Showing papers on "Filter (video) published in 1983"

Suction canister with unitary shut-off valve and filter features

Abstract: A suction canister assembly comprises an enclosed receptacle having a first opening for providing suction to the receptacle and a second opening for drawing fluids, including liquids and gases, into the receptacle during suction. A unitary shut-off valve/filter element is associated with the interior side of the first opening. This element is oriented within the receptacle so as to be contacted by liquid in the receptacle which rises therein. The element is porous and is adapted to filter particulate matter from gas passing therethrough. In addition, the valve/filter element is capable of developing sufficiently high surface tension under liquid contact to serve as a barrier against liquid passage therethrough at pressure differentials across the element when vacuum is applied on one side of the element. As a result, the element is adapted to terminate suction through the suction opening when liquid rises in the receptacle to completely cover the element.

Polyphase quadrature filters--A new subband coding technique

Abstract: A new method of implementing filter banks for subband coding of speech is presented. First, Esteban's Quadrature Mirror Filter principle is extended to allow the direct synthesis of filter banks with any number of equal size filter bands. Then, by combining the quadrature filter characteristic with the polyphase network implementation of filter banks, a new filter bank structure is obtained which requires 35% fewer computations than existing designs. In this paper the theory of operation of the Polyphase Quadrature Filter is presented and techniques for its efficient implementation are described. Then, examples of filter banks using this approach are shown and compared with other designs, and a simulation of a 16 Kbits/s coder using these filters is presented.

Mel Log Spectrum Approximation (MLSA) filter for speech synthesis

Abstract: The spectral envelope of speech can be represented efficiently by the log magnitude spectrum on the nonlinear frequency scale, which is close to mel scale (called mel-log spectrum). the mel cepstrum defined by its Fourier coefficients is also considered to have a suitable property as the parameter to represent the spectral envelope. So far, no satisfactory filter has been reported for the synthesis approximating the mel-log spectrum. This paper presents a method of constructing the mel-log spectrum approximation (MLSA) filter, which has a relatively simple structure and a low coefficient sensitivity, together with a design example of MLSA filter for speech synthesis. the transfer function of MLSA filter is represented by Pade approximation, which approximates the exponential of the transfer function of the filter (so-called basic filter). Since the transfer function of the basic filter is represented by a polynomial with the transfer function of the first-order all-pass filter as the variable, it is necessary in the realization of the filter to delete from the feedback loop the path without a delay. By the construction method of MLSA filter shown in this paper, the path without delay can easily be deleted from the feedback loop in the MLSA filter. the obtained MLSA filter is of relatively simple structure and has low coefficient sensitivity. the quantization characteristics of the coefficient are also satisfactory.

Quasi-optical waveguide filter

Abstract: A waveguide filter particularly well suited for use in the millimeter and submillimeter wavelength range of the spectrum. The filter includes a number of uniformly spaced gratings installed in a waveguide section and having grating strip patterns contoured to conform with a selected waveguide mode, such as the circular TE11 mode. The gratings are angularly oriented in the manner of a free-space plane-wave quasi-optical filter and provide similar desired frequency characteristics, but without the disadvantages of large size and the need for planewave launchers.

A second look at bloom filters

Abstract: This note deals with a paper by Gremillion demonstrating the simulation approach to the design of a Bloom filter. It is shown that an analytical approach can yield insights into competing filter design and give expected values for the goodness-of-hash transformations not available with simulation. On the other hand, simulation gives insight into what can be expected with available hash transformation not available from an analytic approach.

On the effects of varying filter bank parameters on isolated word recognition

Abstract: The vast majority of commercially available isolated word recognizers use a filter bank analysis as the front end processing for recognition. It is not well understood how the parameters of different filter banks (e.g., number of filters, types of filters, filter spacing, etc.) affect recognizer performance. In this paper we present results of performance evaluation of several types of filter bank analyzers in a speaker trained isolated word recognition test using dialed-up telephone line recordings. We have studied both DFT (discrete Fourier transform) and direct form implementations of the filter banks. We have also considered uniform and nonuniform filter spacings. The results indicate that the best performance (highest word accuracy) is obtained by both a 15-channel uniform filter bank and a 13-channel nonuniform filter bank (with channels spacing along a critical band scale). The performance of a 7-channel critical band filter bank is almost as good as that of the two best filter banks. In comparison to a conventional linear predictive coding (LPC) word recognizer, the performance of the best filter bank recognizers was, on average, several percent worse than that of an eighth-order LPC-based recognizer. A discussion as to why some filter banks performed better than others, and why the LPC-based system did the best, is given in this paper.

