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IEEE Transactions on Audio and Electroacoustics

Issue 1 • Date March 1971

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Displaying Results 1 - 20 of 20
  • [Front cover and table of contents]

    Publication Year: 1971, Page(s): 0
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1971, Page(s): c4
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    Freely Available from IEEE
  • Directional transducers

    Publication Year: 1971, Page(s):19 - 23
    Cited by:  Papers (3)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    Directional electroacoustic transducers for the audio-frequency range, based on the electrostatic principle using foil electrets, have been designed. The directivity is achieved by utilizing first, second, and higher order gradients with bidirectional, unidirectional, and toroidal characteristics. Experimental results on directional characteristics directivity factor, and frequency response for ea... View full abstract»

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  • Digital filters with equiripple or minimax responses

    Publication Year: 1971, Page(s):87 - 93
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    Techniques for determining the coefficients of digital filters which have equiripple or minimax errors are reviewed and occasionally extended. These techniques include: 1) mapping to provide equiripple errors in recursive filters; 2) windows for making Fourier spectrum measurements with minimax leakage; 3) the simplex method of linear programming to provide minimax errors in a nonrecursive filter'... View full abstract»

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  • Use of solid-state acoustic transducers in communications

    Publication Year: 1971, Page(s):13 - 18
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (784 KB)

    Semiconductor and solid-state devices have been used extensively to measure and generate stresses and stress waves in solids, liquids, and gases. Semiconductor devices have been used as strain gauges to measure strains and to respond to acoustic pressures, p-type silicon has a gauge factor of over 100 times that of a metallic strain gauge. By using the amplifying regimes of Esaki diodes and transi... View full abstract»

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  • Exact second-order bandpass digital filters

    Publication Year: 1971, Page(s):104 - 106
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    Exact expressions for the sine and tangent forms of the second-order digital Butterworth bandpass filters are given. Here "exact" means that the placement of the half-power points is precise. These results are then used to generate exact forms of the band reject filters. View full abstract»

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  • The application of digital filters for moving target indication

    Publication Year: 1971, Page(s):72 - 77
    Cited by:  Papers (1)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    A digital system is proposed which detects moving targets and suppresses the reflections of stationary targets in a pulse radar. The system uses the quantized coherent video for the spectral discrimination of Doppler shifted signals. The main part is a recursive-type digital filter. Quadrature channels are used in order to improve the detectability of signals. The part which follows it is an integ... View full abstract»

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  • A digital frequency synthesizer

    Publication Year: 1971, Page(s):48 - 57
    Cited by:  Papers (289)  |  Patents (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1152 KB)

    A digital frequency synthesizer has been designed and constructed based on generating digital samples of \exp [j(2^{\pi}nk/N)] at time nT . The real and imaginary parts of this exponential form samples of quadrature sinusoids where the frequency index k is allowed to vary View full abstract»

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  • The use of in-flight manikin recordings for evaluating the communication effectiveness of flight helmets

    Publication Year: 1971, Page(s):97 - 102
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (904 KB)

    An exploratory study has been conducted to determine the feasibility of obtaining and using in-flight manikin recordings to evaluate flight helmets with respect to speech intelligibility. Intelligibility test materials were transmitted to six airborne subjects and a manikin as each was fitted with different flight helmets. Similar test materials were presented to the same six subjects in a simulat... View full abstract»

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  • Computer-generated spectrogram displays for on-line speech research

    Publication Year: 1971, Page(s):44 - 47
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (904 KB)

    A program to generate and display spectrograms on a computer-controlled scanned-display television monitor is described. The program features computation of power spectra for selected time segments with the aid of the fast Fourier transform algorithm, four-level intensity quantization controlled by a threshold under operator control, and flicker-free scanned display of the generated data. The comp... View full abstract»

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  • Problems in realizing a digital vocoder and novel solutions

    Publication Year: 1971, Page(s):94 - 96
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    Some details are given of a channel vocoder intended for use as a speech output device for data-processing systems, but also suitable for voice transmission with 2400 bit/s, e.g., in narrow-band digital radio systems or in digital encryption systems. Characteristic features are, in the analyzer, the use of switched op-amp integrators instead of conventional low-pass filters plus rectifiers, and di... View full abstract»

