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Communications, IEEE Transactions on

Issue 8 • Date August 1980

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Displaying Results 1 - 25 of 46
  • [Front cover and table of contents]

    Publication Year: 1980 , Page(s): 0
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    Freely Available from IEEE
  • Guest Editorial: Special issue on synchronization

    Publication Year: 1980 , Page(s): 1105 - 1106
    Cited by:  Papers (10)  |  Patents (1)
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    Freely Available from IEEE
  • Comments on "A study of users' buffer variations in random access satellite channels"

    Publication Year: 1980 , Page(s): 1436
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (117 KB)  

    The commentors point out a problem with equation (6) of the above-named work (ibid., vol. COM-27, pp. 857-868, June 1979) that affects the subsequent values determined in the derivations presented and may make the paper's results inconclusive. View full abstract»

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  • Author's reply

    Publication Year: 1980 , Page(s): 1436 - 1437
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    First Page of the Article
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  • Correction to "Receiver Windowing for FDM MFSK Signals"

    Publication Year: 1980 , Page(s): 1437
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    An error to equation (25) in the above-named work (ibid., vol. COM-27, pp. 1519-1527, Oct. 1979) is corrected. View full abstract»

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  • [Back cover]

    Publication Year: 1980 , Page(s): 0
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    Freely Available from IEEE
  • Carrier and Bit Synchronization in Data Communication--A Tutorial Review

    Publication Year: 1980 , Page(s): 1107 - 1121
    Cited by:  Papers (146)  |  Patents (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1648 KB)  

    This paper examines the problems of carrier phase estimation and symbol timing estimation for carrier-type synchronous digital data signals, with tutorial objectives foremost. Carrier phase recovery for suppressed-carrier versions of double sideband (DSB), vestigial sideband (VSB), and quadrature amplitude modulation (QAM) signal formats is considered first. Then the problem of symbol timing recovery for a baseband pulse-amplitude modulation (PAM) signal is examined. Timing recovery circuits based on elementary statistical properties are discussed as well as timing recovery based on maximum-likelihood estimation theory. A relatively simple approach to evaluation of timing recovery circuit performance in terms of rms jitter of the timing parameters is presented. View full abstract»

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  • Self-Noise in Synchronizers

    Publication Year: 1980 , Page(s): 1159 - 1163
    Cited by:  Papers (57)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    Synchronization of narrow-band data signals is plagued by self-noise arising from the randomness of the data stream. The disturbance can be resolved into in-phase and quadrature components with respect to the recovered carrier or clock. Only the quadrature component necessarily contributes to phase jitter of the recovered reference. Spectrum of the quadrature component, in many cases, vanishes at the reference frequency. Circuit precautions are needed to avoid cross coupling the in-phase disturbance into phase jitter. View full abstract»

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  • Stability Analysis of an Nth Power Digital Phase-Locked Loop--Part I: First-Order DPLL

    Publication Year: 1980 , Page(s): 1343 - 1354
    Cited by:  Papers (23)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    The behavior of a digital phase-locked loop (DPLL) which tracks the positive-going zero crossings of the incoming signal can be characterized by a nonlinear difference equation in the phaseerror process. This equation was first presented by Gill and Gupta for the CW loop, and modified by Osborne and Lindsey for the N th power loop. Stability results have been previously obtained for first- and second-order loops by linearizing the equation about the steady-state solution. However, in this paper, a mathematically more rigorous and powerful approach is introduced whereby the acquisition behavior is studied by formulating the equation as a fixed-point problem. Stability results can be obtained by studying the nonlinear equation directly, using theorems pertaining to the convergence behavior of the Picard iterates, e.g., Ostrowski's Theorem and the Contraction Mapping Theorem. Using this formulation, we present some new stability results (and rederive some previously obtained results) for the first- and second-order DPLL's. Then, some stability results for the third-order DPLL are derived for the first time. The first-order DPLL results appear in Part I, and the higher order DPLL results appear in Part II. View full abstract»

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  • Survey of Synchronization Techniques for a TDMA Satellite-Switched System

    Publication Year: 1980 , Page(s): 1291 - 1301
    Cited by:  Papers (4)  |  Patents (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1064 KB)  

    On-board processing of signals in a communications satellite system is rapidly becoming a reality. To meet the needs in high capacity systems, new technologies are being developed, and one of the most recent is the system called time-division multiple-access, satellite-switched (TDMA/SS) which employs multiple spot beam zones. Since TDMA is employed, it is necessary for all earth stations to synchronize their time bases to a common reference which, in this case, is the sync window connection of the satellite. Synchronization for this system is a major problem which has been examined in detail in a number of different papers. This paper provides a survey of the various techniques which have been proposed in the past and gives a comparative analysis of the advantages and disadvantages of each. Factors taken into account include timing accuracy, bit energy to noise density ratio of difference signals, estimated delay for acquiring acquisition, tracking features, microcomputer implementation, and possible improvements for the future. View full abstract»

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  • A Method for Modeling and Analysis of the Reframing Performance of Multilevel Synchronous Time Division Multiplex Hierarchies

