Notification:
We are currently experiencing intermittent issues impacting performance. We apologize for the inconvenience.
By Topic

Communications, IEEE Transactions on

Issue 7 • Date July 1973

Filter Results

Displaying Results 1 - 17 of 17
  • [Front cover and table of contents]

    Publication Year: 1973 , Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (149 KB)  
    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1973 , Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (188 KB)  
    Freely Available from IEEE
  • A Modified Intersymbol Interference Error Bound

    Publication Year: 1973 , Page(s): 862
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    An improvement on Saltzberg's 1968 bound is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Acquisition Behavior of Generalized Tracking Systems in the Absence of Noise

    Publication Year: 1973 , Page(s): 820 - 826
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    This paper describes a new method for analyzing the acquisition behavior of a second-order generalized tracking system in the absence of noise. In particular it allows closed-form expressions of the pull-in range and of the frequency acquisition time for any type of loop nonlinearity. The results of the present analysis are compared with those already known in the literature and with others obtained via the numerical solution of the system equation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Expected Values of Functions of Quantized Random Variables

    Publication Year: 1973 , Page(s): 850 - 854
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    The computation of expected values of functions of quantized random variables is treated by sampling theory methods, as an extension of Widrow's work on the statistical theory of quantization. It is shown that such expected values can often be evaluated readily when conditions analogous to Nyquist sampling constraints are satisfied. An example-computation of the autocorrelation of a phase-quantized angle-modulated signal-is provided to illustrate the use of the theory. Other potential areas of application are suggested. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Spread Spectrum System Using Noise Band Shift Keying

    Publication Year: 1973 , Page(s): 842 - 847
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    A new spread spectrum technique using band-limited Gaussian noise for transmission and incoherent detection at the receiver has been discussed. The proposed system called noise band shift keying (NBSK) may be considered as a modified form of the frequency-shift keying (FSK) system. In the NBSK system nonoverlapping bandlimited noise is transmitted instead of pure tones as in the FSK system and the center frequency of the noise is chosen on the basis of the binary data signal. For this system, an expression for the probability of error has been derived and it has been shown that its performance under nonfading channel conditions is identical to that of the FSK system with frequency diversity under Rayleigh fading conditions. Compared to the conventional spread spectrum systems, the proposed method is considerably more simple to implement and is attractive where adequate bandwidth is available. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of Equivalent Trunks Technique to Alternate Route Engineering

    Publication Year: 1973 , Page(s): 809 - 820
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    The grade of service of an alternate route is normally based on the average of several hourly blocking probabilities of the alternate route. The contemporary method for estimating the grade of service of an alternate route requires adjustment to the average traffic loads with appropriate correction factors in order to gain sufficient accuracy. This paper introduces the equivalent trunks technique, which can be used for approximating the alternate route grade of service without the need of adjustment to the average traffic loads. Thus, the technique is simple to use. In comparison with the results obtained by the present relatively complex method and the measured data, this technique is shown to give good accuracy. It is suggested that the preparation of engineering charts based on this technique would considerably further enhance the simplicity of its use for alternate route engineering. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effect of Co-Channel Interference on CPSK Carriers

    Publication Year: 1973 , Page(s): 783 - 790
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    This paper investigates the problem of estimating the effects of interference to a coherent phase-shift-keyed (CPSK) digital carrier. Paralleling Saltzberg [1], the principal tool utilized is the CramérChernoff bounding technique. The interference effects can be characterized by equating the larger interferers to an equivalent coherent canceling sine wave and the remaining interferers to an equivalent incoherent source of thermal noise. Subject to an envelope constraint, any allocation of the interferers between a canceling sine wave and thermal noise is allowed. Conditions are developed for the case: 1) when all the interference should be allocated to thermal noise; and 2) when as much as possible of the interference should be allocated to a canceling sine wave. This provides insight into the formal procedure of equating interference as additional thermal noise. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multicommodity Throughput in Digital Data Networks with Finite Storage

    Publication Year: 1973 , Page(s): 836 - 842
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    A model of a digital data message switching network is described. The network permits only finite storage at nodes. Discussed is a routing strategy and storage allocation to maximize throughput between many source-receiver pairs simultaneously. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Amplitude Densities of Single-Tone Amplitude-Modulated (AM) Waveforms

    Publication Year: 1973 , Page(s): 860 - 862
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    An analytical formula for the amplitude density of an almost periodic single-tone amplitude-modulated (AM) waveform is presented along with an analytical procedure to obtain the amplitude density for a periodic single-tone AM signal. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimum Versus Suboptimum Detection Under the Poisson Regime--Application to Optical Communications Using Biphase and Quadriphase Modulated Subcarriers

