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7580964 Hardware-efficient phase-to-amplitude mapping design for direct digital frequency synthesizers  
A hardware-efficient mapping circuit uses a base decoder to decode the control signal (the most significant bits “MSBs” of the phase angle) to provide a base value. A controller maps the...
7512646 Precision complex sinusoid generation using limited processing  
A first phasor associated with an electronic signal and a delta phasor associated with a cyclic rate of the electronic signal are multiplied to produce a second phasor. To compensate for any...
7509363 Method and system for approximating sine and cosine functions  
A technique for approximating output values of a function based on LaGrange polynomials is provided. Factorization of a LaGrange polynomial results in a simplified representation of the LaGrange...
7498852 Phase error correction circuit for a high speed frequency synthesizer  
Circuits, methods, and apparatus for adjusting an NCO output in order to provide a signal that is phase-locked to a reference signal. This is particularly beneficial where the frequencies of the...
7440987 16 bit quadrature direct digital frequency synthesizer using interpolative angle rotation  
A direct digital synthesizer employs a trigonometric function generator utilizing decomposition of a larger angle into smaller sub-angles, interpolation of a desired sub-angle between two known...
7437391 Numerically controlled oscillator and method of operation  
In one embodiment, the present invention is directed to a numerically controlled oscillator. The numerically controlled oscillator comprises: a phase accumulator for receiving an input digital...
7321911 Method of generating sinusoidal signal  
Methods, devices and a software product for generating a sinusoidal signal of a desired frequency at a desired sampling rate. If the frequency is higher than the upper limit, a coefficient is...
7260592 Addressing mode and/or instruction for providing sine and cosine value pairs  
The present invention relates to a method and system for providing sine and cosine value pairs in a processor. The method includes decoding a sine and cosine instruction having a predetermined...
7103622 Direct digital synthesizer with output signal jitter reduction  
A method and apparatus for reducing unwanted harmonics in direct digital synthesizer (DDS) output. The method comprises the steps of providing a set of k phase-shifted clock signals, examining, in...
7072925 Generator structures and methods that provide low-harmonic curvilinear waveforms  
Simple, inexpensive waveform generators and methods are provided that generate curvilinear waveforms which comprise a fundamental sinusoid and harmonics that are either absent or are significantly...
7064616 Multi-stage numeric counter oscillator  
A numeric counter oscillator is disclosed comprising a quotient accumulator and a remainder accumulator. The quotient accumulator has a programmable input for receiving a QUOTIENT value, a...
7031992 Hardware function generator support in a DSP  
The present invention relates to digital signal processors with an integrated module configured to compute a Coordinate Rotation Digital Computer (CORDIC) in a pipeline. The pipelined module can...
7026846 Synthesizer structures and methods that reduce spurious signals  
Synthesizers are provided to generate synthesizer signals in response to primary digital signal representations that are created by a signal generator. In an important feature, the synthesizers...
6976043 Technique for approximating functions based on lagrange polynomials  
A technique for approximating output values of a function based on LaGrange polynomials is provided. Factorization of a LaGrange polynomial results in a simplified representation of the LaGrange...
6892213 Digital sine/cosine wave generator  
A digital sine/cosine wave generator generates discrete values representative of either a sine wave or a cosine wave. The digital sine/cosine wave generator generates sine and/or cosine waves by...
6640237 Method and system for generating a trigonometric function  
A method for generating a trigonometric function is provided that includes an input angle being received and automatically separated into a first component angle and a second component angle. A...
6611156 Waveform data generation apparatus  
A first waveform data storage portion stores sine wave data or cosine wave data in either of the angular sections on both sides of a zero-crossing point of a sine wave or a cosine wave, each of the...
6587863 Multiphase, interleaved direct digital synthesis methods and structures  
Direct digital synthesis (DDS) methods and structures are provided that increase DDS output frequencies f out without requiring a corresponding increase in the rate f clk at which DDS structures...
6587862 Apparatus and method for direct digital frequency synthesis  
An apparatus and method are provided for synthesizing a variable frequency sinusoidal waveform. The apparatus and method exploit octant symmetry properties of sine and cosine waveforms, when taken...
6581079 Apparatus for computing transcendental functions quickly  
The invention provides a method and system for computing transcendental functions quickly: (1) the multiply ALU is enhanced to add a term to the product, (2) rounding operations for intermediate...
6549924 Function generating interpolation method and apparatus  
An input number is applied to a look-up table that supplies three coefficients based upon certain bits of the input that define a series of bins. The first coefficient is fed directly to an adder...
6519619 Circuit for generating periodic function  
A circuit for digitally generating a series of encoded sampling values of a periodic function by virtue of ROM table conversion, include (a) a function ROM in which an amplitude associated with...
6480871 Algorithm (Method) and VLSI architecture for fast evaluation of trigonometric functions  
A fast CORDIC algorithm and the resulting VLSI architecture for the evaluation of trigonometric functions are disclosed. The new method employs signed digits to represent intermediate operands and...
6470367 Apparatus and method for implementing an inverse arctangent function using piecewise linear theorem to simplify  
The present invention discloses an apparatus and method for implementing an inverse arctangent function using piecewise linear theorem to simplify and used to transform a right-angled coordinate...
6470366 Angle calculation circuit  
A sign determination circuit is input with in-phase signal I, and outputs in-phase sign determination signal S PI to indicate the sign, positive or negative, of in-phase signal I. Another sign...
