A fast-initializing digital equalizer with on-line tracking for data communications

A theory is developed for a digital equalizer for use in reducing intersymbol interference (ISI) on high speed data communications channels. The equalizer is initialized with a single isolated transmitter pulse, provided the signal-to-noise ratio (SNR) is not unusually low, then switches to a decision directed, on-line mode of operation that allows tracking of channel variations. Conditions for optimal tap-gain settings are obtained first for a transversal equalizer structure by using a mean squared error (MSE) criterion, a first order gradient algorithm to determine the adjustable equalizer tap-gains, and a sequence of isolated initializing pulses. Since the rate of tap-gain convergence depends on the eigenvalues of a channel output correlation matrix, convergence can be improved by making a linear transformation on to obtain a new correlation matrix

Design of FIR digital filters for pulse shaping and channel equalization using time-domain optimization

Three algorithms are developed for designing finite impulse response digital filters to be used for pulse shaping and channel equalization. The first is the Minimax algorithm which uses linear programming to design a frequency-sampling filter with a pulse shape that approximates the specification in a minimax sense. Design examples are included which accurately approximate a specified impulse response with a maximum error of 0.03 using only six resonators. The second algorithm is an extension of the Minimax algorithm to design preset equalizers for channels with known impulse responses. Both transversal and frequency-sampling equalizer structures are designed to produce a minimax approximation of a specified channel output waveform. Examples of these designs are compared as to the accuracy of the approximation, the resultant intersymbol interference (ISI), and the required transmitted energy. While the transversal designs are slightly more accurate, the frequency-sampling designs using six resonators have smaller ISI and energy values

The Brownie Baker Case: Ingredients Of Success

This case study examines The Brownie Baker, which makes gourmet and specialty baked goods, from an operations management perspective.  Its product line includes brownies, muffins, Danishes, cookies, cakes, and Hispanic pastries.  Located in Fresno, California, the bakery distributes its products across much of the United States.  The Brownie Baker was acquired by president and CEO, Dennis Perkins, in 1990.   What started with four or five employees and $180,000 in annual sales has grown to 80 employees and more than 10 million dollars in sales in 2007.  Perkins’ down-to-earth, receptive management style coupled with product innovations and productivity improvements have been key ingredients in the company’s successful growth.  Perkins himself was named the Small Business Administration’s  Central California Business Person of the Year in 1999, and The Brownie Baker was awarded the Small Business Administration’s Western Region Choice Award in 2004.  This case details the operations strategies and management techniques that have led to these accomplishments

Facts from Fiction: Packaging Misinformation

Previous research established that readers learn both accurate and inaccurate information from fictional stories. The current study explored factors that might moderate the impact of misinformation. Participants read fictional stories that contain three assertions; the first two were labeled as set-up assertions, and the last were labeled as the critical assertion. First, there was a manipulation of plausibility of information within the stories by presenting either assertions with truthful information, assertions with small lies (plausible misinformation), or assertions with big lies (implausible misinformation). Second, there was manipulation of reliability of the fictional stories by presenting big lies or truthful information in the set-up assertions before the critical assertion. Each story had two set-up assertions (either both are big lies, or both are truthful) that were presented prior to the critical assertion. We expected to replicate many existing findings found within the misinformation literature. Of most interest in this study, we observed being presented with misinformation led to lower accuracy and being presented with subtle misinformation led to higher production of that misinformation on the general-knowledge test. The setup assertion manipulation interacted with the type of critical assertion in one way: When the critical assertion was presented accurately in a story, the setup assertions mattered a lot in that reliable narrators presenting true critical assertions and led to greater accuracy on the general knowledge test than when unreliable narrators presented this information

Sunrise Medical And The Quickie Wheelchair

This case profiles the Quickie Wheelchair, first developed by a group of entrepreneurs in Fresno, California and now manufactured by Sunrise Medical, the world’s leading manufacturer of customized lightweight wheelchairs. Topics such as strategy, product design, location planning, quality control, and just-in-time systems make this case suitable for use in a production and operations management course

A digital technique to compensate for time- base error in magnetic tape recording

Digital technique for compensation of time base error in magnetic tape recorder dat

Fission Power System Technology for NASA Exploration Missions

Under the NASA Exploration Technology Development Program, and in partnership with the Department of Energy (DOE), NASA is conducting a project to mature Fission Power System (FPS) technology. A primary project goal is to develop viable system options to support future NASA mission needs for nuclear power. The main FPS project objectives are as follows: 1) Develop FPS concepts that meet expected NASA mission power requirements at reasonable cost with added benefits over other options. 2) Establish a hardware-based technical foundation for FPS design concepts and reduce overall development risk. 3) Reduce the cost uncertainties for FPS and establish greater credibility for flight system cost estimates. 4) Generate the key products to allow NASA decisionmakers to consider FPS as a preferred option for flight development. In order to achieve these goals, the FPS project has two main thrusts: concept definition and risk reduction. Under concept definition, NASA and DOE are performing trade studies, defining requirements, developing analytical tools, and formulating system concepts. A typical FPS consists of the reactor, shield, power conversion, heat rejection, and power management and distribution (PMAD). Studies are performed to identify the desired design parameters for each subsystem that allow the system to meet the requirements with reasonable cost and development risk. Risk reduction provides the means to evaluate technologies in a laboratory test environment. Non-nuclear hardware prototypes are built and tested to verify performance expectations, gain operating experience, and resolve design uncertainties