Showing papers in "Bell System Technical Journal in 1968"
TL;DR: In this article, the statistical characteristics of the fields and signals in the reception of radio frequencies by a moving vehicle are deduced from a scattering propagation model, assuming that the field incident on the receiver antenna is composed of randomly phased azimuthal plane waves of arbitrary angle angles.
Abstract: The statistical characteristics of the fields and signals in the reception of radio frequencies by a moving vehicle are deduced from a scattering propagation model. The model assumes that the field incident on the receiver antenna is composed of randomly phased azimuthal plane waves of arbitrary azimuth angles. Amplitude and phase distributions and spatial correlations of fields and signals are deduced, and a simple direct relationship is established between the signal amplitude spectrum and the product of the incident plane waves' angular distribution and the azimuthal antenna gain. The coherence of two mobile-radio signals of different frequencies is shown to depend on the statistical distribution of the relative time delays in the arrival of the component waves, and the coherent bandwidth is shown to be the inverse of the spread in time delays. Wherever possible theoretical predictions are compared with the experimental results. There is sufficient agreement to indicate the validity of the approach. Agreement improves if allowance is made for the nonstationary character of mobile-radio signals.
2,087 citations
TL;DR: This is a summary of data from an extensive analysis of on-off speech patterns in 16 experimental telephone conversations, determined by a fixed threshold speech detector having certain rules for rejecting noise and for filling in short gaps.
Abstract: This is a summary of data from an extensive analysis of on-off speech patterns in 16 experimental telephone conversations. The on-off patterns are determined by a fixed threshold speech detector having certain rules for rejecting noise and for filling in short gaps (for example, from stop consonants). Distributions are obtained for ten events, including talk-spurts, pauses, double talking (simultaneous speech from both parties), mutual silence, etc. Particular emphasis is placed on events surrounding interruptions. The entire analysis is performed for three speech detector thresholds, since most of the data are strongly influenced by choice of threshold. Observations are made about the influence of threshold on the data, properties of speech invariant with choice of threshold, and differences between male and female speech patterns.
486 citations
TL;DR: A decomposition theorem shows every group code to be equivalent to a direct sum of certain basic group codes generated by real-irreducible representations of a finite group associated with the code.
Abstract: A class of codes for use on the Gaussian channel, called group codes, is defined and investigated. Roughly speaking, all words in a group code are on an equal footing: each has the same error probability and the same disposition of neighbors. A decomposition theorem shows every group code to be equivalent to a direct sum of certain basic group codes generated by real-irreducible representations of a finite group associated with the code. Some theorems on distances between words in group codes are demonstrated. The difficult problem of finding group codes with large nearest neighbor distance is discussed in detail.
235 citations
TL;DR: In this paper, the forward and reverse I-V characteristics of Schottky barrier diodes with PtSi contacts and diffused guard rings were investigated and the forward current was shown to follow the expression I f = I s exp (qV/nkT) over eight orders of magnitude in current with I s = 10−12 A and n = 1.02.
Abstract: Metal-semiconductor diodes with near-ideal forward and reverse I-V characteristics have been fabricated using PtSi contacts and diffused guard rings. Typically, for a device with an area of 2.5 × 10−6 cm2 made on an n-type (111) oriented, 0.35 ohm-cm silicon epitaxial substrate, the forward current follows the expression I f = I s exp (qV/nkT) over eight orders of magnitude in current with I s = 10−12 A and n = 1.02. The reverse breakdown is sharp and occurs at the theoretical breakdown voltage of p+ n silicon junctions of the same n-type doping. The premature breakdown observed in nearly all previous Schottky barrier diodes has been shown to be caused by electrode sharp-edge effects. Besides giving sharp breakdown voltage, the guard ring also eliminates anomalously high leakage currents, yet still retains the fast recovery time characteristic common to other Schottky barriers. Typically, the recovery time measured at 10 ma is less than 0.1 ns, the resolution of the measurement.