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  • Multidimensional complex BIFORE transform

    Publication Year: 1971, Page(s):106 - 107
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (160 KB)

    Complex BIFORE transform (CBT) is extended to multiple dimensions. Basic properties of multidimensional CBT are developed and a fast algorithm for its computation is applied. View full abstract»

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  • Root and delay parameters for normalized Bessel and Butterworth low-pass transfer functions

    Publication Year: 1971, Page(s):64 - 71
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Tables are given for the roots of the normalized low-pass Bessel and Butterworth transfer functions in both Cartesian and polar form. The latter form is especially useful when designing transitional (Butterworth-Thomson) functions. The tables cover the orders 1 through 30 inclusive. In addition, the group delay characteristics for each of the above orders are tabulated for both the Bessel and Butt... View full abstract»

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  • The Fourier transform of spline-function approximations to continuous data

    Publication Year: 1971, Page(s):103 - 104
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    The transform of a spline-function approximation to continuous data is called a spline transform. In this correspondence, the spline and the discrete Fourier transforms (DFT) are compared as means for numerical computation of the Fourier integral transform. It is shown how the spline transform reduces errors introduced by the discrete transform and alleviates noise problems when the sampling rate ... View full abstract»

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  • Statistical methods for investigating phase relations in stationary stochastic processes

    Publication Year: 1971, Page(s):78 - 86
    Cited by:  Papers (59)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (984 KB)

    Harmonically related peaks in the spectrum of a stationary stochastic process may indicate the presence or wave components that are not sine-shaped, i.e., whose Fourier expansions contain phase-locked higher order terms. But the spectrum itself suppresses phase relations, and more refined methods are needed to decide such questions. Moreover, phase relations might also exist outside of the peaks. ... View full abstract»

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  • On maximally flat sharp cutoff low-pass filters

    Publication Year: 1971, Page(s):58 - 63
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    Maximally flat (MF) low-pass filters with multiple pairs of coincident or distinct imaginary axis zeros are investigated and compared with the all pole Butterworth filters. It is shown that for the same order n , finite zero filters provide much sharper cutoff than Butterworth filters, and that the cutoff slope increases with increasing number of zeros. Express... View full abstract»

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  • Electret transducers applied to the telephone

    Publication Year: 1971, Page(s):1 - 5
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    Successful application of electrets as telephone transmitter and less successful application as receivers are discussed. Amplifier gain and maximum input noise are derived from electret performance and system requirements. Simple corona charging is sufficient to produce stable fluorocarbon electrets with a useful life from 10 to 20 years. Two design approaches to compensate slackening of the elect... View full abstract»

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  • Spectral estimates from nonuniform samples

    Publication Year: 1971, Page(s):24 - 31
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (768 KB)

    Errors in power spectral density estimates are analyzed for a problem in which the estimator processes nonuniformly spaced data samples as if they were uniformly spaced (e.g., via fast Fourier transform). The sample position errors, or jitter, are thought to be the result of fluctuations in the spacings between the sampling positions. One application of this model is to samples taken from a magnet... View full abstract»

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  • Flexure mode piezoelectric transducers

    Publication Year: 1971, Page(s):6 - 12
    Cited by:  Papers (21)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    Although flexurally responsive piezoelectric elements have been utilized for a few decades, interest in their utility remains high. This is a result of the ability of such structures to generate high output from sources of low mechanical impedance, or conversely, to develop large displacement at low levels of electrical excitation. Typically, a bending response is obtained from a sandwich-like str... View full abstract»

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  • A scheme for speech processing in automatic speaker verification

    Publication Year: 1971, Page(s):32 - 43
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1480 KB)

    Experiments investigating adaptive pattern recognition in automatic speaker verification are reported. A binary decision confirming or rejecting a speaker's purported identity is required. The experiments involve 7000 phrase length utterances of 118 speakers. An average misclassification rate of one percent with a "no decision" rate of ten percent is obtained. Other experiments indicate that the u... View full abstract»

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Aims & Scope

This Transactions ceased production in 1973. The current retitled publication is IEEE Transactions on Signal Processing.

Full Aims & Scope