Pub Date : 1988-10-23DOI: 10.1109/MILCOM.1988.13433
Chiu Chen-Shu
The code segments generated by a pseudorandom noise generator are divided into groups according to the number of the chips taking on the value -1 in each segment, or equivalently according to the imbalance in the numbers of -1s and 1s. The author examines the average residual interfering power seen at the receiver baseband when the segments from each group are used for the despreading operation. It is found that such a power either increases or decreases with the degree of imbalance, depending on whether an interfering state discriminator output is positive or negative. The suppression performance of the conventional direct-sequence spread-spectrum receiver by using code segments with either large or small imbalances.<>
{"title":"Interference suppression performance of an adaptive direct sequence spread spectrum receiver","authors":"Chiu Chen-Shu","doi":"10.1109/MILCOM.1988.13433","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13433","url":null,"abstract":"The code segments generated by a pseudorandom noise generator are divided into groups according to the number of the chips taking on the value -1 in each segment, or equivalently according to the imbalance in the numbers of -1s and 1s. The author examines the average residual interfering power seen at the receiver baseband when the segments from each group are used for the despreading operation. It is found that such a power either increases or decreases with the degree of imbalance, depending on whether an interfering state discriminator output is positive or negative. The suppression performance of the conventional direct-sequence spread-spectrum receiver by using code segments with either large or small imbalances.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"19 1","pages":"469-475 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74936320","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13486
A. H. Abdelmonem, T. Saadawi
The authors develop an analytic model for evaluating and optimizing the performance of an asynchronous code-division multiple-access (CDMA) network using orthogonal codes. The analysis shows that spread-spectrum, single-hop, simultaneous successful transmissions are possible by being separable in signal space. A two-dimensional Markov chain model for an asynchronous CDMA network has been developed and numerical examples are considered. The authors have calculated state occupation probabilities, and derived an expression which describes the throughput per user pair, the network throughput, the average packet delay, channel backlog, and channel capacity.<>
{"title":"Performance analysis of an asynchronous spread spectrum packet radio network","authors":"A. H. Abdelmonem, T. Saadawi","doi":"10.1109/MILCOM.1988.13486","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13486","url":null,"abstract":"The authors develop an analytic model for evaluating and optimizing the performance of an asynchronous code-division multiple-access (CDMA) network using orthogonal codes. The analysis shows that spread-spectrum, single-hop, simultaneous successful transmissions are possible by being separable in signal space. A two-dimensional Markov chain model for an asynchronous CDMA network has been developed and numerical examples are considered. The authors have calculated state occupation probabilities, and derived an expression which describes the throughput per user pair, the network throughput, the average packet delay, channel backlog, and channel capacity.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"36 1","pages":"823-829 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73875098","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13370
J. Kozłowski, B. Ragsdale
The authors address the use of video communications with commercial telephone and satellite services as a cost-effective means of long-distance problem solving and teletraining for US Government applications. A primary objective of this feasibility study and pilot demonstration is to evaluate various video-compression codecs, interactive computer technology, and high-resolution graphics transmission equipment working with government encryption devices over multiple 56-kb telephone lines, or ISDN compatible 64-kb satellite circuits. It is concluded that the use of compressed video imagery, toll quality audio, and high-resolution graphics over multiple 64-kb or 128-kb/s satellite circuits is a proven technology with significant cost advantages over T-1 or 1.5 Mb video circuits as provided on the defense commercial telecommunications network.<>
{"title":"Addressing the emerging technology of video image compression over commercially available terrestrial and satellite transmission circuits","authors":"J. Kozłowski, B. Ragsdale","doi":"10.1109/MILCOM.1988.13370","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13370","url":null,"abstract":"The authors address the use of video communications with commercial telephone and satellite services as a cost-effective means of long-distance problem solving and teletraining for US Government applications. A primary objective of this feasibility study and pilot demonstration is to evaluate various video-compression codecs, interactive computer technology, and high-resolution graphics transmission equipment working with government encryption devices over multiple 56-kb telephone lines, or ISDN compatible 64-kb satellite circuits. It is concluded that the use of compressed video imagery, toll quality audio, and high-resolution graphics over multiple 64-kb or 128-kb/s satellite circuits is a proven technology with significant cost advantages over T-1 or 1.5 Mb video circuits as provided on the defense commercial telecommunications network.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"61 1","pages":"69-72 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74539510","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13432
V. Wolff, R. Gooch, J. Triechler