6434582 Cosine algorithm for relatively small angles  
A system and method for computing the cosine of an input value. The system comprises a logical processing unit and an addition unit. The logical processing unit comprises an input bus with a...
6396314 Arrangement for the warbling (sweeping) of a frequency synthesizer  
For sweeping a frequency synthesizer, which is digitally tunable in frequency in small steps to have a predetermined frequency progression over time, a clock signal of an accumulator generating...
6385632 Fast CORDIC algorithm with sine governed termination  
A system and method for evaluating one or more functions using a succession of CORDIC stages/iterations followed by a residual rotation. The succession of CORDIC stages are preferably partitioned...
6373316 Digital cosine and sine multiplication circuits  
By sampling at six times the carrier frequency cosine and sine multiplication circuits are found to be constructable from simple shift and inversion circuit. Shifting and inversion are controlled...
6366939 Apparatus for computing exponential and trigonometric functions  
A 64-bit precision digital circuit for computing the exponential function and a related 64-bit precision digital circuit for computing sine and cosine, each circuit comprising a master circuit and...
6330578 Method and apparatus for digitally representing a waveform  
A method and apparatus for digitally representing a waveform segment defined by discrete ordered pairs of abscissae and ordinates, the ordered pairs being divided into an odd set and an even set....
6320431 Apparatus and method of generating numerically controlled oscillator signals  
An apparatus according to a preferred embodiment of the present invention includes two memories each storing different octants of a sine (or cosine) waveform. The sine and cosine waveforms may be...
6255866 Digital phase analyzer and synthesizer  
A digital phase synthesizer includes a source of successive phase data signals. An interpolator generates successive edge placement data signals in response to each of the successive phase data...
6188261 Programmable delay generator and application circuits having said delay generator  
A programmable delay generator comprises a first ramp wave generator and a second ramp wave generator, each having the same structure as each other, each of them operating with external common...
6141670 Apparatus and method useful for evaluating periodic functions  
A computer and a method of using the computer to reduce an original argument to obtain a periodic function of the argument. A special number P j is employed that is close to a nontrivial...
6104411 Electronic computing apparatus having graph displaying function and method for displaying graph  
There are provided an electronic computing apparatus having a graph displaying function and a graph displaying method which allow an optimum graph to be quickly displayed. A graph is displayed on a...
6066967 Phase-coherent frequency synthesis with a DDS circuit  
An improved circuit and technique for obtaining phase-coherent synthesis using a direct digital synthesizer (DDS). In the phase-coherent frequency synthesis device of the invention, a computational...
6064241 Direct digital frequency synthesizer using pulse gap shifting technique  
A direct digital frequency synthesizer includes inputs for a reference clock signal and a control word, and an output for a synthesized clock signal. A phase accumulator coupled to the input for...
6014682 Methods and apparatus for variable-rate down-sampling filters for discrete-time sampled systems using a fixed sampling rate  
Methods and apparatus for variable-rate down-sampling filters for discrete-time sampled systems using a fixed sampling rate are disclosed. The Variable Rate Down-Sampling Filter allows a continuous...
6011448 Method and apparatus for frequency modulation synthesis  
A method for frequency modulation synthesis and apparatus for performing the method. The method uses additions rather than multiplies and therefore saves the space and cost of multipliers in...
5999581 Low-power direct digital frequency synthesizer architecture  
A direct digital frequency synthesizer for generating a digital sine or cosine function waveform receive digital input. Memory stores digital samples along portions of sine and cosine function...
5986483 Direct digital frequency systhesizer  
A direct digital frequency synthesizer outputting a sine signal is disclosed, comprising an accumulator, a symmetry circuit, a coarse circuit, a fine circuit and a sign circuit, wherein the...
RE36388 Sine/cosine generator and method  
A sine/cosine generator with coarse and fine angles having compressed sine and cosine read only memories (ROMS) by use of symmetry of coarse angles about π/4 and, optionally, symmetry of fine...
5954787 Method of generating sine/cosine function and apparatus using the same for use in digital signal processor  
A method of generating sine/cosine function and an apparatus using the same in digital signal processor are disclosed. The method for generating sine/cosine function values corresponding to a first...
5937438 Sine/cosine lookup table  
A lookup table includes a complementer, a memory and a switching element. The complementer selectively complements a subset of bits of a multibit designation of an angle based on a most significant...
5898325 Dual tunable direct digital synthesizer with a frequency programmable clock and method of tuning  
A dual-tunable direct digital synthesizer is provided with a programmable frequency multiplier that multiplies a relatively low frequency fixed clock signal F clk so that the output frequency F o ...
5892692 Method for generating a lookup table for a digital oscillator  
A digital waveform oscillator generates digitized waveforms without distortion using a lookup table. The frequencies which may be generated using direct lookup tables at their fundamental table...
5889853 Adjustable-period dual-tone multifrequency generator  
An adjustable-period dual-tone multifrequency (DTMF) generator, which includes a plurality of programmable counters or up/down counters, a control unit, a memory unit for storing data, a digital...
5859787 Arbitrary-ratio sampling rate converter using approximation by segmented polynomial functions  
A method for resampling includes convolving a given set of samples with the impulse response function of a low-pass filter. In this method, values of the impulse response required for the...
5822376 High-speed multiplier to multiply a digital signal by a periodic signal  
Disclosed is a digital multiplication circuit to multiply a digital signal SN by a periodic waveform that is, in principle, a sine waveform. This circuit uses a phase digital generator φ varying...
Matches 1 - 50 out of 222 1 2 3 4 5 >