Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535047
R. D. Roberts
Orthogonal frequency division multiplexing (OFDM) is a discrete multitone (DMT) waveform that is used on dispersive channels such as the subscriber twisted pair associated with asymmetric digital subscriber line (ADSL) or with digital television terrestrial broadcasting (DTTB). Implementation is based upon the IFFT for modulation and the FFT for demodulation. Orthogonality is obtained by having the DMT carrier spacing the same as the baud rate, and having the FFT demodulation process accumulate over exactly one baud symbol. However, orthogonality can only occur if the demodulator clock is synchronized to the modulator and no frequency offsets are present. This paper discusses, in a qualitative manner, the impact of attempting to FFT demodulate the OFDM waveform if clock synchronization has not occurred and/or if frequency offsets have accumulated on the channel.
{"title":"Qualitative analysis of the impact of clock timing error and/or frequency offsets on an OFDM waveform demodulator","authors":"R. D. Roberts","doi":"10.1109/SOUTHC.1996.535047","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535047","url":null,"abstract":"Orthogonal frequency division multiplexing (OFDM) is a discrete multitone (DMT) waveform that is used on dispersive channels such as the subscriber twisted pair associated with asymmetric digital subscriber line (ADSL) or with digital television terrestrial broadcasting (DTTB). Implementation is based upon the IFFT for modulation and the FFT for demodulation. Orthogonality is obtained by having the DMT carrier spacing the same as the baud rate, and having the FFT demodulation process accumulate over exactly one baud symbol. However, orthogonality can only occur if the demodulator clock is synchronized to the modulator and no frequency offsets are present. This paper discusses, in a qualitative manner, the impact of attempting to FFT demodulate the OFDM waveform if clock synchronization has not occurred and/or if frequency offsets have accumulated on the channel.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114997711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535116
O. Kopelman
Not long ago, Xerox used 600 engineers to design a 50 page/minute $150,000 color printer in only three years, while the previous black-and-white took them over six years to complete. Here, the author describes how Xerox's financial health increasingly depends on executing "just-in-time product development", or JITPD. Lagging the market by taking too long to develop and release a product can prove disastrous, while proper execution of JITPD results in tremendous rewards. This paper gives some insight into how to accelerate engineering development times by up to 50 percent. It explains how to practice the three secrets to quality rapid product development (QRPD), a management methodology for developing products in half the time.
{"title":"The 3 secrets to developing products in half the time","authors":"O. Kopelman","doi":"10.1109/SOUTHC.1996.535116","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535116","url":null,"abstract":"Not long ago, Xerox used 600 engineers to design a 50 page/minute $150,000 color printer in only three years, while the previous black-and-white took them over six years to complete. Here, the author describes how Xerox's financial health increasingly depends on executing \"just-in-time product development\", or JITPD. Lagging the market by taking too long to develop and release a product can prove disastrous, while proper execution of JITPD results in tremendous rewards. This paper gives some insight into how to accelerate engineering development times by up to 50 percent. It explains how to practice the three secrets to quality rapid product development (QRPD), a management methodology for developing products in half the time.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121093753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535125
R. A. Easton
This paper describes two examples of state of the art digital video cameras which provide features which can enhance the ease and/or accuracy of product quality inspection. One camera incorporates a progressive scan CCD and a built-in frame store allowing capture of high resolution still images of fast moving objects without the need for a strobe light, mechanical shutter, or external frame grabber. The second camera incorporates digital signal processing for improved dynamic range, color balance, and detail enhancement to allow more accurate determination of color or contrast attributes of objects being inspected. Video cameras can be used with visual monitors and/or computers with frame grabbers to overcome human visual limitations such as inability to freeze motion of fast moving objects or to see well in dim light or they can reduce the need for human interaction by providing visual data for pattern recognition. Video cameras have also traditionally had limitations relative to the human observer or film cameras with respect to dynamic range and color tracking.
{"title":"Smart digital cameras for product quality inspection","authors":"R. A. Easton","doi":"10.1109/SOUTHC.1996.535125","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535125","url":null,"abstract":"This paper describes two examples of state of the art digital video cameras which provide features which can enhance the ease and/or accuracy of product quality inspection. One camera incorporates a progressive scan CCD and a built-in frame store allowing capture of high resolution still images of fast moving objects without the need for a strobe light, mechanical shutter, or external frame grabber. The second camera incorporates digital signal processing for improved dynamic range, color balance, and detail enhancement to allow more accurate determination of color or contrast attributes of objects being inspected. Video cameras can be used with visual monitors and/or computers with frame grabbers to overcome human visual limitations such as inability to freeze motion of fast moving objects or to see well in dim light or they can reduce the need for human interaction by providing visual data for pattern recognition. Video cameras have also traditionally had limitations relative to the human observer or film cameras with respect to dynamic range and color tracking.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124837921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535044
C. S. Turner
Several oscillator forms are described along with sample code and a continuously variable frequency, amplitude stabilized quadrature oscillator is developed. While this last form seems to be a bit convoluted, its execution is straight forward. It needs only four memory locations, two for the outputs and two for the feedback values. These four locations may be combined into two long memory locations as is done in the sample macros. The quadrature oscillator is not only extremely flexible in that it finds numerous uses in modulators and demodulators, but this implementation also allows for easy control. Also, the efficiency of the oscillators allows one to design a radio with a general purpose DSP with an IF in the 100 kHz range. An ASIC could execute the algorithm at a much higher rate.
