Showing papers on "Filter (video) published in 1975"

STAR: An active biquadratic filter section

Abstract: This paper describes a thin-film hybrid integrated circuit (HIC) which is specifically manufactured to realize cascadable biquadratic active RC filter sections. The HIC consists of an RC network with one operational amplifier. This network is interconnected by a printed wiring board to realize Friend's Single Amplifier Biquad (SAB) and other filter sections. Design equations, components, predistortion method, and laser trimming are all discussed.

Cochlear Tuning Properties: Concurrent Basilar Membrane and Single Nerve Fiber Measurements

Abstract: Removal of perilymph from the cochlea has been reported to destroy the sharp tuning of cochlear neurons. That these changes are mechanical in origin is refuted by the concurrent recording of sharp neural tuning with broad basilar membrane responses from the same region of the partially drained cat cochlea. A second cochlear filter is therefore necessary.

A square root filter for real time multivariate regression.

Abstract: An algorithm is developed which makes it possible to perform multivariate regression in real time. The algorithm belongs into the class of square root filters and exhibits outstanding numerical characteristics, particularly in ill-conditioned problems. Because of these properties the algorithm is well suited for implementation in process computers and special digital devices operating with reduced word length.

Silicon photosensor with optical thin film filter

Abstract: Disclosed is silicon photodiode having a multilayer thin film optical filter deposited directly on the detecting surface thereof. The multilayer filter is an interference type filter designed to limit the normal response of a silicon photodiode so that its spectral response is essentially the same as that of the human eye. The multilayer filter is applied to the diode during fabrication using low cost mass production techniques. The multilayer filter materials are very durable and provide excellent passivation and environmental protection for the diode surface.

Solid state color imaging apparatus

Abstract: A solid state color imaging apparatus with a color encoding filter and a solid state area imaging device for producing a color signal representing an optical image of an object. The color filter is formed from a plurality of pairs of color filter strips arranged one above the other in a vertical scanning direction, each of which color filter strips consists of alternating transmissivity filter elements of two different colors. The color filter is placed on the imaging device so that each photosensitive element of the imaging device is covered with a corresponding filter element. During the self-scanning of the area imaging device, first and second signals which represent color difference signals are derived therefrom alternately in the successive scan lines, from which the color signal is produced.

Restoration of motion degraded images

Abstract: A new recursive procedure, based on state-space techniques and the use of a Kalman-Bucy filter is presented to solve the restoration problem of images degraded by motion in one direction. Both the noisefree and the noisy cases are considered.

Transmission line filter

Abstract: A transmission line filter having two conductors with insulation therebetween. A third conductor of a length related to the wavelength of the signal being filtered is spaced from one of the conductors but electrically coupled thereto. Terminal connectors are located at each end of the filter to interconnect the filter into the regular transmission line of the system in which the filter is being used. The filter can be formed of coaxial cable and can be a single frequency filter a multiple frequency filter of a bandpass filter arrangement. In a filter trap arrangement, one end of the third conductor is conductively connected to the other of the main conductors. A method for making a coaxial embodiment of the filter is achieved by initially placing the main line inner conductor together with the third conductor within the dielectric and subsequently chopping out sections of the third conductor line to adjust its length to the wavelength of the signal being filtered and to provide electrical connection to the outer shield which is subsequently placed over the dielectric. The filter provides unique application in controlling programs sent to subscribers in cable TV systems.

Blood filtering bag

Abstract: Disclosed is a blood filtering bag comprising a bag body provided with a blood inlet and a blood outlet, and a filter supported by a support member and dividing the bag body into two parts -- inlet side part and outlet side part. The support member is thermally fused to a peripheral portion of the bag body.

Self-calibratable spectrum analyzer

Abstract: A spectrum analyzer is disclosed which is of the type that utilizes an electrically scannable array of optical detectors. The array is selectively illuminated, i.e. irradiated, by at least two portions of a spectral band image of radiation. One of the portions is associated with a first spectral range and the other portion is associated with a second spectral range. The first and second ranges include mutually exclusive first and second spectral components, respectively, and a common third spectral component which is intermediate of the other two components. The detectors are calibrated by means which include a pair of optical filters. One of the filters is a single narow band transmission which has a transmission characteristic corresponding to one of the three aforementioned spectral components. The other filter is a double, i.e. two, narrow band transmission filter which has a transmission characteristic corresponding to the other two spectral components. In this way, the number of calibrating filters used in the system during the calibration mode is minimized and simplified than would otherwise be the case if a separate filter for each of the three spectral components were to be utilized.

Incandescent lamp with infrared filter

Abstract: The thermal radiation which is emitted by an electric incandescent lamp is eliminated according to the invention by providing an incandescent lamp with a filter which transmits visible light and which reflects infrared radiation, which filter consists of an interference filter and a heavily doped metal oxide filter which is disposed at the side of the interference filter which is remote from the filament body.