162 citations
TL;DR: In this paper, a Fourier-Bessel series of N terms is used to express the difference pattern in a manner similar to Taylor's treatment of the sum pattern, and the Fourier coefficients are derived for both the circular aperture series and the different pattern series.
Abstract: The flexibility of modern monopulse radar antenna systems makes possible the independent optimization of sum and difference patterns. The two parameter difference pattern, developed here for the circular aperature antenna, is designed to have nearly equal sidelobes similar to those of the Taylor sum pattern. The difference pattern is asymptotic to a model difference pattern which has the greatest slope (angle sensitivity) for a given sidelobe level. The model function is unrealizable because it has uniform sidelobes which are infinite in extent. The two parameter difference pattern is realizable and is expressed in a Fourier — Bessel series of N terms in a manner similar to Taylor's treatment of the sum pattern. The other parameter, A, controls sidelobe level. Comprehensive tables of the Fourier — Bessel coefficients are given for both the circular aperture series and the difference pattern series. Directivity and angle sensitivity are investigated and found to have maximum values that decrease as sidelobe level decreases. The monopulse system performance using the asymptotic difference pattern and the Taylor sum pattern compares favorably with a maximum likelihood angle estimation system. Development of a line source difference pattern is presented in the appendix.
162 citations
TL;DR: A systematic approach to the analysis and construction of channel codes for digital baseband transmission is presented and state-dependent coding of both fixed and variable length is a direct result.
Abstract: A systematic approach to the analysis and construction of channel codes for digital baseband transmission is presented. The structure of the codes is dominated by the set of requirements imposed by channel characteristics and system operation. These requirements may be translated into symbol sequence properties which, in turn, specify a set of permissible sequence states. State-dependent coding of both fixed and variable length is a direct result. Properties of such codes are discussed and two examples are presented.
129 citations
TL;DR: In this article, the attenuation and scattering of laser beams by rain, fog, and snow have been calculated and measured at 0.63, 3.5, and 10.6μ.
Abstract: The attenuation and scattering of laser beams by rain, fog, and snow have been calculated and measured at 0.63, 3.5, and 10.6μ. Attenuation of the infrared wavelengths by light fog is up to one order of magnitude less than at 0.63μ. But for dense fog, calculation shows that the attenuation at 10.6μ can exceed 40 dB per km. It is found that attenuation by rain can be calculated to good accuracy from average path rain rates provided that forward scattering is taken into account; this scattering reduces the attenuation. Measurements of propagation through precipitation over a 2.6 km path are discussed in detail and are found to be consistent with predictions. The wavelength dependence of attenuation is found to vary from one fog to another because of different drop-size distributions. Attenuation of 0.63μ in rain showers is about 20 per cent less than at 3.5μ and is, of course, much less than the attenuation in fog. But even for extremely heavy rain showers, the 0.63μ attenuation never exceeded 20 dB per km, which is less than the attenuation of millimeter waves under such conditions. Both the attenuation and foreward scattering properties of snow appear to be between those of fog and rain.
113 citations
TL;DR: In this paper, it was shown that the noise behavior of a pumped resistive diode which does not contain 1/f noise sources can be derived in a very simple way from Nyquist's theorem.
Abstract: This paper discusses certain important aspects of the noise behavior of a pumped resistive diode containing shot and thermal noise sources. The derivation of the following result has a central role in the discussion. It is shown that the noise behavior of a pumped diode which does not contain 1/f noise sources can be derived in a very simple way from Nyquist's theorem. This follows from the fact that the small-signal terminal behavior of such a diode can always be represented, in the frequency range of practical interest, by means of a connection of two linear and time-invariant networks of which one is noiseless and the other is dissipative, contains only thermal noise sources and is held at a uniform temperature.
91 citations
TL;DR: The capabilities of memories are discussed, and it is shown that there exist memories, constructed entirely from unreliable components of the assumed type, which have nonzero information storage capacities.