{"title":"A discrete time oscillator for a DSP based radio","authors":"C. S. Turner","doi":"10.1109/SOUTHC.1996.535044","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535044","url":null,"abstract":"Several oscillator forms are described along with sample code and a continuously variable frequency, amplitude stabilized quadrature oscillator is developed. While this last form seems to be a bit convoluted, its execution is straight forward. It needs only four memory locations, two for the outputs and two for the feedback values. These four locations may be combined into two long memory locations as is done in the sample macros. The quadrature oscillator is not only extremely flexible in that it finds numerous uses in modulators and demodulators, but this implementation also allows for easy control. Also, the efficiency of the oscillators allows one to design a radio with a general purpose DSP with an IF in the 100 kHz range. An ASIC could execute the algorithm at a much higher rate.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114935465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535118
H. I. Fahmy, C. Douligeris
Simulation tools improves the designer's understanding of the system beyond what intuition or analytical models alone can provide. We present, NAMS an automated approach for communication networks modeling, simulation, and performance evaluation to provide an easy-to-use, flexible simulation tool for rapidly constructing a variety of "complete" network models. NAMS receives the configuration of the network to be modeled or simulated in a specific format, uses the built-in models for the key hardware devices and protocols in a network simulation tool, puts these models together using programming interfaces to form a high level network model representing the received network configuration compiles the network model into an executable simulation generates the simulation environment, generates an appropriate performance evaluation methodology, executes the simulation, and reports the performance indices back to the system operator. NAMS is intended to be open ended to the extent that new technology/protocol options can be introduced into the system without significant effort.
{"title":"Automatic network modeling, simulation and performance evaluation","authors":"H. I. Fahmy, C. Douligeris","doi":"10.1109/SOUTHC.1996.535118","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535118","url":null,"abstract":"Simulation tools improves the designer's understanding of the system beyond what intuition or analytical models alone can provide. We present, NAMS an automated approach for communication networks modeling, simulation, and performance evaluation to provide an easy-to-use, flexible simulation tool for rapidly constructing a variety of \"complete\" network models. NAMS receives the configuration of the network to be modeled or simulated in a specific format, uses the built-in models for the key hardware devices and protocols in a network simulation tool, puts these models together using programming interfaces to form a high level network model representing the received network configuration compiles the network model into an executable simulation generates the simulation environment, generates an appropriate performance evaluation methodology, executes the simulation, and reports the performance indices back to the system operator. NAMS is intended to be open ended to the extent that new technology/protocol options can be introduced into the system without significant effort.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116441544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535110
H. J. Delgado, L. Fausett
Successive over-relaxation (SOR) can be an efficient iterative method of solving linear systems of equations. However, parallel implementation depends on an appropriate structure in the coefficient matrix; for systems arising from discretization of the Poisson equation, a red-black ordering of the unknowns is suitable. One difficulty in utilizing SOR is the necessity of choosing a good value for the relaxation parameter, /spl omega/. We present a neural network for solving the Poisson equation applied to electrostatics. The neural network learns a good value for /spl omega/ as it solves the linear system. The algorithm is based on the standard parallel SOR method. The performance of the sequential SOR and Jacobi methods are compared with the neural network for two sample problems.
{"title":"Parallel solution of a linear system using an SOR neural network","authors":"H. J. Delgado, L. Fausett","doi":"10.1109/SOUTHC.1996.535110","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535110","url":null,"abstract":"Successive over-relaxation (SOR) can be an efficient iterative method of solving linear systems of equations. However, parallel implementation depends on an appropriate structure in the coefficient matrix; for systems arising from discretization of the Poisson equation, a red-black ordering of the unknowns is suitable. One difficulty in utilizing SOR is the necessity of choosing a good value for the relaxation parameter, /spl omega/. We present a neural network for solving the Poisson equation applied to electrostatics. The neural network learns a good value for /spl omega/ as it solves the linear system. The algorithm is based on the standard parallel SOR method. The performance of the sequential SOR and Jacobi methods are compared with the neural network for two sample problems.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122163706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535048
D. Chester
While most of the attention in the open literature paid to digital intermediate frequency (IF) technology has addressed digital down conversion architectures, digital up conversion architectures are just as important and can be equally beneficial. For the past few years Harris Semiconductor has been experimenting with various single and multiple channel digital up converter architectures for economical implementations of wireless transmitters. This paper gives a top level overview of the fundamentals of digital up conversion and various architectures which have the potential for widespread use in wireless systems.