    Publication Year: 1980 , Page(s): 1219 - 1228
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB)  

    This paper presents a method for modeling the operation of the frame synchronization algorithms of the several levels of a synchronous time division multiplex hierarchy as a Markov chain. A method, discussed elsewhere by one of the authors, is used to drastically reduce the number of states in the Markov chain and make a numerical calculation of the mean first passage times possible. The mean reframing times as a function of appropriate parameters are determined for three examples, with one approaching the complexity of a practical system. A determination of the same quantities by methods unrelated to the proposed approach gives results which are in excellent agreement. View full abstract»

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  • Frame Synchronization Techniques

    Publication Year: 1980 , Page(s): 1204 - 1213
    Cited by:  Papers (91)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1008 KB)  

    A basic theory of frame synchronization for a singlechannel digital communication system is presented, along with extensive references to the literature. The design of frame markers is discussed and comparisons are drawn with more exotic techniques such as comma-free coding. View full abstract»

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  • Network Synchronization of Random Signals

    Publication Year: 1980 , Page(s): 1260 - 1266
    Cited by:  Papers (14)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    This paper presents a unified mathematical model for studying the behavior of various network synchronization techniques, e.g., plesiochronous or independent clocks, hierarchical master-slave, delay-compensated and uncompensated network models are presented in the form of a set of nonlinear space-time matrix equations in which network interconnection matrices are manifested. Each equation in the set characterizes the diffusion of phase (time) and frequency generated at each network node. The matrices of this model define the topological structure of the network. The time-frequency model is used to characterize the timefrequency stability of the network clock ensemble. Expressions for the steady-state network frequency and the time differences between nodal clocks are derived and compared for plesiochronous, delay compensated and uncompensated networks. A network frequency stability measure is introduced, evaluated and performance comparisons are made for specific network configurations. Finally, we illustrate the steady-state frequency stability achievable when M subnetworks are connected to form a larger network. View full abstract»

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  • Tracking Performance of the Filter and Square Bit Synchronizer

    Publication Year: 1980 , Page(s): 1154 - 1158
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    This paper determines the tracking performance of a filter and square bit synchronizer loop (FSTL) for the case of NRZ symbols and a probability of data transition of 0.5. Results are compared to the early late gate tracking loop (ELGTL) and the digital transition tracking loop (DTTL). The FSTL is much easier to implement and, in addition, has a standard deviation of tracking error only about 14 percent larger than the DDTL loop. View full abstract»

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  • An Electronic Hybrid with Adaptive Balancing for Telephony

    Publication Year: 1980 , Page(s): 1399 - 1407
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (752 KB)  

    A new form of adaptive balancing hybrid is proposed for application to the two-wire to four-wire interface of a local digital switch. It is similar to an echo canceller but with a single degree of freedom and much simpler circuitry. In this paper a theory of operation of the hybrid is developed, and in a companion paper two circuit implementations and experimental results are reported. View full abstract»

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  • Phase Acquisition Statistics for Phase-Locked Loops

    Publication Year: 1980 , Page(s): 1365 - 1372
    Cited by:  Papers (17)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    Phase acquisition probabilities for phase-locked synchronizers are derived. Both self- and aided-acquisition techniques are investigated and compared. It is shown that so called "hang-up" can be prevented by using initial quadrant estimation to control appropriate slew voltage applied to VCO. View full abstract»

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  • Short Term Frequency Instability Effects in Networks of Coupled Oscillators

    Publication Year: 1980 , Page(s): 1269 - 1275
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    A set of N identical oscillators (clocks) are connected to form a mutually synchronous network. General matrix expressions are derived for the phase error spectrum at each oscillator when the network operates in the linear regime. For certain topologies of practical interest the phase error variance and the correlation between the errors at different oscillators is computed and compared in their behavior for large N . The results presented assume no thermal noise and no delay between the oscillators. However, the theory can be easily extended to include these two effects. View full abstract»

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  • An Illustration of the MAP Estimation Method for Deriving Closed-Loop Phase Tracking Topologies: The MSK Signal Structure

    Publication Year: 1980 , Page(s): 1137 - 1142
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    This paper discusses the application of MAP estimation techniques to the problem of defining tracking loops for the estimation of various signal parameters. While this method has been applied to various signal structures such as BPSK and QPSK to show the reasonableness of certain loops such as the Costas loop, it is shown that the MAP method is useful for deriving tracking structures for signals for which no previously defined tracking loops exist. The method has already been applied to the case of deriving carrier tracking loops for unbalanced quadriphase (UQPSK). The particular application chosen to illustrate the MAP technique is the MSK signal. In particular, a closed loop is derived that jointly estimates both the carrier and clock phases. View full abstract»

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  • A 140 Mbits/s Digital Transmission System for Coaxial Cable Using Partial Response Class 1 Line Code with Quantized Feedback

