This paper presents CMOS audio pre-amplifiers with integrated voltage regulators for digital electret microphones. Several techniques for achieving high input impedance and proper input bias, as well as methods for implementing very low-frequency integrated high-pass filtering are presented. The amplifier with integrated high-pass filter has 14.8dB of specified voltage gain, 200uA of current consumption from 2.4V-3.6V supply, 60dB of total harmonic distortion, and 72.8dB signal to noise ratio at 1Vpps and 1kHz output.

A local algorithm for smooth surface fitting for rectangular-grid data has been presented. It has the accuracy of a bicubic polynomial.

An algorithm for smooth surface fitting for scattered data has been presented. It has the accuracy of a cubic polynomial in most cases and is a local, triangle-based algorithm.

article Free Access Share on A method of univariate interpolation that has the accuracy of a third-degree polynomial Author: Hiroshi Akima U.S. National Telecommunications and Information Administration, U.S. Dept. of Commerce, Boulder, CO U.S. National Telecommunications and Information Administration, U.S. Dept. of Commerce, Boulder, COView Profile Authors Info & Claims ACM Transactions on Mathematical SoftwareVolume 17Issue 3Sept. 1991 pp 341–366https://doi.org/10.1145/114697.116810Published:01 September 1991Publication History 66citation1,251DownloadsMetricsTotal Citations66Total Downloads1,251Last 12 Months74Last 6 weeks6 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

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The articulation index (AI) described in CCIR Report 526 as a measure of voice intelligibility cannot adequately represent the effects of interfering signals on voice intelligibility. The minimum interference threshold (MINIT) described in the same report as a measure of voice transmission performance is not a performance measure.

A method of blvariate interpolation and smooth surface fitting is developed for z values given at points irregularly distributed in the x-y plane.The interpolating function is a fifth-degree polynomial in x and y defined in each triangular cell whmh has projections of three data points in the x-y plane as its vertexes.Each polynomial is determined by the given values of z and estimated values of partial derivatives at the vertexes of the triangle.Procedures for dividing the x-y plane into a number of triangles, for estimating partial derivatives at each data point, and for determining the polynomial in each triangle are described A simple example of the application of the proposed method is shown.

article Free AccessArtifacts AvailableArtifacts Evaluated & Reusable Share on Algorithm 526: Bivariate Interpolation and Smooth Surface Fitting for Irregularly Distributed Data Points [E1] Author: Hiroshi Akima U.S. Department of Commerce, NTIA, Institute for Telecommunication Sciences, Boulder, CO U.S. Department of Commerce, NTIA, Institute for Telecommunication Sciences, Boulder, COView Profile Authors Info & Claims ACM Transactions on Mathematical SoftwareVolume 4Issue 2June 1978 pp 160–164https://doi.org/10.1145/355780.355787Online:01 June 1978Publication History 54citation1,947DownloadsMetricsTotal Citations54Total Downloads1,947Last 12 Months27Last 6 weeks3 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

A binary noncoherent frequency-shift-keying (NCFSK) multiple-message one-shot radio transmission system is discussed where the receiver has no prior knowledge of the possible starting time of transmission. In this system each transmitted signal has a common preamble for signal acquisition and self-synchronization purposes. System design procedures are described for allowable frequency of occurrence of false alarm and probabilities of a miss and a message error specified for the system. In addition, the probability of premature response (i.e., the probability that the receiver makes an affirmative decision on acquisition of the signal when the sync preamble is only partially received) is taken into account. It is shown that the selection of sync preamble codes from randomly generated binary sequences can be a highly attractive approach. A simple, but very meaningful, criterion is suggested for aid in such a selection. The system described here can be used as a radio warning system and also as a selective call or selective interrogation system.

A statistical decision procedure for acquisition of a codedbinary noncoherent-frequency-shift-keyed (NCFSK) signal in a multiple-message one-shot transmission system is suggested. Performance of the system is also presented.

A new mathematical method is developed for interpolation from a given set of data points in a plane and for fitting a smooth curve to the points. This method is devised in such a way that the resultant curve will pass through the given points and will appear smooth and natural. It is based on a piecewise function composed of a set of polynomials, each of degree three, at most, and applicable to successive intervals of the given points. In this method, the slope of the curve is determined at each given point locally, and each polynomial representing a portion of the curve between a pair of given points is determined by the coordinates of and the slopes at the points. Comparison indicates that the curve obtained by this new method is closer to a manually drawn curve than those drawn by other mathematical methods.