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DFB-DCPBH InGaAsP/InP lasers for 1550 nm optical communication systems 用于1550nm光通信系统的DFB-DCPBH InGaAsP/InP激光器
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175645
R. F. Neto, I. de Faria, A. Sachs, W. de Carvalho, J. R. Caumo, A.C.G. Bordeaux Rego
{"title":"DFB-DCPBH InGaAsP/InP lasers for 1550 nm optical communication systems","authors":"R. F. Neto, I. de Faria, A. Sachs, W. de Carvalho, J. R. Caumo, A.C.G. Bordeaux Rego","doi":"10.1109/ITS.1990.175645","DOIUrl":"https://doi.org/10.1109/ITS.1990.175645","url":null,"abstract":"Room-temperature CW (continuous-wave) operation of distributed feedback (DFB) double channel planar buried heterostructure (DCPBH) InGaAsP, InP lasers emitting in the 1550-nm wavelength region has been achieved. Lasing characteristics and wave propagation in a five-layer DFB waveguide were analyzed to design low threshold current and stable single longitudinal/transversal mode operation. DFB-DCPBH structures with second-order corrugation were prepared by a two-step liquid-phase epitaxial growth process. A threshold current of 50 mA at 25 degrees C and stable single longitudinal mode operation over a wide range of driving current and temperature have been obtained. Linewidth was measured both in DC conditions and in modulated conditions up to 500 MHz.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115589132","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}
引用次数: 0
On improving and optimizing the performance of existing packet-switching networks 改进和优化现有分组交换网络的性能
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175676
Z. Zesheng
{"title":"On improving and optimizing the performance of existing packet-switching networks","authors":"Z. Zesheng","doi":"10.1109/ITS.1990.175676","DOIUrl":"https://doi.org/10.1109/ITS.1990.175676","url":null,"abstract":"The author discusses a novel method for improving and optimizing the performance of existing packet-switching networks (PSN). Decreasing the inefficient information transmission in the PSN is shown to be an efficient method of improving and optimizing the performance of PSNs. The basic theory for the optimization of PSN performance is presented, and the implementation of performance optimization is described.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116028752","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}
引用次数: 0
An efficient demultiplexing algorithm for non-contiguous carriers 一种有效的非连续载波解复用算法
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175630
A.A. Thanawala, S. Kwatra, M. Jamali, J. Budinger
{"title":"An efficient demultiplexing algorithm for non-contiguous carriers","authors":"A.A. Thanawala, S. Kwatra, M. Jamali, J. Budinger","doi":"10.1109/ITS.1990.175630","DOIUrl":"https://doi.org/10.1109/ITS.1990.175630","url":null,"abstract":"A channel separation algorithm for the FDMA/TDM (frequency division multiple access/time division multiplexing) scheme is presented. A demultiplexing algorithm that would allow demultiplexing of only the carriers of interest from the wideband spectrum of the FDMA signal in a random and efficient manner is proposed. The computational requirements indicate that the proposed technique of approximation and subsequent correction is efficient when only a small number of carriers need to be demultiplexed. When compared to the conventional fast transform algorithms (such as the FFT), the efficiency of the proposed algorithm decreases as the number of carriers increases. If the number of carriers to be processed is less than 20 (out of 800), then this demultiplexing algorithm is superior to the FFT. For an earth station application where the interest may be in only a few carriers out of hundreds received, the proposed demultiplexing algorithm is highly applicable.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122751687","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}
引用次数: 0
PBXKAN: a microprocessor-based system for modernization of telephone switching stations PBXKAN:用于电话交换站现代化的基于微处理器的系统
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175588
J. M. Mata, C. S. Lima, J. Nogueira, R. Schwaner, J.A.T.L. Baptista, S. Yoshizane, F.F. Carvalho
{"title":"PBXKAN: a microprocessor-based system for modernization of telephone switching stations","authors":"J. M. Mata, C. S. Lima, J. Nogueira, R. Schwaner, J.A.T.L. Baptista, S. Yoshizane, F.F. Carvalho","doi":"10.1109/ITS.1990.175588","DOIUrl":"https://doi.org/10.1109/ITS.1990.175588","url":null,"abstract":"The PBXKAN system consists of dedicated microprocessors which replace the PBX and KAN modules of the Ericsson ARF-102 telephone exchange, improving the way of handling PBX groups and line classes. The microprocessor make it possible to perform other tasks such as traffic measurements and line supervision, besides reducing the switching time. These microprocessors are connected to an operator's terminal. The aim of the system is to improve old telephone exchanges, executing some important functions performed by the stored program control exchanges. It can also be adapted to the Siemens ESK-10000 and Standard Electric PC-1000 exchanges. The PBXKAN system is implemented and under industrialization, with some prototypes working full-time for more than a year. One of the main characteristics of the system is its capability of fault detection, localization, indication, and recovering.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124747203","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}
引用次数: 0
Vector quantization with size-constrained codebooks 具有大小约束码本的矢量量化
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175595
R. Rao, W. Pearlman, W. Finamore
{"title":"Vector quantization with size-constrained codebooks","authors":"R. Rao, W. Pearlman, W. Finamore","doi":"10.1109/ITS.1990.175595","DOIUrl":"https://doi.org/10.1109/ITS.1990.175595","url":null,"abstract":"An algorithm for calculating lower bounds to the performance of all size-constrained vector quantizers has been derived earlier. Applications to the AR(1) source have shown that these lower bounds are very close to the actual rate-distortion curves, even for small sizes of the output alphabet. In this algorithm, however, the codebook changes with rate. In a number of applications it is desirable to operate with the same codebook. The authors modify the above algorithm to calculate lower bounds to the performance of all such multirate coders. An important conclusion is that constraining the codebook vectors does not degrade performance as compared to the size-only constrained case. The authors have proposed a practical alphabet and entropy constrained vector quantizer (AECVQ). This coder is obtained by modifying the ECVQ algorithm so that the codebook remains the same for all rates.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124748035","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}
