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5341387 Viterbi detector having adjustable detection thresholds for PRML class IV sampling data detection  
A Viterbi detector for a PR4,ML data channel includes a data sample input for receiving digital data samples from a source. Digital data samples are taken of data which has been coded in a...
5339263 Combined decimation/interpolation filter for ADC and DAC  
A COMBINED DECIMATION/INTERPOLATION FILTER FOR ADC AND DAC (analog-to-digital converter and digital-to-analog converter) provides a single filter which may be used both as a decimation filter and...
5337264 Time reversal gaussian approximation filter  
A time reversal filter uses exponential decay infinite impulse response filters to achieve an approximation to a true Gaussian low pass filter. In one embodiment, a time reversal Gaussian...
5331583 Running-average/decimation filter for an oversampling A/D converter  
A filter processing unit 2 receives the output of an oversampling-type analog/digital (A/D) converter circuit 1. Predetermined information is acquired by a compensation circuit 3-1 with...
5325317 Digitally programmable linear phase filter having phase equalization  
A digitally programmable Bessel filter includes a plurality of serially connected stages or biquads with each biquad including a plurality of programmable operational transconductance amplifiers....
5315539 Method and apparatus for debouncing signals  
Debounce and lockout filters include an input part for receiving a plurality of input signals from switches, a microprocessor and an output part. The filters simultaneously process a plurality of...
5289395 Signal processing method employing a digital filter  
A method is disclosed for processing a signal having a monochromatic signal component with the aid of a digital filter. The method includes determining the real amplitude, phase and frequency of...
5283813 Methods and apparatus particularly useful for blind deconvolution  
A method and apparatus for controlling an equalizer receiving the output of an unknown system in order to produce a desired response for recovering the input to the system are characterized by...
5278910 Apparatus and method for speech signal level change suppression processing  
A level measuring circuit first measures a level of an input speech signal. Next, a coefficient calculating circuit determines a value for suppressing a change of the level of the input speech...
5258933 Timing control for PRML class IV sampling data detection channel  
A multi-mode timing loop for a PR4,ML sampled data channel includes an analog to digital converter and a digital finite impulse response filter for providing conditioned digital samples. The...
5255202 Digital signal processing method and system, electric power system signal processing system and electric power control system  
Analog signals are sampled and converted into digital data which is then filtered by a digital filter. The filtered digital data is then subjected to an arithmetic operation. The blocking band of...
5255215 Digital filter system with changeable cutoff frequency  
Using stored discrete samples of filter coefficients at each of a plurality of discrete operating points, a filter control (e.g., CPU) provides dynamic control of a digital filter through an...
5250748 Tone signal generation device employing a digital filter  
An address signal generation circuit generates an address signal which changes at a rate corresponding to tone pitch of a tone to be generated. This address signal consists of an integer section...
5249150 Process and circuit to determine estimates of the instantaneous value of parameters of at least one sinusoidal signal with constant and known frequency which is an additive component of a measuring signal  
A circuit and method for iteratively estimating Fourier coefficients of one or more Fourier components of a measuring signal utilizes a filter to determine the Fourier coefficients for sampling...
5235534 Method and apparatus for interpolating between data samples  
A method and apparatus for interpolating between data samples (VS) that preserves the frequency spectrum of a sampled analog signal (VO) is provided. Data samples (VS) are interpolated to produce...
5227972 Matched filter data smoothing system  
An efficient spatial smoothing algorithm for filtering data while preserving spatial detail is obtained using the system (impulse response) function of the sensor. In contrast to the normal...
5226057 Receiver and adaptive digital notch filter  
Adaptive IIR digital notch filters useful with RF receivers for reducing interference. One or more notch filters automatically tune, to an interferer frequency, via adapting of coefficients in the...
5224061 Method of and arrangement for restoring invalid samples of an equidistantly sampled signal  
A method and apparatus for replacing invalid samples of an equidistantly sampled signal with corrected samples derived from an environment of valid samples preceding and following the invalid...
5193070 Transversal filter circuit having tap circuits including bidirectional shift registers for serial multiplication  
A transversal filter circuit including a plurality of tap circuits, each having a serial multiplication circuit having a simplified construction and not requiring a shift of decimal (binary)...
5150317 Adaptive digital filter which is responsive to the rate of change of an input signal  
The time constant of an adaptive digital filter is regulated as a function of the magnitude of the rate of change of the input signal to the filter. When the input signal has a large step input or...
5149902 Electronic musical instrument using filters for timbre control  
A filter calculating section has a plurality of basic filters formed on a time-divisional basis. The timbre of a musical tone signal is controlled by a memory section, an accumulator, a selector,...
5144569 Method for filtering digitized signals employing all-pass filters  
A method for filtering digital input signals (e) makes use of all-pass filters of a first-class having the transfer function S1 and all-pass filters of a second-class having the transfer function...
5142170 High repetition rate signal reject apparatus and method  
A circuit is illustrated for eliminating a repetitiously occurring or constant frequency pulse signal from a train of signal pulses. The design is such that a plurality of such circuits can be...
5140543 Apparatus for digitally processing audio signal  
A digital signal processing apparatus for digitally performing a limiting or compressing process with respect to an input signal. The apparatus includes a comparator responsive to the input signal...
