Showing papers on "Filter (video) published in 1992"

Multirate Systems and Filter Banks

Abstract: 1. Introduction 2. Review of Discrete-Time Systems 3. Review of Digital Filters 4. Fundamentals of Multirate Systems 5. Maximally Decimated Filter Banks 6. Paraunitary Perfect Reconstruction Filter Banks 7. Linear Phase Perfect Reconstruction QMF Banks 8. Cosine Modulated Filter Banks 9. Finite Word Length Effects 10. Multirate Filter Bank Theory and Related Topics 11. The Wavelet Transform and Relation to Multirate Filter Banks 12. Multidimensional Multirate Systems 13. Review of Discrete-Time Multi-Input Multi-Output LTI Systems 14. Paraunitary and Lossless Systems Appendices Bibliography Index

Nonseparable multidimensional perfect reconstruction filter banks and wavelet bases for R/sup n/

Abstract: New results on multidimensional filter banks and their connection to multidimensional nonseparable wavelets are presented. Among the topics discussed are sampling in multiple dimensions, multidimensional perfect reconstruction filter banks, the two-channel case in multiple dimensions, the synthesis of multidimensional filter banks, and the design of compactly supported wavelets. >

Tutorial survey of composite filter designs for optical correlators.

Abstract: A tutorial survey is presented of the many composite filter designs proposed for distortion-invariant optical pattern recognition. Remarks are made throughout regarding areas for further investigation.

High efficiency power factor correction using interleaving techniques

Abstract: A highly efficient 1.5 kW power factor correction converter for computer applications is presented. Eight boost-topology switching cells are interleaved to meet stringent EMI input ripple specifications while operating at a very low switching frequency (25 kHz per cell) to minimize switching losses. The result is a system with very high conversion efficiency (94%-97%, including input bridge, bias supply, and EMI filter losses) over the 93-264 VAC input range. Key implementation details, including discontinuous inductor current operation, a combination of linear and bang-bang control algorithms for fast dynamic load response, and extended (100 ms) power outage ride-through capability, are described. >

Simulation of 3-D random rough surface by 2-D digital filter and fourier analysis

Abstract: 2-D FIR filters are applied to the generation of 3-D random surfaces in this paper. The circularly symmetric low-pass filters are firstly employed to generate the isotropic random surfaces with no restrictions on the shape of ACF. To simulate real rough surfaces, however, one has to generate the surfaces having an expected autocorrelation function and height distribution, which requires determining the filter coefficients corresponding to the specified ACF. A spectrum analysis approach is developed in this paper to compute the filter coefficients and the FFT procedure provides an efficient way to implement the filter. The Johnson translator system of distribution is introduced into the generation procedure of non-Gaussian surface with a required ACF. The analysis indicates that the 2-D FIR filters used in this paper are mathematically identical with the 2-D MA time series model which simulates the ACF within whole correlation regions.

Wiring considerations in analog VLSI systems, with application to field-programmable networks

Abstract: This thesis develops a theoretical model for the wiring complexity of wide classes of systems, relating the degree of connectivity of a circuit to the dimensionality of its interconnect technology. This model is used to design an efficient, hierarchical interconnection network capable of accommodating large classes of circuits. Predesigned circuit elements can be incorporated into this hierarchy, permitting semi-customization for particular classes of systems (e.g., photoreceptors included on vision chips). A polynomial-time programming algorithm for embedding the desired circuit graph onto the prefabricated routing resources is presented, and is implemented as part of a general design tool for specifying, manipulating and comparing circuit netlists. This thesis presents a system intended to facilitate analog circuit design. At its core is a VLSI chip that is electrically configured in the field by selectively connecting predesigned elements to form a desired circuit, which is then tested electrically. The system may be considered a hardware accelerator for simulation, and its large capacity permits testing system ideas, which is impractical using current means. A fast-turnaround simulator permitting rapid conception and evaluation of circuit ideas is an invaluable aid to developing an understanding of system design in a VLSI context. We have constructed systems using both reconfigurable interconnection switches and laser-programmed interconnect. Prototypes capable of synthesizing circuits consisting of over 1000 transistors have been constructed. The flexibility of the system has been demonstrated, and data from parametric tests have proven the validity of the approach. Finally, this thesis presents several new circuits that have become key components in many analog VLSI systems. Fast, dense and provably safe one-phase latches and hierarchical arbiters are presented, as are a low-noise analog switch, an isotropic novelty filter, a dense, active high-resistance element, and a subthreshold differential amplifier with a large linear input range.