Abstract: This is the first of two papers which consider the theoretical capabilities of computing systems designed from unreliable components This paper discusses the capabilities of memories; the second paper discusses the capabilities of entire computing systems Both present existence theorems analogous to the existence theorems of information theory The fundamental result of information theory is that communication channels have a capacity, C, such that for all information rates less than C, arbitrarily reliable communication can be achieved In analogy with this result, it is shown that each type of memory has an information storage capacity, C, such that for all memory redundancies greater than 1/C arbitrarily reliable information storage can be achieved Since memory components malfunction in many different ways, two representative models for component malfunctions are considered The first is based on the assumption that malfunctions of a particular component are statistically independent from one use to another The second is based on the assumption that components fail permanently but that bad components are periodically replaced with good ones In both cases, malfunctions in different components are assumed to be independent For both models it is shown that there exist memories, constructed entirely from unreliable components of the assumed type, which have nonzero information storage capacities
90 citations
TL;DR: In this article, two-by-two network arrays are implemented in these networks using a β reversing element and nested tree arrays of these elements may be used to synthesize rearrangeable switching networks which appear minimal.
Abstract: Rearrangeable switching networks are considered as permutation generators. Two-by-two network arrays may be implemented in these networks using a β reversing element. Nested tree arrays of these elements may be used to synthesize rearrangeable switching networks which appear minimal. Multistage network arrays of these elements may be implemented within a single coordinate device.
63 citations
TL;DR: In this article, the electron-beam accessed target in camera tubes for the Picturephone® visual telephone set has been fabricated and their properties evaluated, and the efficiency for conversion of incident photons to electrons in the read-out circuit has been expressed by the efficiency of the photometric readout circuit, which is achieved by oxidizing or by diffusing phosphorus into the light-receiving surface to reduce the surface-recombination velocity.
Abstract: Silicon diode arrays for use as the electron-beam accessed target in camera tubes for the Picturephone® visual telephone set have been fabricated and their properties evaluated. These targets offer significant advantages over the antimony trisulfide target commonly used in vidicon-type tubes. But there are certain potential limitations which must be dealt with in developing a silicon target. Three of its critical requirements are adequate sensitivity to visible light, low dark current, and junction uniformity and freedom from defects across at least 300,000 diodes per square centimeter. Sensitivity to visible light is expressed here by the efficiency for conversion of incident photons to electrons in the read-out circuit. Conversion efficiencies exceeding 50 percent in the visible region have been achieved by oxidizing or by diffusing phosphorus into the light-receiving surface to reduce the surface-recombination velocity. Diode leakage currents of ≦1 × 10−13 A per diode are required, and are obtained for target voltages up to about 5 to 7 V. Surface generated current dominates in the 8-μ diameter diodes of the array, but this component of current can be reduced substantially by use of (100) surfaces or by hydrogen annealing. Visible defects in a picture can result from leaky diodes or oxide pinholes which cause bright spots, and diodes covered by oxide which cause dark spots. Our best targets show a video display with only a few defects; processing must be improved to eliminate defects completely.
TL;DR: In this paper, a planar phased array of circular waveguides arranged in an equilateral triangular grid is analyzed, and the boundary value problem is formulated rather generally in terms of a vector two dimensional integral equation for an array of elements that are arranged in a doubly periodic grid along two skewed (nonorthogonal) coordinates.
Abstract: In this work, a planar phased array of circular waveguides arranged in an equilateral triangular grid is analyzed. The boundary value problem is first formulated rather generally in terms of a vector two dimensional integral equation for an array of elements that are arranged in a doubly periodic grid along two skewed (nonorthogonal) coordinates. Dielectric plugs, covers, and loading, as well as thin irises at the aperture, are accounted for in the formulation. Numerical solutions are obtained by using the Ritz-Galerkin method to solve the integral equation. Excellent agreement with experimental measurements using a waveguide simulator is observed. The existence of forced surface wave phenomena in equilateral triangular grid arrays and their strong dependence upon the mode of excitation is also demonstrated. These phenomena are shown to exist at isolated points in the scan coordinates. Reflection characteristics as well as the polarization characteristics of the radiation pattern are illustrated at selected planes of scan for both linear and circular polarization excitation.