引用次数: 2
Configuration management for distributed object-oriented applications 分布式面向对象应用程序的配置管理
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175670
A. Schill, G. Blakowski
{"title":"Configuration management for distributed object-oriented applications","authors":"A. Schill, G. Blakowski","doi":"10.1109/ITS.1990.175670","DOIUrl":"https://doi.org/10.1109/ITS.1990.175670","url":null,"abstract":"A separate configuration language with associated management mechanisms has been developed. The approach supports the initial structure and placement description of a distributed object-oriented application as well as dynamic configuration changes. Moreover, configuration conditions can be stated and are checked against an actual configuration. The authors describe the configuration language, the configuration management algorithms, and the integration with the underlying object-oriented system. A first prototype of this approach has been implemented in C++ in VAX stations using the compiler construction tools Lex and Yacc.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124971689","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}
引用次数: 2
Signal theory for SONET STM-1 SONET STM-1的信号理论
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175567
G. Cariolaro, G. Iudicello
{"title":"Signal theory for SONET STM-1","authors":"G. Cariolaro, G. Iudicello","doi":"10.1109/ITS.1990.175567","DOIUrl":"https://doi.org/10.1109/ITS.1990.175567","url":null,"abstract":"The authors discuss a signal theory approach to SONET fundamental operations: (1) multiplexing of payloads, section path overheads into a SONET structure; (ii) scrambling; and (iii) conversion into a line signal. The CCITT recommendations are taken as reference, but the formulation is sufficiently general to include the operations STS of US standards. In particular, the following sequence of operations is considered: (a) multiplexing of a C-4 into a VC-4, (b) multiplexing VC-4 into a AU-4 with general pointer settlement, (c) multiplexing of an AU-4 into STM-1 (synchronous transport module-level 1). It is shown that this sequence (including scrambler) is equivalent to a linear FIR (finite impulse response) filter. As an example of application of the modules, spectral analysis after the line conversion of an STM-1 frame sequence with a specific payload is carried out.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126206919","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}
引用次数: 2
Bit rate reduction for PAL-M signal transmission using a modification of DPCM system 利用DPCM系统的改进降低PAL-M信号传输的比特率
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175665
Y. Iano, E.C. Araneda, J.B. Rickeim Filho
{"title":"Bit rate reduction for PAL-M signal transmission using a modification of DPCM system","authors":"Y. Iano, E.C. Araneda, J.B. Rickeim Filho","doi":"10.1109/ITS.1990.175665","DOIUrl":"https://doi.org/10.1109/ITS.1990.175665","url":null,"abstract":"The authors present an original scheme based on the DPCM (differential pulse code modulation) system for decreasing the redundancy contained in an image. Many computer simulations and the results can be applied to composite coding of PAL-M television signals. The basic idea is to concentrate the values before and after the quantizer to obtain a recovered image with acceptable objective and subjective quality. To achieve this target, the authors have investigated the utilization of a divider and a multiplier in the loop of traditional DPCM scheme. They obtained good performance of the scheme, taking into account the exchange between bit rate reduction efficiency and recovered picture quality.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114699010","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}
引用次数: 0
Multicoupled cavity filter applications in high capacity digital radio equipment 多耦合腔滤波器在大容量数字无线电设备中的应用
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175573
J.L. de Albuquerque Moraes, C.M. Fugimoto
{"title":"Multicoupled cavity filter applications in high capacity digital radio equipment","authors":"J.L. de Albuquerque Moraes, C.M. Fugimoto","doi":"10.1109/ITS.1990.175573","DOIUrl":"https://doi.org/10.1109/ITS.1990.175573","url":null,"abstract":"The authors present the features and general design procedures of multicoupled cavity filters using dielectric resonator technology. The advantages of using such filters in digital radios are made clear by direct comparisons of some characteristics of the most common filters that can be synthesized with multicoupled and with adjacent coupled networks. As an example, a 5 GHz filter designed to be used in 16 QAM (quadrature amplitude modulation) radio equipment with a 140-Mb/s transmission rate is shown.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121972240","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}
引用次数: 0
Carrier recovery performance in PSK systems using transmission pulses with a square root raised cosine spectrum 使用平方根提升余弦频谱传输脉冲的PSK系统的载波恢复性能
SBT/IEEE International Symposium on Telecommunications Pub Date : 1990-09-03 DOI: 10.1109/ITS.1990.175662
R. Sampaio-Neto, J. Albuquerque
{"title":"Carrier recovery performance in PSK systems using transmission pulses with a square root raised cosine spectrum","authors":"R. Sampaio-Neto, J. Albuquerque","doi":"10.1109/ITS.1990.175662","DOIUrl":"https://doi.org/10.1109/ITS.1990.175662","url":null,"abstract":"A general expression is presented for the M/sup th/ power carrier tracking loop loss. This expression is applied to assess the performance of Costas-loop type schemes in binary PSK (phase shift keying) and quadrature PSK systems, in which transmission pulses have a square-root raised-cosine spectrum and matched filters are used in the receiver. Numerical results illustrate performance sensitivity to variations of the pulse roll-off factor.<<ETX>>","PeriodicalId":405932,"journal":{"name":"SBT/IEEE International Symposium on Telecommunications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129880855","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}
引用次数: 0
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