The authors describe the specification and implementation of a sophisticated digital signal processor to be used for equalizing and demodulating high-rate, high-order quadrature-amplitude-modulated (QAM) signals used in digital radio systems. The processor uses state-of-the-art algorithms as well as the latest high-speed CMOS VLSI technology to achieve a processing rate in excess of 10 gigamultiply/adds per second. The system exhibits several unique features; in particular, 40 Mband signals can be processed with 64-tap equalizer and the functions of baud and carrier recovery are implemented digitally. The signal processing problems to be solved are described, and from them a set of requirements is developed. A summary of the algorithms needed to recover symbol timing, equalize the incoming signals, and remove carrier offset is provided. A brief discussion of the hardware tradeoffs is followed by a detailed description of the system design.<>
{"title":"Specification and development of an equalizer-demodulator for wideband digital microwave radio signals","authors":"V. Wolff, R. Gooch, J. Triechler","doi":"10.1109/MILCOM.1988.13432","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13432","url":null,"abstract":"The authors describe the specification and implementation of a sophisticated digital signal processor to be used for equalizing and demodulating high-rate, high-order quadrature-amplitude-modulated (QAM) signals used in digital radio systems. The processor uses state-of-the-art algorithms as well as the latest high-speed CMOS VLSI technology to achieve a processing rate in excess of 10 gigamultiply/adds per second. The system exhibits several unique features; in particular, 40 Mband signals can be processed with 64-tap equalizer and the functions of baud and carrier recovery are implemented digitally. The signal processing problems to be solved are described, and from them a set of requirements is developed. A summary of the algorithms needed to recover symbol timing, equalize the incoming signals, and remove carrier offset is provided. A brief discussion of the hardware tradeoffs is followed by a detailed description of the system design.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"431 1","pages":"461-467 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76492126","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13368
K. Okazaki, A. Sasama, S. Unagami
The authors propose a 4.8-kbps voice-coding algorithm using pitch-synchronous discrete Fourier transform (DFT). This algorithm combines time-scale compression with pitch-synchronous DFT spectrum coding. It also discards the time-compressed signal-phase information and the nonharmonic spectral components to reduce the amount of information processes. Simulation results show that the reproduced sound quality is good. Processing delay is about 80 ms, without including operation time.<>
{"title":"A 4.8 kbps voice coding using pitch synchronous DFT","authors":"K. Okazaki, A. Sasama, S. Unagami","doi":"10.1109/MILCOM.1988.13368","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13368","url":null,"abstract":"The authors propose a 4.8-kbps voice-coding algorithm using pitch-synchronous discrete Fourier transform (DFT). This algorithm combines time-scale compression with pitch-synchronous DFT spectrum coding. It also discards the time-compressed signal-phase information and the nonharmonic spectral components to reduce the amount of information processes. Simulation results show that the reproduced sound quality is good. Processing delay is about 80 ms, without including operation time.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"513 1","pages":"57-61 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77084630","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13456
R. Iltis, J. Ritcey
A fast frequency-hopped (FFH) receiver is described which uses a prewhitening filter to reject narrowband interference. It is shown that using an appropriate fractional tap spacing, the interference can be estimated independently of the desired signal. Bit-error-rate results are presented for the receiver for linear square-law combining. The results compare favorably to those obtained by maximal-ratio combining.<>
{"title":"Interference rejection in FFH systems using least-squares estimation techniques","authors":"R. Iltis, J. Ritcey","doi":"10.1109/MILCOM.1988.13456","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13456","url":null,"abstract":"A fast frequency-hopped (FFH) receiver is described which uses a prewhitening filter to reject narrowband interference. It is shown that using an appropriate fractional tap spacing, the interference can be estimated independently of the desired signal. Bit-error-rate results are presented for the receiver for linear square-law combining. The results compare favorably to those obtained by maximal-ratio combining.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"59 1","pages":"631-635 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84118401","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13453
Chun-Meng Su, L. Milstein
A digital joint phase/timing tracking loop for a coherent frequency-hopped spread-spectrum system is analyzed for both training mode and tracking performance. Under minor assumptions, the phase error is modeled as a homogeneous finite Markov chain. The length of the training period, the approximate probability of entering the tracking range, the steady-state average error probability, and the mean-time to loss-of-lock are derived. The effects of both nonzero RF phase error and cubic channel phase response are presented. It is shown that the performance of the system can be designed to be close to that of a perfectly synchronized system.<>