    Publication Year: 1980 , Page(s): 1425 - 1430
    Cited by:  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    A comparison between different line codes suitable for transmission of 140 Mbit/s digital signals over 1.2/4.4 mm coaxial cable has been made using the computer optimization program, "OPUT." One alternative, the two level partial response class 1 (PR1), is chosen and a laboratory system has been built and tested. A block diagram of the system followed by a description is given. Performance of the system is presented and commented on. It is concluded that a PR1 system can be implemented with reasonable noise margin with a repeater spacing of 2.15 km for a 1.2/4.4 mm coaxial cable. View full abstract»

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  • On False-Lock Phenomena in Carrier Tracking Loops

    Publication Year: 1980 , Page(s): 1326 - 1334
    Cited by:  Papers (4)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    The false-lock phenomena in carrier tracking loops for the suppressed carrier modulation signal, such as phase-shift keyed (PSK) signals, present serious problems to the design of digital communication systems. There are two kinds of false-lock phenomena: one is related to the loop delay time and the other is to the modulation frequency. This paper describes an analysis of the latter type obsered in the phase-lock loops (PLL's) comprising the remodulation or decision feedback. The mechanism of the false-lock phenomena is best described by using the minimum phase difference between the input modulated carrier and the voltage controlled oscillator (VC-O) output as a parameter. It is shown that the loop can be locked at the offset frequencies of \pm(m/n)f_{c} in both the sampled and nonsampled control systems, where m/n is a simple fraction and fcdenotes the modulation frequency. The lock and capture ranges for these false-lock frequencies are derived. View full abstract»

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  • Implementation of an Adaptive Balancing Hybrid

    Publication Year: 1980 , Page(s): 1408 - 1416
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (680 KB)  

    Two implementations of an adaptive balancing hybrid are described. The first is predominly analog, in which the adaptation parameter θ is a continuous analog quantity, while the second is predominly digital, in which θ has a two-bit representation. Experimental results are reported. View full abstract»

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  • Viterbi Decoder Performance in Gaussian Noise and Periodic Erasure Bursts

    Publication Year: 1980 , Page(s): 1417 - 1422
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    In this paper, we evaluate the performance of noninterleaved convolutional codes in the presence of Gaussian noise and periodic erasure bursts, with maximum likelihood (Viterbi) decoding. The results show that even for burst lengths that are a significant fraction of the code constraint length, the performance degradation is surprisingly small. It is then shown that in many of these cases the use of interleaving would provide very little performance gain. In addition, for burst lengths that are so long that interleaving is unavoidable, these results demonstrate the robustness of fixed periodic interleavers against variability in the parameters of the burst process. View full abstract»

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  • Sideband False-Lock Performance of Squaring, Fourth-Power, and Quadriphase Costas Loops for NRZ Data Signals

    Publication Year: 1980 , Page(s): 1335 - 1342
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1376 KB)  

    This paper derives the sideband false-lock margins of the short squaring, short fourth-power, long fourth-power, and quadriphase Costas loops for NRZ synchronous data streams. The falselock margins in the short fourth-power and quadriphase Costas loops are found to be 5-10 dB worse than those in the short squaring and biphase Costas loops. The extremely low false-lock margins of 3 and 4 dB in the short fourth-power loop at typical design values of the prefourth-power bandpass filter bandwidth were verified by experimental results. Also described are several experimentally tested methods for false-lock prevention. View full abstract»

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  • On Frame Synchronization of PCM Systems

    Publication Year: 1980 , Page(s): 1213 - 1218
    Cited by:  Papers (6)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    A new strategy for frame synchronization of PCM muitlplex systems which use pulse stuffing (justification) is proposed. In devising this technique, the compatibility with existing CCITT systems was taken into consideration. Comparisons between the proposed strategy and the CCITT recommended system are made in terms of average holding time, average time for detection of synchronization loss, and average synchronization recovery time. The proposed strategy proved to be significantly better in total synchronization time without sacrificing its holding time capacity. View full abstract»

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  • Joint Carrier Phase and Symbol Timing Recovery for PAM Systems

    Publication Year: 1980 , Page(s): 1121 - 1129
    Cited by:  Papers (39)  |  Patents (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    The detection of pulse amplitude modulation (PAM) carrier signals requires accurate symbol timing and carrier phase references. In most cases, it is desired to estimate these parameters directly from measurements on the received data signal. This paper adds to and unifies the theory of maximum likelihood [ML] estimation as applied to PAM timing and phase recovery. Several different estimation strategies are considered. Data-aided [DA] estimators are found which assume the transmitted data symbols are known at the receiver. Nondata-aided [NDA] estimators are found which require only knowledge of the statistics of the transmitted data symbols. Structures for estimation of symbol timing, carrier phase, and joint estimation of timing and phase are presented. The estimators are evaluated on the basis of their error variances. Relatively simple approximate expressions for these error variances are presented. These expressions allow the comparison of the effects of excess bandwidth, different modulation schemes, DA versus NDA recovery, and joint estimation versus estimation of only one parameter. A practical implementation of the ML estimator, termed a pseudo-maximum likelihood (PML) estimator, is proposed and analyzed. The performance of the PML estimator is shown to include a noise-independent, data-dependent jitter which dominates in many cases of practical interest. View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Robert Schober
University of British Columbia