A New Type of Digital Filter for Data Transmission

Abstract: A digital filter is introduced consisting of a transversal part and a simple recursive network. The coefficients of the transversal part are equal to integer powers of two or zero; thus complicated multipliers are avoided and instead a simple routing circuit is used. Use of several types of the recursive network makes the filter applicable in different frequency ranges. The coefficients of the transversal part can be interpreted as differences of successive values of the impulse response of the filter. It is shown that this difference routing digital filter (DRDF) is especially suited for application in data transmission.

Modeling and Computer Simulation of a Microwave-to-DC Energy Conversion Element

Abstract: A microwave-to-dc energv conversion element consisting of a dipole antenna, a low-pass filter, a Schottky-barrier diode, and a dc filter has been modeled using a distributed transmission-line modeling technique that includes skin-effect losses. Computer simulation has shown 80-percent conversion efficiency and has indicated that the diode generates significant power at higher harmonics due to a resonance effect.

Filter for occupant restraint system fluid supply

Abstract: A filter assembly is provided for a cylindrical radial flow fluid supply having a combustible gas generator which is used to inflate a confinement for an occupant restraint system upon the occurrencee of a collision. The filter assembly includes a plurality of layers of filter material and support elements pressed to a densely packed flat form, rolled, closed, and inserted in the housing of the fluid supply adjacent the combustible gas generator.

Noncollinear tunable acousto-optic filter

Abstract: An electronically tunable optical filter is described wherein an optical beam is diffracted by an acoustic beam the group velocity of which is noncollinear with the optical beam transmitted through the birefringent crystal medium. The frequency and the direction of the phase velocity of the acoustic wave are chosen for a given incidence direction of the optical beam so that the diffraction occurs for a band of optical frequencies centered about a predetermined optical frequency and a relatively large angular distribution of incident optical beams. The noncollinear acousto-optic filter has the following advantages: (i) it allows very simple coupling of optical and acoustic beams into the interaction medium, (ii) it allows the use of multiple transducers for increasing tuning range or varying resolution, (iii) it allows a broad class of crystals to be used as filter material, (iv) it has a large degree of freedom in the filter design for optimizing efficiency or angular aperture and throughput, realizing narrow or broad optical passband and (v) it provides the spatial separation of incident and transmitted light through the filter and thus can be operated without the use of polarizers.

The treatment of bias in the square-root information filter/smoother

Abstract: The Dyer-McReynolds square-root information filter (SRIF) is rederived, using recursive least-square arguments. The result is applied to a system composed partly of biases. The filter sensitivity matrix, computed covariance, and consider covariance for this augmented system are reviewed. A new computationally attractive representation for the smoothed estimates, in terms of a smoothed sensitivity matrix and a smoothed computed covariance is presented.

Non-recursive digital filter employing simple coefficients

Abstract: A non-recursive digital filter is disclosed, composed of a cascaded plurality of basic sections, each of which is characterized by coefficient values of integer powers of two's. No hardware multipliers are required in the filter and the operating speed is several times faster than other filters which utilize multipliers.

In-line filter for gases

Abstract: Apparatus for removing moisture such as oil and water vapor from compressed gases such as air with less decrease in pressure by conventional filter means by providing a relatively coarse annular filter to condense the major portion of such moisture by gases passing downward therethrough to afford drainage of condensate by gravity before the gases pass upward through coaxial interior desiccant filter means to remove any residual moisture before the moisture free gases are discharged from the upper end of the desiccant filter means. The coarse filter is contained between transparent outer and inner containers and the desiccant filter means is contained within the transparent inner container so as to extend upwardly above the upper end of the coarse filter such that the condition of both the coarse filter and desiccant filter means is visually observable.

Parenteral liquid administration set with non-air blocking filter

Abstract: A parenteral liquid administration set is provided which comprises flexible tubing, connection means with a parenteral liquid source at one end of the tubing, and means for connection to a blood vessel-penetrating member, such as a needle, at the other end of the tubing. In accordance with this invention, a filter, positioned in fluid communication with the bore of the tubing, comprises a housing, which carries first and second filter members in parallel flow position so that each increment of fluid flow through the tubing passes through one or the other of the filter members. The first filter member is hydrophilic, to permit the passage of solution under normal administration conditions. The second filter member is hydrophobic, to permit the passage of gas after wetting of the filter members. Accordingly, the filter members, which are closed from the exterior by the administration set, cannot airblock by the accumulation of air bubbles immediately upstream of the filter members.

Molded waveguide filter with integral tuning posts

Abstract: A molded plastic waveguide filter having a substantially U-shaped filter body with integral tuning posts shorter than the walls thereof and a substantially flat filter cap affixed to the walls of the filter body.

Millimeter waveguide to microstrip transition

Abstract: A waveguide to microstrip transition apparatus in which a waveguide coupledo a microstrip circuit is provided with a mode filter for suppressing spurious modes of electromagnetic signal propagation. The mode filter is attached to the end of the waveguide that is coupled to the microstrip circuit and the mode filter extends over a portion of the microstrip circuit.