{"title":"The analysis of a coherent frequency hopped spread spectrum system","authors":"Chun-Meng Su, L. Milstein","doi":"10.1109/MILCOM.1988.13453","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13453","url":null,"abstract":"A digital joint phase/timing tracking loop for a coherent frequency-hopped spread-spectrum system is analyzed for both training mode and tracking performance. Under minor assumptions, the phase error is modeled as a homogeneous finite Markov chain. The length of the training period, the approximate probability of entering the tracking range, the steady-state average error probability, and the mean-time to loss-of-lock are derived. The effects of both nonzero RF phase error and cubic channel phase response are presented. It is shown that the performance of the system can be designed to be close to that of a perfectly synchronized system.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"69 1","pages":"611-615 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84281509","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13360
S. Ahamed
The author reports the fiber-optic simulations necessary to construct integrated fiber-optic devices. The accurate computation of the lightwave device performance is essential in the design of the tightly coupled integrated circuits (ICs). The author presents lightwave design software (in Fortran with extensive graphics) that offers the designer the simulation results as databases containing the input signals to initiate the IC design or verify their function. This online microcomputer-based simulation software can be used for the analysis and design of fiber-optic data transmission links in large data communication networks. It is concluded that the microcomputer simulation and computer-aided design facility can be effectively used in the design of typical local-subscriber and metropolitan-area networks.<>
{"title":"The integration of fiber optic simulations with integrated circuit design","authors":"S. Ahamed","doi":"10.1109/MILCOM.1988.13360","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13360","url":null,"abstract":"The author reports the fiber-optic simulations necessary to construct integrated fiber-optic devices. The accurate computation of the lightwave device performance is essential in the design of the tightly coupled integrated circuits (ICs). The author presents lightwave design software (in Fortran with extensive graphics) that offers the designer the simulation results as databases containing the input signals to initiate the IC design or verify their function. This online microcomputer-based simulation software can be used for the analysis and design of fiber-optic data transmission links in large data communication networks. It is concluded that the microcomputer simulation and computer-aided design facility can be effectively used in the design of typical local-subscriber and metropolitan-area networks.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"26 1","pages":"13-17 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80422315","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13500
C. Ryan
Symbol synchronization in less than 10 symbol times has been achieved with a miss probability of <10/sup -8/. This fast acquisition time was achieved by using a phase rotator instead of the conventional voltage-controlled oscillator in the feedback loop. The baseband phase error correction technique is such that the quasistable lock state of conventional phase-locked loops is eliminated, thus allowing for acquisition times of less than 10 symbol times for TDMA (time-division multiaccess) applications and less than 30 symbol times for random data. Symbol rate error correction is obtained by a discriminator technique that provides for accurate tracking of the symbol rate error. The successful construction of the system in hardware operating at 100 Ms/s demonstrates the feasibility of this concept. The results are pertinent to the use of meteor-burst channels for military applications.<>
在不到10个符号时间内实现了符号同步，缺失概率为>
{"title":"Baseband implementation of fast acquisition symbol synchronizer","authors":"C. Ryan","doi":"10.1109/MILCOM.1988.13500","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13500","url":null,"abstract":"Symbol synchronization in less than 10 symbol times has been achieved with a miss probability of <10/sup -8/. This fast acquisition time was achieved by using a phase rotator instead of the conventional voltage-controlled oscillator in the feedback loop. The baseband phase error correction technique is such that the quasistable lock state of conventional phase-locked loops is eliminated, thus allowing for acquisition times of less than 10 symbol times for TDMA (time-division multiaccess) applications and less than 30 symbol times for random data. Symbol rate error correction is obtained by a discriminator technique that provides for accurate tracking of the symbol rate error. The successful construction of the system in hardware operating at 100 Ms/s demonstrates the feasibility of this concept. The results are pertinent to the use of meteor-burst channels for military applications.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"124 1","pages":"927-931 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91487558","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 : 1988-10-23DOI: 10.1109/MILCOM.1988.13457
B. Sklar
Trellis-coded modulation (TCM) is defined and described with respect to code-to-signal mapping and coding for QAM. Also summarized are the evolution and underlying principles of TCM and how TCM schemes achieve coding gains without bandwidth expansion. An example is used to illustrate a simple implementation of such a coding scheme.<>
{"title":"A tutorial on convolution coding for M-ary signals-trellis-coded modulation","authors":"B. Sklar","doi":"10.1109/MILCOM.1988.13457","DOIUrl":"https://doi.org/10.1109/MILCOM.1988.13457","url":null,"abstract":"Trellis-coded modulation (TCM) is defined and described with respect to code-to-signal mapping and coding for QAM. Also summarized are the evolution and underlying principles of TCM and how TCM schemes achieve coding gains without bandwidth expansion. An example is used to illustrate a simple implementation of such a coding scheme.<<ETX>>","PeriodicalId":66166,"journal":{"name":"军事通信技术","volume":"2 1","pages":"637-645 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1988-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89918104","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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