TL;DR: Analysis and synthesis techniques make use of Z-transform methods in achieving the desired frequency response as the realization of an nth order difference equation, which makes the digital phase-locked loop ideally suited for use in large systems which use monolithic integrated circuits for microminiaturization.
Abstract: A method of synthesizing a general nth order phase-locked loop is presented In contrast to conventional phase-locked loops, the circuitry is digital rather than analog The general circuit consists of an assembly of logic blocks (gates and storage elements) which, when driven by external clock signals, exhibits phase-locked loop properties These properties, along with high stability and the absence of adjustments, make the digital phase-locked loop ideally suited for use in large systems which use monolithic integrated circuits for microminiaturization Analysis and synthesis techniques make use of Z-transform methods in achieving the desired frequency response as the realization of an nth order difference equation A general technique is developed and two specific cases, n = 1 and n = 2, are considered in detail Analytic results relating to the phase-locked loop's static and dynamic performance are derived and found to correlate well with laboratory results for actual circuits
TL;DR: In this article, an alternative approach which has been used to solve some practical problems by permitting dramatic step-size increases (for example, a factor of 104) is described in a way which provides some detailed understanding of why it is useful.
Abstract: In connection with the design of transistor circuits, for example, it is frequently necessary to obtain a numerical solution of a system of nonlinear ordinary differential equations. In some cases, these equations possess a property that leads to intolerable computational requirements relative to the use of standard predictor-corrector techniques or general linear multipoint formulas of open type. Here we describe an alternative approach which has been used to solve some practical problems by permitting dramatic step-size increases (for example, a factor of 104). The approach is developed in a way which provides some detailed understanding of why it is useful.
TL;DR: This paper presents a model which provides a reasonable approximation to observed error phenomena which is similar to the model developed by E. N. Gilbert, but several important modifications greatly simplify the estimation of parameters, and make the model correspond more closely to the physical phenomena involved.
Abstract: The nature of the errors in a regenerative digital transmission system is such that a memoryless channel is a poor model for predicting the error phenomena. In this paper we present a model which provides a reasonable approximation to observed error phenomena. The memory of the channel is represented by a Markov model. This model is similar to the model developed by E. N. Gilbert, but several important modifications greatly simplify the estimation of parameters, and make the model correspond more closely to the physical phenomena involved. Bounds for the channel capacity of the binary regenerative channel are obtained. Error separation, block error, and burst statistics are derived. Error model parameters are derived from available experimental data on the T1 digital transmission line and the switched telephone network. The Markov model is shown to provide a good representation of the observed error phenomena.
TL;DR: In this article, Bleistein and Ursell's work was combined and extended to obtain an asymptotic series which apparently holds over the entire range of the noncentral chi-square distribution, when the number of degrees of freedom becomes large, and the tails by a classical saddle point expansion.
Abstract: The noncentral chi-square distribution occurs in noise interference problems. When the number of degrees of freedom becomes large, the middle portion of the distribution is given by the central limit theorem, and the tails by a classical saddle point expansion. Here recent work by N. Bleistein and F. Ursell on “uniform” asymptotic expansions is combined and extended to obtain an asymptotic series which apparently holds over the entire range of the distribution. General methods for expanding saddle point integrals in uniform asymptotic series are discussed. Recurrence relations are given for the coefficients in two typical cases, (i) when there are two saddle points and (ii) when there is only one saddle point but it lies near a pole or a branch point.
TL;DR: In this article, the feasibility of using the YAG laser as a tool to thermally machine integrated circuits has been studied, and results suggest that defining the resistor geometry, trimming the resistors to value, fabricating gap capacitors, and defining interconnecting circuitry might be performed by such a laser.