The Phase Rotor Filter

Abstract: We report creation by photolithography techniques of the phase rotor filter, an optical element whose complex transmittance depends in a linear fashion on the azimuth angle. Relationships are given that describe the scalar diffraction of coherent light by the rotor filter. The results of the numerical simulation and experiments are discussed.

An extended Kalman filter approach to rotor time constant measurement in PWM induction motor drives

Abstract: A rotor time constant estimation technique for the purpose of updating the control gains of an induction motor field-oriented controller is described. An extended Kalman filter is employed to estimate the inverse rotor time constant online only using measurements of the stator voltages and currents and rotor speed of an induction motor. The motor is driven by a pulsewidth modulated (PWM) inverter with or without current feedback loops. By utilizing the wideband harmonic contents inherent in conventional PWM voltage waveforms, no external random test signal is required for parameter estimation. Both computer simulation and experimental results show that the filter is capable of estimating the rotor time constant while the rotor speed is either constant or time varying. >

System and method for improved speech acquisition for hands-free voice telecommunication in a noisy environment

Abstract: Systems and methods for improved speech acquisition are disclosed including a plurality of linearly arrayed sensors to detect spoken input and to output signals in response thereto, a beamformer connected to the sensors to cancel a preselected noise portion of the signals to thereby produce a processed signal, and a speech recognition system to recognize the processed signal and to respond thereto. The beamformer may also include an adaptive filter with enable/disable circuitry for selectively training the adaptive filter a predetermined period of time. A highpass filter may also be used to filter a preselected noise portion of the sensed signals before the signals are forwarded to the beamformer. The speech recognition system may include a speaker independent base which is able to be adapted by a predetermined amount of training by a speaker, and which system includes a voice dialer or a speech coder for telecommunication.

A Simple Multivariate Filter for the Measurement of Potential Output

Abstract: This paper examines techniques that have been used to estimate potential output and finds them wanting. We suggest a simple multivariate-filtering technique that is a generalization of the Hodrick-Prescott univariate filter. In univariate filters, only information about a variable itself is used in eliminating noise in order to obtain an estimate of the underlying trend. […]

Blindzone signal indicator

Abstract: A display apparatus for blindzone signal indication comprises an exterior rear view mirror housing and an exterior rear view mirror disposed in the exterior rear view mirror housing. The exterior rear view mirror defines a portion from which light is reflected and a portion through which light may be transmitted from inside the rear view mirror housing. A light source mounted within the housing is located at the light transmissive portion of the mirror and a directional filter located at the light transmitting portion of the mirror filters light emitted by the light source so that a signal from the light source may be seen from the interior of the vehicle, but may not be seen by drivers of other vehicles.

Digital shaping filters for reducing machine vibration

Abstract: A digital shaping filter used to shape the input to digitally controlled flexible plants is derived from an input preshaping technique to reduce residual vibration in the plant output. Results from simulations show that these filters reduce plant residual vibration to zero. In addition, an arbitrary rate digital shaping filter is derived that allows the user to select any sampling rate for the digital system. The examination of these filters in the digital Z domain reveals them to be digital notch filters that are robust to vibration-mode parameter shifts. >

Time-domain filter bank analysis: a new design theory

Abstract: The authors present a new time-domain approach for the analysis and design of a broad class of general analysis/synthesis systems based on M-band filter banks. They derive a set of time-domain conditions for reconstruction which can be used directly in a filter bank design procedure. The general and unrestricted nature of this framework allows for the design of many useful banks. In addition to the complete derivation of the time-domain conditions, they also describe the associated filter bank design procedure and a number of design examples are included. >

A 10.7-MHz 68-dB SNR CMOS continuous-time filter with on-chip automatic tuning

Abstract: A maximally flat 10.7-MHz fourth-order bandpass filter with an on-chip automatic tuning system is presented. The signal-to-in-band integrated noise ratio (SNR) of the automatically tuned filter is around 68 dB. The third intermodulation distortion (IM3) is lower than -40 dB for a two-tone input signal of 3.2 V peak to peak (V/sub p-p/). The complete system operates with supply voltages of +or-2.5 V. The power consumption of the system is 220 mW. All this has been achieved due to the use of a low-distortion transconductor, the development of a high-frequency CMOS resistor, and the realization of an advanced on-chip automatic tuning system for both frequency and bandwidth control. The chip has been fabricated in a standard 1.5- mu m n-well CMOS process. >

Simplified set-top converter for broadband switched network

Abstract: For fiber-to-the-curb program switching, which is done at the central office, the same fixed frequency slot is always used for distributing the TV program selected for a video recording device at the subscriber's premises; for its related display, another selected slot is always used for distributing another selected TV program; the set-top converter is provided with two narrow band filters, one for each dedicated slot, instead of expensive tuners; the same set-top converter can be used in other rooms of the subscriber premises, except using a plug-in tuner for placing additional selected TV programs received from remaining, nondedicated slots into the same filter band used for the TV associated with the video recording device.