{"title":"Digital IF up conversion for economical wireless implementations","authors":"D. Chester","doi":"10.1109/SOUTHC.1996.535048","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535048","url":null,"abstract":"While most of the attention in the open literature paid to digital intermediate frequency (IF) technology has addressed digital down conversion architectures, digital up conversion architectures are just as important and can be equally beneficial. For the past few years Harris Semiconductor has been experimenting with various single and multiple channel digital up converter architectures for economical implementations of wireless transmitters. This paper gives a top level overview of the fundamentals of digital up conversion and various architectures which have the potential for widespread use in wireless systems.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128418863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535046
J. R. Doner
In cellular telephony, systems are designed to operate with a probability of 0.01 or 0.02 that a subscriber will be blocked from attempting a call at any randomly chosen moment. This design constraint, called the blocking probability, is satisfied by supplying a certain number of channels relative to the expected traffic load of the cell at worst case (busy hour) loading. The relationship between the cell's expected traffic level and the number of channels needed by the system is traditionally characterized in terms of a probability density called the Erlang B distribution. There are, however, a number of telephony systems where this assumption of uncorrelated channel demand may not hold. Since these systems operate under demand conditions not assumed in the derivation of the Erlang B density, a question arises as to whether the Erlang B distribution can accurately assess the number of channels required to meet a specified blocking probability. This paper provides an exact probabilistic analysis of this situation and explores to what extent the results are different from those obtained by using the Erlang B density.
{"title":"An analytical model for telephone systems with correlated channel demand","authors":"J. R. Doner","doi":"10.1109/SOUTHC.1996.535046","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535046","url":null,"abstract":"In cellular telephony, systems are designed to operate with a probability of 0.01 or 0.02 that a subscriber will be blocked from attempting a call at any randomly chosen moment. This design constraint, called the blocking probability, is satisfied by supplying a certain number of channels relative to the expected traffic load of the cell at worst case (busy hour) loading. The relationship between the cell's expected traffic level and the number of channels needed by the system is traditionally characterized in terms of a probability density called the Erlang B distribution. There are, however, a number of telephony systems where this assumption of uncorrelated channel demand may not hold. Since these systems operate under demand conditions not assumed in the derivation of the Erlang B density, a question arises as to whether the Erlang B distribution can accurately assess the number of channels required to meet a specified blocking probability. This paper provides an exact probabilistic analysis of this situation and explores to what extent the results are different from those obtained by using the Erlang B density.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124653625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535134
T. Culter
The rapid growth in portable devices has been well documented and all indications are that the growth will continue at a torrid pace. This increase in growth has been accompanied by an increase in the power and functionality of the various devices and, consequently, increased requirements of their power devices. The authors describe how the use of long run-time, high energy storage, lightweight rechargeable batteries can be used for such applications. This paper first looks at rechargeable zinc-air battery technology in comparison with other rechargeable battery technologies. The paper then presents details of designing a portable computer based on rechargeable zinc-air secondary batteries. The information is equally applicable to any portable electronic device.
{"title":"A design guide for rechargeable zinc-air battery technology","authors":"T. Culter","doi":"10.1109/SOUTHC.1996.535134","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535134","url":null,"abstract":"The rapid growth in portable devices has been well documented and all indications are that the growth will continue at a torrid pace. This increase in growth has been accompanied by an increase in the power and functionality of the various devices and, consequently, increased requirements of their power devices. The authors describe how the use of long run-time, high energy storage, lightweight rechargeable batteries can be used for such applications. This paper first looks at rechargeable zinc-air battery technology in comparison with other rechargeable battery technologies. The paper then presents details of designing a portable computer based on rechargeable zinc-air secondary batteries. The information is equally applicable to any portable electronic device.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126704507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-06-25DOI: 10.1109/SOUTHC.1996.535056
J. Levin, M. Eaton, D. Metcalf
We describe a project whose purpose is to bring together two technologies: CD-ROM technology, used widely to deliver training programs; and the Internet, used widely for communications. Bringing together these two technologies will make possible the ability to combine powerful training resources through CD-ROM with direct communications to the subject matter expert.
{"title":"CD-ROM based training: Interacting with the subject matter expert via the Web","authors":"J. Levin, M. Eaton, D. Metcalf","doi":"10.1109/SOUTHC.1996.535056","DOIUrl":"https://doi.org/10.1109/SOUTHC.1996.535056","url":null,"abstract":"We describe a project whose purpose is to bring together two technologies: CD-ROM technology, used widely to deliver training programs; and the Internet, used widely for communications. Bringing together these two technologies will make possible the ability to combine powerful training resources through CD-ROM with direct communications to the subject matter expert.","PeriodicalId":199600,"journal":{"name":"Southcon/96 Conference Record","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125468201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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