Abstract: The feasibility of using the YAG laser as a tool to thermally machine integrated circuits has been studied. Results suggest that defining the resistor geometry, trimming the resistors to value, fabricating gap capacitors, and defining interconnecting circuitry might be performed by such a laser. Pattern generation by laser machining has been demonstrated on various thin and electroplated films. Vaporized lines (gaps) are readily attainable as fine as 0.25 mil in thin films and 0.4 mil in plated films. Much thinner lines may be obtained under particularly well-controlled conditions. These films may be removed with minimum effect to the substrate surface. The heat-affected region of the substrate may be confined to less than one film thickness. Better laser output control and shorter pulse widths will diminish this thickness. Gap capacitors have been made on sapphire substrates with capacitance approaching 20 pf in 0.04 square inches, and experiments suggest improvements. Tantalum films may be shaped to resistor geometries and trimmed to tolerance by removing metal or by oxidizing the resistive film with the laser. Resistors usually can be trimmed to tolerances of less than ±0.1 per cent. With further development it might be possible to combine these laser machining processes into a single-step, automated fabricating procedure for certain types of integrated circuits. We review some of the technical aspects of this and discuss using Q-spoiled YAG lasers to directly machine masks for photoetching.
TL;DR: This paper is concerned with the transmission of a discrete, independent letter information source over a discrete channel and a distortion function is defined between source output letters and decoder output letters.
Abstract: This paper is concerned with the transmission of a discrete, independent letter information source over a discrete channel A distortion function is defined between source output letters and decoder output letters and is used to measure the performance of the system for each transmission The coding block length is introduced as a variable and its influence upon the minimum attainable transmission distortion is investigated The lower bound to transmission distortion is found to converge to the distortion level d c (C is the channel capacity) algebraically as a/n The nonnegative coefficient a is a function of both the source and channel statistics, which are interrelated in such a way as to suggest the utility of this coefficient as a measure of “mismatch” between source and channel, the larger the mismatch the slower the approach of the lower bound to the asymptote d c For noiseless channels a = ∞ and for this case the lower bound is shown to converge to d c as a 1 (ln n)/n For noisy channels the upper bound to transmission distortion is found to converge to the asymptote d c algebraically as b[(ln n)/n]1/2 For noiseless channels, the upper bound converges to d c as a 1 (ln n)/n
TL;DR: These amplifiers were required to meet stringent specifications beyond the general scope of previous art, related to the simultaneous availability of relatively large output power, tight linearity, minimal delay distortion across a 40 per cent band, high input and output return loss, large dynamic range, and time stability.
Abstract: Two amplifiers, each covering a different band in the VHF range, were constructed for test set applications. These amplifiers were required to meet stringent specifications beyond the general scope of previous art. These specifications related to the simultaneous availability of relatively large output power, tight linearity, minimal delay distortion across a 40 per cent band, high input and output return loss, large dynamic range, and time stability. The performance problems were solved by using: (i) Quadrature couplers in a corporate structure array to provide a high multiplicity of “paralleled” transistors, yielding both the power and return loss capabilities. (ii) The emitter follower configuration as the basic amplifier element, providing broad band, high level performance owing to the large self degeneration of that configuration. (iii) A “feed-forward,” instead of a feedback, system for error control and noise cancellation.
TL;DR: A design for the terminal analog synthesizer is presented and the new features of this device are discussed and the method of converting from phonemes to control signals is discussed in detail.
Abstract: A new approach to speech synthesis by rule has been formulated and evaluated. A discrete set of symbols (phonemes and stress marks) is converted to a continuous acoustic waveform by a two-step transformation. The first step involves conversion from phonemes to control signals capable of driving a terminal analog speech synthesizer. The second step is conversion from control signals to the acoustic waveform. This paper presents a design for the terminal analog synthesizer and discusses the new features of this device. It discusses in detail the method of converting from phonemes to control signals. It places primary emphasis on determining the formant frequency control signals and the fundamental frequency contour, and presents models for determining these contours from the input data. The paper includes an experimental evaluation of the entire technique in terms of word intelligibility scores and consonant confusion matrices.