    Publication Year: 1973 , Page(s): 800 - 809
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    The performance of a maximum likelihood receiver whose input is the photoelectric current created by a modulated light beam is studied for a number of discrete modulation schemes. The performance is compared with that of a classical microwave receiver, i.e., one designed to optimize detection in a Gaussian channel. Such a receiver has the advantages of availability, simplicity, ease of implementation, and greater tolerance to slow photodetector response and is an obvious candidate for suboptimum detection. Procedures for calculating receiver performance in the Poisson regime by the tilted probability density technique are described and applied specifically to modulation schemes employing one or more subcarriers that are biphase or quadriphase modulated. Results indicate that the classical receiver falls noticeably short of the optimum only at or near 100 percent modulation, where it may require at worst up to 30 percent more light power in order to equal the maximum likelihood receiver. When modulation is incomplete, or when background radiation is significant, the difference in performance is generally much smaller. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Speech Predictive Encoding Communication System for Multichannel Telephony

    Publication Year: 1973 , Page(s): 827 - 835
    Cited by:  Papers (17)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    This paper describes a speech predictive encoding communications (SPEC) system that is designed to accommodate the traffic of N PCM telephone trunks in the capacity of N/2 PCM telephone channels. The system exploits the statistics of multichannel voice communication in a manner significantly different from the technique employed in the well-known time-assignment speech interpolation (TASI) system. Specifically, the SPEC system operates at the transmitter by removing redundant speech samples during talk bursts as well as during silence intervals. The receiver remembers the most recent sample transmitted through each channel. As long as a new sample is not transmitted, the receiver simply repeats the sample value stored in its memory. Each sample from each incoming trunk is examined every 125 μs to determine which samples must be transmitted and which are redundant. Because the SPEC system operates at this high speed and predicts redundant or missing samples at the receiver, it does not produce the speech clipping effects typical of TASI-like systems. Any voice-quality degradation due to increased call load and/or speech activity is manifested as an increase in noise power. The subjective result is a graceful degradation that is virtually imperceptible to the listener. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Power Spectrum of PCM/FSK-AM/PM

    Publication Year: 1973 , Page(s): 847 - 850
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    This paper derives the power spectrum of a modulating scheme under consideration by NASA for commanding scientific satellites. In this scheme the commands are frequency-shift keyed onto a subcarrier, then the clock is amplitude modulated onto the resultant. This PCM/FSK-AM waveform is then phase modulated onto a prime carrier. The method used in the paper can be easily extended to derive the spectrums of alternate command waveforms, such as PCM/FSK-AM/ FM, PCM/PSK-AM/PM, etc. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Spectral Theory for Hybrid Modulation

    Publication Year: 1973 , Page(s): 790 - 800
    Cited by:  Papers (5)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB)  

    Certain properties of periodic signals are defined in terms of the zeros and singularities of associated analytic functions of a complex time variable z . This algebraic approach is a generalization of analytic signal theory, and leads to the conception of hybrid modulation as the superposition of two z -plane zero-singularity (ZS) patterns associated with amplitude- and angle-modulating signals, respectively. It is shown that important spectral properties of the modulated signal, such as band limitation, are explicit in the resultant pattern. Signal design is then interpreted in terms of ZS manipulation and placement. The theory is applied in a unified approach to compatible singlesideband (CSSB) modulation systems. It is shown that two types of proposed CSSB systems give rise to essentially nonband-limited output signals. The relation between conventional and single-sideband (SSB) angle modulation is also discussed in terms of their characteristic ZS patterns. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Observed 7-8 GHz Signal Attenuation During Rainfall

    Publication Year: 1973 , Page(s): 862 - 863
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    Records obtained on a microwave relay system south of Lake Michigan indicate that significant attenuation can occur during rainfall at frequencies as low as 7-8 GHz. Prolonged outages axe possible when a squall line moves along, rather than across, a relay system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Jitter Due to Pulse Stuffing Synchronization

    Publication Year: 1973 , Page(s): 854 - 859
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    Expressions for calculating the magnitudes and frequencies of jitter components due to the pulse stuffing process are derived by means of a Fourier transform of the pulse stuffing jitter waveform (PSJW) for the cases where the housekeeping bit does and does not affect the stuffed positions. Previously, the latter case has always been assumed. The difference between the two cases is a function of the multiplex format, the number of cells in the synchronizer store and the type of phase detector used. The effect of the housekeeping bit is to increase the number of jitter components in the frequency domain and the store size requirement for waiting time jitter. With a reasonably low desynchronizer bandwidth, the desynchronizer output jitter can be smaller than in the ideal case previously considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synchronization Systems in Communication and Control

    Publication Year: 1973 , Page(s): 864 - 865
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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