ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Most modern digital filtering is done by taking the average (mean) of a signal or some weighted average. Another method is to use feedback, which more closely resembles how analog filters with feedback operate. In the case of low pass filters, all these methods tend to give a trade off in getting the signal to pass while attenuating the higher frequency noise. An alternative is to use a median filter, which selects the mid value of a group of points. While this is not as computationally simple as other filters, it allows for the attenuation of noise while allowing sudden changes in signal level to pass thru unaltered. This paper discusses the characteristics of median filters and methods of implementing them.

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Approved for public release; distribution is unlimited / A pipeline technique by Loomis and Sinha has been applied to the design of recursive digital filters. Recursive digital filters operating at hitherto impossibly high rates can be designed by this technique. An alternate technique by R. Gnanasekaran allows high speed implementation using the state-space structure directly. High throughput is also achieved by use of pipelined multiply-add modules. The actual hardware complexity will depend upon the number of pipeline stages. These techniques are used for the design of the I IR notch filter and finally, a comparison of the performance and complexity of these two techniques is presented. / http://archive.org/details/infiniteimpulser00jang / Lieutenant, Royal Thai Navy

An ISM-band frequency synthesizer is introduced in this thesis. The technique allows digital phase/frequency modulation to be achieved in a closed phase locked loop (PLL) without mixers and D/As. According to the simulation results using ADS, quantization noise will be filtered by the PLL bandwidth. But the data rate is also bounded by the PLL bandwidth. Two key components of this closed-loop architecture, Gaussian filter and delta-sigma modulator have been implemented by FPGA together with the Qualcomm Q3236 synthesizer IC.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Signal conditioning is a critical element in all data telemetry systems. Data from all sensors must be band limited prior to digitization and transmission to prevent the potentially disastrous effects of aliasing. While the 6th order analog low-pass Butterworth filter has long been the de facto standard for data channel filtering, advances in digital signal processing techniques now provide a potentially better alternative. This paper describes the challenges in developing a flexible approach to adaptable data channel filtering using DSP techniques. Factors such as anti-alias filter requirements, time correlated sampling, decimation and filter delays will be discussed. Also discussed will be the implementation and relative merits and drawbacks of various symmetrical FIR and IIR filters. The discussion will be presented from an intuitive and practical perspective as much as possible.

In this thesis, a class of combinatorial optimization methods rooted in statistical mechanics and their use in signal processing applications will be discussed. The thesis consists of two separate parts. The first part deals with the rationale for my work and also covers the background information necessary to put the second part, which consists of a number of papers, in context. There are (at least) two sides to an optimization problem---the problem statement arising from an application or a design and the selection of an algorithm to solve the problem. In this work the problem statements are practical problems, of combinatorial nature, frequently encountered in signal processing and the algorithms of choice are annealing based algorithms, founded in statistical mechanics. From my work, it is my experience that solving a particular problem often leads to new developments on the part of the algorithm which, in turn, open up possibilities to apply the modified algorithm to a new set of problems, leading to a continuously improving algorithm and a growing field of applications. The included papers deal with the application of annealing optimization methods to the problems of configuring active noise and vibration control systems, digital filter design and adaptive filtering. They also describe the successive development of a highly efficient entropy-directed deterministic annealing (EDDA) optimization algorithm detailed in the final paper.