TL;DR: In this article, a preliminary study of a domestic satellite system is reported, and no attempt is made to relate system capacity to estimated needs; rather an effort has been made to conceive a system to carry the greatest possible amount of traffic.
Abstract: A preliminary study of a domestic satellite system is reported. Since the objective was to determine what might ultimately be possible, no attempt is made to relate system capacity to estimated needs; rather an effort has been made to conceive a system to carry the greatest possible amount of traffic. By making full use of modern rocket technology including the Saturn V class propulsion systems, highly directive multibeam antennas operating in the range from 15 to 40 GHz, interference resistant modulation methods, highly stabilized synchronous repeater platforms, and integrated solid state microwave repeater electronics, a very large communication capacity is obtained. For example, using 50 ground stations and 50 satellites operating in bands at 20 and 30 GHz, each 4 GHz wide, a total of 100 million voice circuits, or equivalent, can be provided.
TL;DR: This work considers the problem of the transmission of analog data from a Gaussian source over a memoryless channel with capacity C nats per second, and finds that the ideal error ∊2 0 is attainable in the limit as the coding delay N → ∞.
Abstract: We consider the problem of the transmission of analog data from a Gaussian source over a memoryless channel with capacity C nats per second. The source emits R independent zero mean Gaussian variates per second with variance σ2. These digits are block-coded RN at a time into N second channel inputs. The performance criterion is the mean square error. Let ∊2(N) be the smallest attainable mean square error with parameter N(R, C, σ2 fixed). Shannon has shown that ∊2(N) ≧ σ2 exp (−2C/R) ≜ ∊2 0 and ∊2(N) → ∊2 0 as N → ∞. Hence the ideal error ∊2 0 is attainable in the limit as the coding delay N → ∞. We are concerned with the rate at which ∊2(N) → ∊2 0 , and our principal result is that ∊2(N) — ∊2 0 ≦ O[(log N/N)1/2].
TL;DR: Factoring a matrix and multiplying successively by the factors can sometimes be used to speed up matrix multiplications.
Abstract: Factoring a matrix and multiplying successively by the factors can sometimes be used to speed up matrix multiplications. This is, in fact, the trick which creates the fantastic gains of the fast Fourier transform.
TL;DR: In this article, the nonlinear differential equation describing the receiver output is solved and explicit expressions obtained for the output signal, noise, and controlling second and third order distortions are presented for the case of a noise modulated FM input signal.
Abstract: The major components of an injection-locked-oscillator FM receiver are a linear mixer and a van der Pol type of negative resistance oscillator in a phase-locked configuration. In this paper the nonlinear differential equation describing the receiver output is solved and explicit expressions obtained for the output signal, noise, and controlling second and third order distortions. The input signal carrier is both amplitude and frequency modulated. Signal-to-distortion ratios have been computed and are presented for the case of a noise modulated FM input signal. The results indicate that excellent performance may be expected of such a receiver.
TL;DR: In this article, a method of computing bounds on the location of the solutions of resistive nonlinear electrical networks is given, and two iterative techniques are presented for computing the solutions.
Abstract: Several theorems are proved concerning the solutions of equations that arise in the study of resistive nonlinear electrical networks. The first, an existence and uniqueness theorem, applies to equations describing an interesting class of networks which includes certain active and nonreciprocal networks for which the existence and uniqueness of solutions has not previously been established. A method of computing bounds on the location of the solutions is given, and two iterative techniques are presented for computing the solutions. It is proved that the iterative techniques converge for a subclass of the equations which also includes equations describing certain active and nonreciprocal networks. Finally, the rate of convergence of the iterative techniques is compared with that of another well-known iterative technique and some practical computational aspects are pointed out. Computations for two example problems, not reported here, were carried out to show the practicality of applying these iterative techniques to the equations of specific networks.