Design and first applications of a post-column imaging filter

Abstract: We have designed and built an imaging filter which can be attached to most standard TEMs, and is capable of operating at primary energies of up to 400 keV. The filter uses a 90° magnetic sector prism, a piezoelectrically controlled energy-selecting slit, and 6 quadrupole and 5 sextupole lenses. It fully corrects second-order aberrations and distortions in images formed with electrons of selected energies, and it also produces second-order aberration-corrected spectra of variable dispersion. We show the first applications of the filter at 200 keV primary energy, which indicate that the filter will excel in chemical mapping and spectroscopy, in improving contrast of electron images and diffraction patterns, and in making high resolution electron microscopy and diffraction more quantitative. We conclude the paper with a discussion about atomic resolution image formation using inelastically scattered electrons, and the relationship between energy-filtered diffraction patterns and images formed with electrons of the same energy.

Analog CMOS Filters for Very High Frequencies

Abstract: Preface. 1. Introduction. 2. Filter Synthesis for (very) High Frequencies. 3. Effect of Non-Idealities. 4. Transductor Design. 5. Tuning. 6. Filter Realizations. 7. Conclusions. References. Subject Index.

An adaptive morphological filter for image processing

Abstract: Novel types of opening operator (NOP) and closing operator (NCP) are proposed. An adaptive morphological filter is then constructed on the basis of the NOP and NCP. The filter can remove any details consisting of fewer pixels than a given number N, while preserving the other details. Efficient algorithms are also developed for the implementation of the NOP and NCP. >

Dynamic filter system

Abstract: A dynamic filter system comprises a dynamic filter assembly including one or more filter elements (148) and one or more members (151) disposed within a housing (105). The filter elements and the members are interleaved and arranged to rotate with respect to one another to resist fouling of the filter elements.

Method and apparatus for testing the integrity of filter elements

Abstract: A method and apparatus for testing the integrity of filter elements is provided. The filter assembly comprises a plurality of filter elements which are subdivided into a plurality of sections. By measuring the gas flow rate under known pressure conditions through all of the sections or a selected portion of the sections, defective filter elements can be isolated in a systematic manner.

A filter based bit allocation scheme for subband compression of HDTV

Abstract: The authors compare the subband compression capabilities of eight filter sets (consisting of linear-phase quadrature mirror filters (QMFs), perfect reconstruction filters, and nonlinear phase wavelets) at different bit rates, using-a filter-based bit allocation procedure. Using DPCM and PCM in HDTV subband coding, it is found that QMFs have an edge over the rest. >

Physical origins of input filter oscillations in current programmed converters

Abstract: Addition of an input filter to a current-programmed converter can cause the controller to oscillate. Two instability mechanisms can typically occur: (1) the current programmed controller effective current feedback loop may become unstable, or (2) the controller effective input voltage feedforward loop, which becomes a positive feedback loop when an input filter is added, may oscillate. Three design criteria for preventing oscillations are derived and interpreted. When all three criteria are well satisfied, then the output voltage regulation loop gain is unchanged. Hence, input filters of current programmed converters can be designed in essentially the same manner as for duty-ratio programmed converters. Results are summarized in tabular form for the basic buck, boost, and buck-boost converters. Experimental measurements for a buck converter with different input filters support the theoretical predictions. >

Blood separation filter assembly and method

Abstract: Blood separation filter assemblies and methods are provided to quickly and completely separate plasma or serum from whole blood without the need of centrifugation. The filter assemblies and methods have filter materials of a predetermined thickness which are maintained under positive pressure during use. The filter materials have at least one layer of glass fibers having an average fiber diameter ranging from 0.2 μm to 7.0 μm and which are compressed at least 25% in thickness.