Microporous filter system and process

Abstract: A microporous filter system comprises two types of hydrophilic, microporous filter media operating in series. The two filter media have opposite zeta potentials with the upstream or first filter medium preferably having the positive zeta potential and the downstream or second filter having the negative zeta potential. The first filter medium typically has an absolute pore rating of from about 0.1 to about 1.0 micrometer and the second or downstream filter medium typically has an absolute pore rating of from about 0.02 to about 0.1 micrometer. The downstream or second filter has a finer absolute pore rating than the upstream or first filter. Fluids contaminated with ultrafine particles can be purified with an essentially absolute efficiency to remove 99.99 percent or more of the particulate matter in the contaminated fluid. The filter system finds particular use in the preparation of ultrapure effluent water of near theoretical resistivity and in the removal of bacteria and endotoxins to form sterile fluids.

Encoding pattern for single chip CCD camera processing scheme

Abstract: A color filter is provided for use with an imager which has a plurality of discrete collection sites. The filter has a plurality of color filter elements arranged in rows aligned with the collection sites. Two elements of the filter overlay a scan line of the imager in one television field, and each of the rows has a repeating sequence, e.g., 6, of at least two independent colors. The adjacent rows in the filter have their color sequences shifted by two elements. A demultiplexing scheme is disclosed, which features a high-frequency luminance signal having a constant colorimetric composition.

Design of Interdigitated Capacitors and Their Application to Gallium Arsenide Monolithic Filters

Abstract: Theoretical expressions for the interelectrode capacitance and conductor losses for an array of microstrip transmission lines are presented. The effect of finite conductor thickness is included in the analysis by introducing equations for the effective width of the transmission lines. Good agreement between theory and experiment is observed up to 18 GHz. Experimental results obtained from a lumped-element GaAs monolithic bandpass filter are in excellent agreement with theory. The filter has 1.5-dB insertion loss at 11.95 GHz and greater than 22-dB loss in the stopband. The filter measures 0.58x 1.3x0.203 mm.

Automatic time domain equalization of audio signals

Abstract: This disclosure concerns an equalizer for an audio reproduction system in which equalization is achieved using a discrete time filter. The filter is preferably implemented with a microprocessor programmed for generating and storing the filter coefficients in accordance with a perceived acoustic test signal reproduced by the system. Following generation and storage of the coefficients, the microprocessor also serves to equalize an input audio signal by convolving the stored coefficients with digitized time samples of the audio input signal.

Two-sided linear filter identification

Abstract: It is argued that there are a number of situations in life science where it is desirable to attempt a two-sided linear filter identification. A simple method is presented for the determination of a nonparametric, two-sided linear filter from system input and output data. The time-domain filter is determined from a matrix equation involving the input autocorrelation function and the two-sided cross-correlation function. The resulting filter minimises the sum of squared differences between the actual and predicted outputs.

Remote telemetry unit

Abstract: A remote-telemetry unit for monitoring and reporting to a remote location over a telephone line the condition of an associated piece of equipment at predetermined times, when polled and when the equipment condition dictates, the unit including a direct access arrangement, a switched-frequency Friend Biquad type filter and a detector, the combination for detecting tone signals developed on the line, and a digital-to-analog converter and a controller, in combination with the direct access arrangement for developing on the line tone signals for dialing and for condition reporting.

Adaptor for external oil filter

Abstract: A seal containing cast adaptor member having inlet and outlet ports for hose coupling to an externally mounted disposable cartridge-type oil filter. The housing thus permits the engine's conversion from a conventional often inaccessibly placed spin-off filter or smaller replaceable cartridge filter to a larger capacity, externally mounted filter.

Energy subtraction processing method for radiation images, stimulable phosphor sheet, stimulable phosphor sheet composite member and stimulable phosphor sheet-filter composite member used for the method

Abstract: As an X-ray detecting means in an energy subtraction processing method, there is used a composite member comprising a plurality of stimulable phosphor sheets exhibiting different levels of characteristics of absorbing the low energy component of a radiation and overlaid one upon another, or a composite member comprising a plurality of stimulable phosphor sheets and at least one filter made of a material absorbing the low energy component of a radiation which are overlaid one upon another, or a stimulable phosphor sheet comprising a substrate made of a material absorbing the low energy component of a radiation and stimulable phosphor layers provided thereon. The composite member or the stimulable phosphor sheet is exposed to a radiation passing through an object including a specific structure to record therein at least two radiation images between which the image information at the portion of the specific structure is different. On the basis of the radiation images read out from the composite member or the stimulable phosphor sheet, a subtraction image is obtained.

Tunable active filter

Abstract: A tunable high-pass or low-pass filter employs a balanced amplifier (Fig. 3, 30) having electronically controlled resistance elements (39, 40) in either two input (31, 32) or two feedback (35, 36) paths (or both). A reactive element (41, 42) is placed in each of the other pair of paths. Especially low distortion results from this arrangement, allowing convenient integrated circuit implementation with a nonlinear device (e.g., MOS transistor) as a voltage-controllable element. Multiple stages can be cascaded and controlled from a reference clock (Fig. 1) or other precision source for high accuracy (Fig. 3).