TL;DR: An exact solution for the coupling effects between two waves with a particular complex periodic coupling function is presented; the particular coupling function gives the same wave interactions as constant coupling but at a translated value of differential phase constant as mentioned in this paper.
Abstract: An exact solution for the coupling effects between two waves with a particular complex periodic coupling function is presented; the particular coupling function gives the same wave interactions as constant coupling but at a translated value of differential phase constant. A transformation is given which permits known theory for constant coupling to be applied to the periodic coupling case. Approximate solutions are given for periodically reversed coupling (sinusoidal or square wave) between two waves, and calculations are presented which indicate the solutions are valid for arbitrarily long coupling regions or arbitrarily large integrated coupling strengths. The region of validity for earlier perturbation theory is defined and proved to include the cases of interest for multimode circular electric waveguides.
TL;DR: It is shown that many permutation alphabets provide energy per bit advantage over binary FSK, although the best results are obtained with one-out-of-N alphABets.
Abstract: Performance characteristics are derived for an FSK data transmission scheme in which M frequencies out of N are used simultaneously. Noncoherent matched filters are applied at the N frequencies, and the filter outputs are compared as in a permutation modulation system. It is shown that many permutation alphabets provide energy per bit advantage over binary FSK, although the best results are obtained with one-out-of-N alphabets. Considering bits per unit bandwidth, many permutation alphabets perform as well as or better than binary; however, one-out-of-N alphabets carry less information per unit bandwidth when N > 4.
TL;DR: In this article, the effects of dielectric slabs on the radiation characteristics of an infinite array of rectangular waveguides have been carried out, and it is found that the presence of such slabs can give rise to sharp resonant peaks in the reflection coefficient at certain scan angles.
Abstract: A further study of the effects of dielectric slabs on the radiation characteristics of an infinite array of rectangular waveguides has been carried out. It is found that, in addition to causing substantial and sometimes beneficial changes in the array performance, the presence of dielectric slabs can give rise to sharp resonant peaks in the reflection coefficient at certain scan angles. The occurrence of such resonant peaks at which total reflection occurs is contingent upon the presence of space harmonics which have surface-wavelike field distribution. Extensive data for both the H and E planes of scan, when the array is covered with a single slab, have been obtained and are presented here. This paper discusses the influence of the dielectric constant, slab thickness, and waveguide wall thickness on the resonant peak location, and points out the relationship between the resonance phenomenon and the surface wave propagation over a corrugated surface. It also presents some further results for the thin sheath and their extension to multiple sheaths.
TL;DR: In this paper, the authors used a coherent light beam to produce an electrical signal which corresponds to a scanned hologram, which was then used to reduce the spatial resolution required of the camera tube in a holographic television system by at least a factor of four.
Abstract: Several techniques are proposed in this paper which use a scanning coherent light beam to produce an electrical signal which corresponds to a scanned hologram. The hologram itself is not formed at the transmitting end of the system as a physical entity, rather the modulated electrical carrier frequency corresponding to the spatial carrier frequency of the hologram is generated by heterodyning. An advantage of the hologram heterodyne scanner is that it reduces the spatial resolution required of the camera tube in a holographic television system by at least a factor of four.
TL;DR: Computations of the distortion generated in passing large-index, frequency-modulated signals through symmetrical single-pole and three-pole bandpass filters are presented and the results are in good agreement with measurements.
Abstract: Computations of the distortion generated in passing large-index, frequency-modulated signals through symmetrical single-pole and three-pole bandpass filters are presented. The computation is for a bandlimited periodic modulation signal; noise modulation is simulated by the use of periodic noise samples in a Monte Carlo procedure. The convergence of the Monte Carlo procedure is illustrated for the case of the single-pole filter and the results are in good agreement with measurements. Computations of envelope distortion are also presented. These data give the amplitude-to-phase conversion in the receiver containing the filter to within a constant factor, the constant being the AM/PM conversion coefficient of the limiter.