Tunable BiCMOS continuous-time filter for high-frequency applications

Abstract: A BiCMOS fully differential transconductor based on MOS transistors operating in the linear region is presented. The circuit has an equivalent nondominant pole located above 1.5 GHz. This makes it suitable for high-frequency continuous-time filters. A second-order low-pass filter using the new transconductor realized in a 2- mu m BiCMOS technology is reported. The cutoff frequency f/sub 0/ of the cell is tunable in the range of 8-32 MHz and the quality factor is 2. The filter THD stays lower than -40 dB for an output signal up to 3.2 V/sub p-p/ at 5-MHz frequency. The area of the cell is 0.322 mm/sup 2/ and the power consumption (with f/sub 0/=25 MHz) is 30 mW with a single 5-V power supply. >

A Resolver-to-Digital Conversion Method for Fast Tracking

Abstract: In this paper, we propose a new R/D (Resolver-to -Digital) conversion method, in which a bang-bang type phase comparator is employed for fast tracking. We eliminate from the R/D conversion loop the low-pass filter which is needed to reject carrier signal and noise. Instead, we employ two prefilters outside the R/D conversion loop that take the role of the low-pass filter. Thereby, we can construct a fast and accurate tracking R/D converter. Some simulation and experimental results as well as mathematical performance analysis are presented to demonstrate the superior tracking performance of our R/D converter over conventional tracking R/D converters.

Fuzzy data processing method and data smoothing filter

Abstract: A unique data processing method and a fuzzy smoothing filter are disclosed which employ a three-dimensional elliptic membership function based on the fuzzy logic to remove noises from data including a sequence of measured points for evaluating the linearity of the measured points. The evaluation is carried out by superimposing the center of an ellipse represented by an elliptic membership function on a substantial central portion of inputted data, evaluating a factor representing the linearity of the inputted data by summing the degrees of membership derived at respective inputted data, calculating the ratio of the factor to a factor representing an ideal linearity of the inputted data, rotating the ellipse by a predetermined angular distance to derive the ratio at that position, repeating the rotating step until the peak is found, and determining the ratio when the peak is found as the linearity of the inputted data. The fuzzy smoothing filter is comprised of a data input for inputting data to be smoothed, a multi-dimensional membership function generator for calculating a degree of membership for the inputted data, a calculator for deriving an angle of the data and calculating the linearity of the data, smoothing processors coupled to receive the angle and the linearity of the data from the calculator for executing a smoothing operation in a plurality of modes, a selector for selecting one mode from among the plurality of smoothing modes, and a store for holding smoothing filter parameters supplied to the calculator and the selector.

Asynchronous peak detection of information embedded within PRML class IV sampling data detection channel

Abstract: A digital peak detection circuit asynchronously detects embedded overhead information such as servo or sync pattern data within a PR4,ML synchronous data detection channel of a magnetic disk drive. The channel includes an analog to digital converter clocked by a data clock operating asynchronously with respect to playback of the embedded overhead information in the channel for converting an analog data stream into raw data samples, and an adaptive digital FIR filter for conditioning the raw data samples into conditioned data samples in accordance with programmable filter coefficients. The digital peak detection circuit includes a filter adaptation circuit for programming the digital FIR filter to a bandwidth characteristic selected for the embedded overhead information, a plurality of tapped clock delays each connected in tandem to receive and progressively by a period related to said data clock to delay conditioned data samples of the embedded overhead information, a first comparison logic array connected to predetermined taps of said tapped data clock period delays for comparing said conditioned data samples of the embedded overhead information at said taps and for generating a first logical condition therefrom, a second comparison logic array connected to a predetermined tap of said tapped clock delay means and to a threshold-providing circuit, for comparing the conditioned data samples of the embedded overhead information at the taps with threshold values provided by the threshold-providing circuit and for generating a second logical condition therefrom, and a digital combining circuit for combining the first logical condition and the second logical condition in order to detect and put out the embedded overhead information. A fault tolerant sync pattern detection method and apparatus is also disclosed.

Phase retrieval from a set of intensity measurements: theory and experiment

Abstract: The method for phase retrieval from a set of intensity measurements is described and thoroughly investigated. This method is based on application and further minimization by gradient procedures of the functional of reconstruction error in all the planes of recording. The method is shown to result in the well-known Gerchberg–Saxton algorithm [ Optik (Stuttgart)35, 237 ( 1972)] if two intensity measurements (in the pupil and the focal planes of a lens) are used. Numerical simulation revealed the following advantages of the method: the convergence of iterative procedures is improved, the range of reconstruction turns out to be wider, and the stability of procedures with respect to the additive noise in intensity measurements is enhanced. Experimental data confirming the conclusions of numerical simulation are presented. A nonlinear optical spatial filter is also described. The possibility of applying this filter to the problem of recovering phase from intensity measurements in the input and the output planes of the filter is shown.