5130938 Device and method for filtering weight indicative signal from weighing device  
A digital filter for filtering a weight indicative signal provided by a weighing device to remove undesirable oscillatory components caused by mechanical vibration of the weighing device. The...
5122718 Gain/phase compensation circuit for use in servo control system of optical disk device  
A gain and phase compensation circuit for use in the servo control system for an optical disk device comprises a digital signal input terminal for receiving an input digital signal to be treated,...
5119321 Adaptive threshold suppression of impulse noise  
Impulse noise suppression upstream of digital processing circuitry contains a sample and hold mechanism which samples the input signal and stores a plurality of sequential sample values...
5105377 Digital virtual earth active cancellation system  
A digital virtual earth active cancellation system which receives a phenomena input signal representing residual phenomena to be cancelled and has an adaptive filter which generates a cancellation...
H001005 Gram-Schmidt space-time adaptive filter using transverse orthonormal ladder filters  
A space-time adaptive filter system is provided for eliminating unwanted signals from a radar or communication system. The filter system receives a main channel and several auxiliary channels...
5068799 System and method for detecting flaws in continuous web materials  
A method and apparatus for detecting flaws in continuous web material illuminated by a light source and optically scanned to produce a digitalized electronic image of said material. The digitized...
5056054 Digital phase locked loop utilizing a multi-bit phase error input for control of a stepped clock generator  
A digital loop filter translates a multi-bit phase error input into a high resolution control signal utilizable as an advance-retard control for a multi-phase clock generator. The digital filter...
5051942 Method and apparatus for calculating filter factors  
A transfer function is determined in accordance with an amplitude characteristic and a phase characteristic. The transfer function is subjected to inverse Fourier transform. An imaginary part of a...
5043653 Noise filter for zero crossing detector  
A noise filter for the zero crossing detector of a digitized sine wave signal uses an adjustable noise integrator. The noise integrator incorporates a counter. The integration characteristic of...
5027410 Adaptive, programmable signal processing and filtering for hearing aids  
A hearing aid system utilizes digital signal processing to correct for the hearing deficit of a particular user and to maximize the intelligibility of the desired audio signal relative to noise....
5027423 Image-processing integrated circuit device  
An image-processing integrated circuit device comprises a delay circuit and adder group, a multiplication block group, and an adder group. Image data in a window are fed to the delay circuit and...
5025453 Method of measuring the signature of digital transmission equipment, and apparatus for implementing such a method  
A method of measuring the signature of digital transmission equipment, in which the measurement can be performed during operation without adding special apparatus, and in which: the digital...
5016207 High-speed digital filter processor including parallel paths for processing data, suitable for use in spatial filter image processing  
A digital filter processor includes an input part for distributing an input digital data train including a plurality of digital data to a plurality of systems. Each of the systems is provided with...
5010507 Sampled digital filter system  
A sampled digital filter system for filtering a signal that has a frequency lower than an unwanted signal component in the input signal. The digital filter system samples the input signal in...
4970637 Digital anti-aliasing filter  
An original analog signal is supplied to A/D converter 2 through analog LPF 1. LPF 1 has a cutoff frequency of fa/2 (fa is the frequency of a clock pulse supplied to A/D converter 2). LPF 1 limits...
4958311 Composite finite impulse response digital filter  
A composite finite impulse response digital filter for use in an image processing apparatus or the like includes a plurality of sub-filters connected in series. In each sub-filter, a random access...
4953118 Nonrecursive half-band filter  
A nonrecursive half-band filter which permits the conversion of a complex-value input signal into a complex-value output signal. The pulse response of the filter is modulated onto a complex...
4953116 Digital word output high-pass filter apparatus  
A high-pass filter which provides a digital word output indicative of a high-pass filter function of the quantity of logic "1" inputs to the counter. The output of a counter is low-pass filtered...
4947480 Multichannel signal enhancement  
A mixed adaptive filter is formulated for the signal processing problem where desired a priori signal information is not available. The formulation generates a least squares problem which enables...
4941185 Image processing  
A method and apparatus for processing a first (e.g. half-tone) image constituted by a second (e.g. continuous tone) image convolved with a periodic (screen) function, to produce the second image...
4939576 Adaptive ringing reducer for television signal processing  
A method for reducing ringing artifacts caused by low pass filtering of baseband television signals comprises the steps of: detecting the occurrence of a horizontal transition in the baseband...
4933978 Method and apparatus for determining the value of a sample in the mth position of an ordered list of a plurality of samples  
A method and apparatus for determining the value of a sample having a particular position in an ordered ranking, by magnitude, of a set of digital samples includes means for truncating the lesser...
4931972 Multiple-input digital filter  
A multiple-input digital filter capable of filtering a plurality of digital input signals with a single filtering device first latches the input signals and then sequentially selects each of the...
4908787 Interpolator/decimator filter structure and a notch filter therefor  
A filter structure including a notch filter is designed to have a transmission zero at a frequency slightly displaced from one half of the lower sampling rate of the interpolator/decimator, and...
4896285 Calculation of filter factors for digital filter  
An apparatus for calculating a filter factor for a digital filter which can be simply constructed and in which the time period for calculation can be shortened as compared with conventional...
4893316 Digital radio frequency receiver  
A digital radio receiver is described. The digital receiver of the present invention contemplates a digital radio receiver which operates on a received analog signal which has been converted to a...