Water filtration process and apparatus having upflow filter with buoyant filter media and downflow filter with nonbuoyant filter media

Abstract: High rate filtration system includes an upflow filter vessel containing a bed of buoyant media followed by a downflow filter vessel containing a bed of nonbuoyant media. The upflow filter vessel is unobstructed by cross-sectional, media-confining screens. A horizontal trough structure collects filter effluent and makes it possible to clean the bed by diffusing air into the liquid below the bed so that average fluid density in the bed is reduced. The reduction in fluid density results in expansion of the bed as media particles descend by gravity.

Electronic air filter

Abstract: This invention provides an improved electronic air filter comprising fibrous material such as glass fibers which are polarized by insulated screens. The screens are charged with high voltage provided by a power supply which is an integral part of the filter unit. This arrangement provides a filter with extremely low ozone emission.

Self-cleaning air filter

Abstract: An improved self-cleaning air filter (2) of the pulse jet type. The filter includes at least one filter element (20) located in a dirty air plenum (6) which is separated from a clean air plenum (8). A valve (64) directs a cleaning jet of gas that moves in a back flow direction along the filter element to remove accumulated contaminants therefrom. A diffuser is located in the clean air plenum for diffusing the cleaning jet of gas to convert the cleaning jet to a high volume, low pressure jet which substantially fills the entire cross-sectional area of the filter element. The filter element is releasably contained inside the dirty air plenum on elongated support members (36). Rotatable cams (44) are provided for laterally shifting the filter element to lock the filter element in place against a dividing wall (10).

Speaker-independent word recognizer

Abstract: Speaker-independent word recognition is performed, based on a small acoustically distinct vocabulary, with minimal hardware requirements. After a simple preconditioning filter, the zero crossing intervals of the input speech are measured and sorted by duration, to provide a rough measure of the frequency distribution within each input frame. The distribution of zero crossing intervals is transformed into a binary feature vector, which is compared with each reference template using a modified Hamming distance measure. A dynamic time warping algorithm is used to permit recognition of various speaker rates, and to economize on the reference template storage requirements. A mask vector with each reference vector on a template is used to ignore insignificant (or speaker-dependent) features of the words detected.

Intercomputer communications based on message broadcasting with receiver selection

Abstract: An apparatus and method of intercomputer communications based on message broadcast with receiver selection is taught. A distributed computer system is described in which each computing element includes a hardware message filter which provides content tag recognition and selection. The overall system architecture allows software modularity and both hardware and software extensibility. The message filter can be preset or dynamically programmed, and can be operated in conjunction with a serial or parallel broadcast bus.

E-Plane Filters with Finite-Thickness Septa

Abstract: The effect of the metalization thickness of the septum is incorporated into an efficient computer-aided design (CAD) program for E-plane filters. The method is mathematically exact and numerically efficient. The results agree well with experimental data. The effect of the metal thickness on filter performance is demonstrated with a Ku-band filter.

Millimeter Wave Printed Circuit Spurline Filters

Abstract: This paper provides a new equivalent circuit model for a spurline filter section in an inhomogeneous coupled-line medium whose even and odd mode phase velocities are unequal. This equivalent circuit permits the exact filter synthesis to be performed easily. Millimeter-wave filters at 26 to 40 GHz and 75 to 110 GHz have been fabricated using the model, and experimental results are included which validate the equivalent circuit model.

Analytical Steady State Solution for a Kalman Tracking Filter

Abstract: Analytical expressions are given for the steady state solution to a Kalman tracking filter used in a track-while-scan radar system. The radar sensor measures range and range rate, and both these measurements are utilized in the filter. The solution for range measurements only is obtained as a special case. Graphs are also given which show how the solution depends on different parameters.

Polyacrylic acid/chitosan polyelectrolyte complex

Abstract: A novel composition of matter comprising a polyacrylic acid/chitosan complex. This complex is particularly useful as a membrane or filter.

Frequency multiplexed optical spatial filter

Abstract: A frequency multiplexed optical spatial filter comprises a thin film of a photochemical hole burning material. The filter stores a plurality of images in the photochemical hole burning medium. The images are formed at different optical frequencies and coexist in the same volume of the storage medium. Individual images are accessed by changing the frequency of the illuminating radiation.

Application of multiple model estimation to a recursive terrain height correlation system

Abstract: This paper describes the results of an investigation of the performance capabilities of an extended Kalman filter (EKF)-based recursive terrain correlation system proposed for low-altitude helicopter navigation. The major disadvantage of this concept is its sensitivity to initial position error. One method for reducing this sensitivity, involves the use of multiple model estimation techniques. In the multiple model approach, a bank of identical EKF's, each of which is initialized at a different point in the a priori uncertainty basket, is employed to ensure that one filter is initialized near the true aircraft position. In this manner, the probability of filter convergence is increased substantially, leading to improved navigation performance.