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: A transition-controllable noise source is developed in a 0.1-/spl mu/m P-substrate N-well CMOS technology that can generate substrate noises with controlled transitions in size, interstage delay and direction for experimental studies on substrate noise properties in a mixed-signal integrated circuit environment.
Abstract: A transition-controllable noise source is developed in a 0.1-/spl mu/m P-substrate N-well CMOS technology. This noise source can generate substrate noises with controlled transitions in size, interstage delay and direction for experimental studies on substrate noise properties in a mixed-signal integrated circuit environment. Substrate noise measurements of 100 ps, 100-/spl mu/s resolution are performed by indirect sensing that uses the threshold voltage shift in a latch comparator and by direct probing that uses a PMOS source follower. Measured waveforms indicate that peaks reflecting logic transition frequencies have a time constant that is more than ten times larger than the switching time. Analyses with equivalent circuits confirm that charge transfer between the entire parasitic capacitance in digital circuits and an external supply through parasitic impedance to supply/return paths dominates the process, and the resultant return bounce appears as the substrate noise.
77 citations
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TL;DR: This work explains the circuit theory, paying particular attention to the measurement bandwidth, the causes of noise and drift, and the proper selection of circuit components for optical radiation detectors that may replace photomultiplier tubes that have been used traditionally and or that were too costly to be used.
Abstract: Recent improvements in commercial silicon photodiodes and operational amplifiers permit electrical noise to be reduced to an equivalent of 0.1 fA of photocurrent when a measurement time of 400 s is used. This is equivalent to a photocurrent resulting from fewer than 800 photons/s, and it implies a dynamic range of 14 orders of magnitude for a detector circuit. We explain the circuit theory, paying particular attention to the measurement bandwidth, the causes of noise and drift, and the proper selection of circuit components. These optical radiation detectors complement the primary radiometric standards. These detectors may replace photomultiplier tubes that have been used traditionally and or that were too costly to be used.
76 citations
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TL;DR: In this article, the authors proposed a high speech quality noise suppression method based on weighted noise estimation and MMSE STSA, which continuously updates the noise estimate, using weighted noisy speech according to the estimated speech-to-noise ratio.
Abstract: This paper proposes a high speech quality noise suppression method based on weighted noise estimation and MMSE STSA. The proposed method continuously updates the noise estimate, using weighted noisy speech according to the estimated speech-to-noise ratio. In order to fully utilize the improvement offered by noise estimation, the spectral gain is corrected according to the estimated speech-to-noise ratio. By using accurate noise estimation, more accurate SNR than in the conventional method is obtained, which helps to reduce distortion in the enhanced speech. In subjective speech quality evaluations, the five-stage MOS was improved by 0.35 and 0.40 at the maximum, respectively, for the cases in which the speech was encoded and was not encoded after noise suppression. The improved version, which was developed on the basis of the proposed noise suppressor, satisfies all 3GPP minimum requirements for speech quality and has been installed in a commercially available model. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 89(2): 43–53, 2006; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjc.20145
76 citations
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TL;DR: A new model for the signal dependent transition noise and partial erasure which occur in the readback signal from thin film recording media is reviewed, which has its basis in physics and can be entirely specified by three parameters of the media.
Abstract: A new model for the signal dependent transition noise and partial erasure which occur in the readback signal from thin film recording media is reviewed. This model, which is referred to as the microtrack model, has its basis in physics and can be entirely specified by three parameters of the media. It is used both as a simulation tool and for analytical calculation. Through simulation, the effect of various amounts of media noise on a PR4 channel is shown. Analytically, the amount of jitter and widening effects of the noise produced by the model are examined. Also, the autocorrelation of this noise and the effect of partial erasure on it is examined.
76 citations
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07 Apr 1986TL;DR: The proposed method is a variation on this scheme wherein the system is probed twice using sequences chosen from among the Golay codes, which have the remarkable property that their autocorrelation functions have complementary side-lobes.
Abstract: This paper describes a digital processing technique for measuring the impulse response of a system. The method utilizes "complementary" codes as described by Golay in 1961 and has been employed by designers of radar, communications and other equipment. This paper discusses the implementation of the technique in a device that measures the impulse response of audio bandwidth systems. The paper begins by describing the general problem of impulse response measurement using digital methods. This leads to a "unit pulse" response sequence that completely characterizes a bandlimited, linear and time-invariant system. Next, Schroeder's (1979) method of probing the system with pseudo-random noise and correlating the result to obtain an estimate of this response is discussed. Our method is a variation on this scheme wherein the system is probed twice using sequences chosen from among the Golay codes. These codes have the remarkable property that their autocorrelation functions have complementary side-lobes. Finally, the response of a speaker/microphone pair is measured using the proposed method.
76 citations