reduction schemes for enhancement of speech signals corrupted by additive noise as an estimate of the background noise is usually determined when speech is absent. An algorithm is proposed which detects speech pauses by adaptively tracking minima in a noisy signal's power envelope both for the broadband signal and for the high-pass and low-pass filtered signal. In poor signal-to-noise ratios (SNRs), the proposed algorithm maintains a low false-alarm rate in the detection of speech pauses while the standardized algorithm of ITU G.729 shows an increasing false-alarm rate in unfavorable situations. These characteristics are found with different types of noise and indicate that the proposed algorithm is better suited to be used for noise estimation in noise reduction algorithms, as speech deterioration may thus be kept at a low level. It is shown that in connection with the Ephraim-Malah (1984) noise reduction scheme, the speech pause detection performance can even be further increased by using the noise-reduced signal instead of the noisy signal as input for the speech pause decision unit.
219 citations