The application of an approximate non-linear filter to systems governed by coupled ordinary and partial differential equations

Abstract: An approximate non-linear filter is applied to systems described by coupled ordinary and partial differential equations with both volume and boundary disturbances and measurement errors. Measurements are assumed to be carried out at u discrete number of spatial positions in the distributed portion of the system. The filter is applicable to cases in which the data are available continuously in time and at discrete sampling instants. Both versions of the filter are applied to an ingot heating problem of some interest in steel-making. The numerical results show that the filter is rapidly convergent and quite robust.

Electrically tunable narrowband optical filter

Abstract: A narrowband optical filter of the Sole type is made from a twisted stack of birefringent plates between polarisers. If the plates are replaced by homogeneously aligned liquid-crystal cells whose retardation is controllable, the transmitted wavelength of the filter can be varied over the visible spectrum. The characteristics of a rudimentary device of this type agree with predictions.

Air filter cleaner

Abstract: An air filter cleaner is disclosed which is portable and which may be used on the job site for the cleaning of air filters of heavy construction equipment. The air filter cleaner is lightweight and may easily be carried or moved by a single person. The filter is comprised of a base member and an upper member. The filter to be cleaned is inserted between the base member and the upper member. The upper member is provided with a vertically depending rotatable pipe means provided with radially directed nozzles. The pipe means is also provided with a pair of nozzles directed at an angle to the radial to provide a rotary movement to the pipe means. The air filter cleaner may be operated from air compressors readily available on the job site, such as compressors on the heavy construction equipment itself, during normally scheduled down times such as lunch hours. The purpose of the above abstract is to provide a nonlegal technical statement of the disclosure of the contents of the instant patent application and thus serve as a searching-scanning tool for scientists, engineers and researchers. Accordingly, this abstract is not intended to be used in understanding or otherwise comprehending the principles of the present invention hereinafter described in detail, nor is it intended to be used in interpreting or in any way limiting the scope or fair meaning of the claims appended hereto.

Method and apparatus for cleaning filter means

Abstract: A filter assembly for use in dust control apparatus wherein the filter assembly employs filter barrier material suspended between opposed end frame means. In order to remove accumulated solids from the filter, stroking means, such as a cam-cam follower arrangement or a rotary eccentric loading arrrangement are operatively coupled to the filter assembly to impart reciprocatory stroking motion to one of said opposed frame means and accordingly to the filter material. The length and frequency of stroking motion is selected so as to provide parametric resonant vibration to the filter material through alternate relaxation and tension generated along the length of the material.

Controlled capacitive filter for active loads

Abstract: A single phase controlled capacitive filter with a smaller, more efficiently used filter capacitor than conventional capacitive filters is connected between rectifier terminals and supplies voltage to an active load producing dc output voltage. The charge and discharge intervals of the filter capacitor are controlled by gate controlled thyristors or other devices such that discharge occurs when the instantaneous rectified line voltage falls below the dc output voltage. The filter capacitor during discharge is placed in series with the load or can remain in parallel with the load in a simpler arrangement.

Method of and apparatus for cleaning filter boxes

Abstract: In a filter box a first air flow generating unit drives air, containing solid impurities, through a filter disposed upstream of said unit. Without interrupting the drawing of impure air into the filter box, the filter is periodically cleaned by drawing auxiliary air through the clean side of the filter by a second air flow generating unit for dislodging and carrying away impurities accumulated on the work side of the filter. The drawing of impure air into the filter box is effected by the second air flow generating unit during the periodic cleaning operation.

Design and evaluation of shifted-companion-form active filters

Abstract: Two techniques for designing a class of low-sensitivity, follow-the-leader, feedback-type active filters have been introduced by Hurtig and Laker-Ghausi. The FLF configuration consists of a cascade of second-and/or first-order sections, with feedback from each section back to the first. This paper presents an approach for designing FLF-type realization for all classes of filter functions. The technique is based on a shifted-companion form of the associated-state equations. Some salient features of Hurtig's primary resonator block, Laker-Ghausi's follow-the-leader feedback, and the shifted-companion-form techniques are presented below. (i) Hurtig's PRB realizes any all-pole (no finite transmission zeros) filter function. This includes the low-pass, high-pass, and symmetrical bandpass filters without finite zeros. Explicit design equations are available, and the individual sections in the array are identical. (ii) Laker-Ghausi's FLF realizes any symmetrical (including finite transmission zeros) bandpass filter function. The sections are not constrained to be identical, which allows optimization using this degree of freedom. Finite zeros are realized by a summation technique. (iii) The SCF realizes all types of filter functions, i.e., low-pass, high-pass, bandpass, all-pass, or band-reject filters. Explicit design equations are available. The first section can differ from the rest, thus allowing some optimization with standardization. Feed-forward as well as summation techniques can be used to realise the finite zeros. Two bandpass design examples using SCF, PRB, and/or Laker-Ghausi FLF techniques are given and compared with the low-sensitivity coupled (leapfrog) biquad, the conventional cascade biquad, and the passive ladder filter designs. The comparison shows that the passive filter gives