Commercially available active noise control headphones rely on fixed analog controllers to drive "anti-noise" loudspeakers. Our design uses an adaptive controller to optimally cancel unwanted acoustic noise. This headphone would be particularly useful for workers who operate or work near heavy machinery and engines because the noise is selectively eliminated. Desired sounds, such as speech and warning signals, are left to be heard clearly. The adaptive control algorithm is implemented on a Texas Instruments (TI™ ) 1 TMS320C30GEL digital signal processor (DSP), which drives a Sony CD550 headphone/microphone system. Our experiments indicate that adaptive noise control results in a dramatic improvement in performance over fixed noise control. This improvement is due to the availability of high-performance programmable DSPs and the self-optimizing and tracking capabilities of the adaptive controller in response to the surrounding noise.
標簽： Commercially controllers headphones available
上傳時間： 2013-12-04
上傳用戶：dyctj
These Fourier routines were originally based on the Fourier routines of the same names from the NETLIB bihar and fftpack fortran libraries developed by Paul N. Swarztrauber at the National Center for Atmospheric Research in Boulder, CO USA. They have been reimplemented in C and optimized in a few ways for OggSquish.
標簽： routines Fourier the originally
上傳時間： 2017-09-12
上傳用戶：小眼睛LSL
We introduce a sub-cell WENO reconstruction method to evaluate spatial derivatives in the high-order ADER scheme. The basic idea in our reconstruction is to use only r stencils to reconstruct the point-wise values of solutions and spatial derivatives for the 2r-1 th order ADER scheme in one dimension, while in two dimensions, the dimension-by-dimension sub-cell reconstruction approach for spatial derivatives is employed. Compared with the original ADER scheme of Toro and Titarev (2002) [2] that uses the direct derivatives of reconstructed polynomials for solutions to evaluate spatial derivatives, our method not only reduces greatly the computational costs of the ADER scheme on a given mesh, but also avoids possible numerical oscillations near discontinuities, as demonstrated by a number of one- and two-dimensional numerical tests. All these tests show that the 5th-order ADER scheme based on our sub-cell reconstruction method achieves the desired accuracy, and is essentially non-oscillatory and computationally cheaper for problems with discontinuities.
標簽： 高精度格式
上傳時間： 2016-01-13
上傳用戶：ccsdcczd
3 Dimensions TV (3DTV) became commercially available in the United States in 2010 and service in other countries was expected to follow soon thereafter. 3DTV is a subset of a larger discipline known as 3D Video (3DV). There are now many routine vendor announcements related to 3DTV/3DV, and there are also conferences wholly dedicated to the topic.
標簽： Transmission Encoding Content Capture 3DTV and
上傳時間： 2020-05-23
上傳用戶：shancjb
Since the telephone was invented in the late nineteenth century, there has been a steady development of telephone services, and the number of subscribers has con- tinuously increased. One of the most revolutionary developments in telephone serv- ice in the late twentieth century was the introduction of the cellular variety of mobile phone services.
標簽： Engineering Capacity Systems CDMA
上傳時間： 2020-05-26
上傳用戶：shancjb
Regardless of the branch of science or engineering, theoreticians have always been enamored with the notion of expressing their results in the form of closed-form expressions. Quite often, the elegance of the closed-form solution is overshadowed by the complexity of its form and the difficulty in evaluating it numerically. In such instances, one becomes motivated to search instead for a solution that is simple in form and simple to evaluate.
標簽： Communication Channels Digital Fading over 1st
上傳時間： 2020-05-27
上傳用戶：shancjb
Regardless of the branch of science or engineering, theoreticians have always been enamored with the notion of expressing their results in the form of closed-form expressions. Quite often the elegance of the closed-form solution is overshadowed by the complexity of its form and the difficulty in evaluating it numerically. In such instances, one becomes motivated to search instead for a solution that is simple in form and likewise simple to evaluate.
標簽： Communication Channels Digital Fading over 2nd
上傳時間： 2020-05-27
上傳用戶：shancjb
When joining Siemens in 2001, I also extended my research interest towards radio net- work planning methodologies. This area of research brought together my personal interest in mobile communications and in the design of efficient algorithms and data structures. Between 2001 and 2003, I participated in the EU project Momentum, which was target- ing the performance evaluation and optimization of UMTS radio networks. I
標簽： Efficient Methods WCDMA for
上傳時間： 2020-05-27
上傳用戶：shancjb
The first Third Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) networks were launched during 2002. By the end of 2005 there were 100 open WCDMA networks and a total of over 150 operators having frequency licenses for WCDMA operation. Currently, the WCDMA networks are deployedinUniversalMobileTelecommunicationsSystem(UMTS)bandaround2GHz in Europe and Asia including Japan and Korea. WCDMA in America is deployed in the existing 850 and 1900 spectrum allocations while the new 3G band at 1700/2100 is expected to be available in the near future. 3GPP has defined the WCDMA operation also for several additional bands, which are expected to be taken into use during the coming years.
標簽： HSDPAHSUPA Access Speed Radio UMTS High for
上傳時間： 2020-05-27
上傳用戶：shancjb
In this paper we revisit hybrid analog-digital precoding systems with emphasis on their modelling and radio-frequency (RF) losses, to realistically evaluate their benefits in 5G system implementations. For this, we decompose the analog beamforming networks (ABFN) as a bank of commonly used RF components and formulate realistic model constraints based on their S-parameters. Specifically, we concentrate on fully-connected ABFN (FC-ABFN) and Butler networks for implementing the discrete Fourier transform (DFT) in the RF domain. The results presented in this paper reveal that the performance and energy efficiency of hybrid precoding systems are severely affected, once practical factors are considered in the overall design. In this context, we also show that Butler RF networks are capable of providing better performances than FC-ABFN for systems with a large number of RF chains.
標簽： Analog-Digital Precoding Hybrid
上傳時間： 2020-05-27
上傳用戶：shancjb
