Showing papers on "Sine wave published in 2004"

Method and apparatus for controlling power factor correction

Abstract: In a method and apparatus for controlling power factor correction in mixed operation modes, a frequency of the input voltage is obtained by detecting the zero crossing points of the input voltage. A peak of the input voltage is obtained by detecting input voltage with 90 degree phase. Thus, the present invention predicts the input voltage by its frequency and peak and the characteristic of the sine wave. A digital signal processor computes the duty and frequency of a boost switch, switching the operation mode of the boost converter among continuous mode, critical mode and discontinuous mode according to input voltage or the load. According to another aspect, the operation is switched to critical mode from the average current mode when a zero current is detected before the charging and recharging cycle of the boost switch is finished.

An 800-MHz low-power direct digital frequency synthesizer with an on-chip D/a converter

Abstract: An 800-MHz low-power direct digital frequency synthesizer (DDFS) with an on-chip digital-to-analog (D/A) converter is presented. The DDFS consists of a phase accumulator, two phase-to-sine converters, and a D/A converter. The high-speed operation of the DDFS is enabled by applying parallelism to the phase-to-sine converter and by including a D/A converter in a single chip. The on-chip D/A converter saves delay and power consumption due to interchip interconnections. The DDFS considerably reduces power consumption by using several low-power techniques. The pipelined parallel accumulator consumes only 22% power of a conventional pipelined accumulator with the same throughput. The quad line approximation (QLA) and the quantization and error ROM (QE-ROM) minimize the ROM to generate a sine wave. The QLA saves 4 bits of the sine amplitude by approximating the sine function with four lines. The QE-ROM quantizes the ROM data by magnitude and address and then it stores the quantized values and the quantization errors separately. The ROM size for a 9-bit sine output is only 368 bits. A DDFS chip is fabricated in a 0.35-/spl mu/m CMOS process. It consumes only 174 mW at 800 MHz with 3.3 V. The chip core area is 1.47 mm/sup 2/. The spurious-free dynamic range (SFDR) is 55 dBc.

Elastic contact stiffness and contact resistance for the Weierstrass profile

Abstract: The Weierstrass series comprises a system of superposed self-affine sine waves that can be used to define a simple idealization of a two-dimensional fractal rough surface profile. The load–compliance relation for the contact of this profile with a rigid plane is here estimated using Westergaard's solution for the contact of a single sine wave with a plane and various approximations concerning the interaction of the different terms in the series. These approximations are compared with a numerical solution for the contact of the profile defined by the first few terms of the series. Once the load–compliance relation is established, the electrical contact resistance can be determined, using an analogy between the conduction and incremental elastic contact problems. The results show that these simple estimates give quite good predictions of the relations between load, compliance and contact resistance. They also confirm that these relations are largely determined by the coarse scale features of the surface profile, in contrast to the predictions of classical asperity model theories.

Improved determination of the best fitting sine wave in ADC testing

Abstract: The sine wave test of an analog-to-digital converter (ADC) means to excite the ADC with a pure sine wave, look for the sine wave which best fits the output in least squares (LS) sense, and analyze the difference. This is described in the IEEE standards 1241-2000 and 1057-1994. Least squares is the "best" fitting method most of us can imagine, and it yields very good results indeed. Its known properties are achieved when the error (the deviation of the samples from the true sine wave) is random, white (the error samples are all independent), with zero mean Gaussian distribution. Then, the LS fit coincides with the maximum likelihood estimate of the parameters. However, in sine wave testing of ADCs, these assumptions are far from being true. The quantization error is partly deterministic, and the sample values are strongly interdependent. For sine waves covering less than, say, 20 quantum levels, this makes the sine wave fit worse than expected, and since small changes in the sine wave affect the residuals significantly, especially close to the peaks, ADC error analysis may become misleading. Processing of the residuals [e.g., the calculation of the effective number of bits, (ENOB)] can exhibit serious errors. This paper describes this phenomenon, analyzes its consequences, and suggests modified processing of samples and residuals to reduce the errors to negligible level.

96-GHz static frequency divider in SiGe bipolar technology

Abstract: A static frequency divider designed in a 210-GHz f/sub T/, 0.13-/spl mu/m SiGe bipolar technology is reported. At a -5.5-V power supply, the circuit consumes 44 mA per latch (140 mA total for the chip, with input-output stages). With single-ended sine wave clock input, the divider is operational from 7.5 to 91.6 GHz. Differential clocking under the same conditions extends the frequency range to 96.6 GHz. At -5.0 V and 100 mA total current (28 mA per latch), the divider operates from 2 to 85.2 GHz (single-ended sine wave input).

Anti-control of chaos of two-degrees-of-freedom loudspeaker system and chaos synchronization of different order systems

Abstract: The chaos anti-control and synchronization of a two-degrees-of-freedom loudspeaker system are studied in this paper. Anti-control term is added to change state from regular to chaos. The anti-control methods such as addition of a constant force, of a periodic square wave, of a periodic saw tooth wave, of a periodic triangle wave, of a periodic rectified sinusoidal wave and of the x | x | term are used. The results are illustrated by numerical results, i.e. bifurcation diagram and Lyapunov exponents. Next, chaos synchronization of different order system is studied. Two methods are presented to achieve the synchronization: the addition of the coupling terms, the linearization of the error dynamics. The results are illustrated by phase diagram and time response.

Novel AC-DC and DC-DC converters with a diode-capacitor multiplier

Abstract: This paper presents a transformerless ac-dc and or dc-dc converter with a high output voltage multiplicity, which contains only one switch. The converter consists of an inverter and a diode-capacitor multiplier (DCM) and provides a voltage gain equal to double the number of multiplier steps. In the case of ac-dc conversion the proposed converter offers a practically unit power factor and provides a sine wave input current. The analysis of the steady state as well as the transient behavior of the DCM is given and simplified equivalent circuits are proposed. The prototype of the DCM has been built and tested to show the validity of the proposed converter. The theoretical analysis, the computer simulation results, and the experimental testing results are in good agreement.

A single to three phase matrix converter with a power decoupling capability

Abstract: This paper deals with a new approach for single to three phase matrix converters. In almost all of these converters, three-phase voltages and currents are distorted because of the inherent fluctuation of single-phase instantaneous power. On the contrary, in our proposed matrix converter, that fluctuation is compensated for and three phase voltages and currents can be controlled to be pure sine wave. Our circuit is composed of the conventional single to three-phase matrix converter circuit, an AC reactor and three bi-directional switches. By using the single-phase instantaneous active and reactive power theory (ps-qs theory), the ripple component of the single-phase instantaneous power is detected and is sorted in the AC reactor. Some significant characteristics are verified by means of a simulation with a 200 V/3.7 kW PM motor.

Brushless dc motor driving method and apparatus for it

Abstract: A rectangular wave or a waveform similar to the rectangular wave is output with an conductive angle no less than 120° but no more than 150° during low-speed operation, but output a rectangular wave, a sine wave or a waveform similar to them with an conductive angle no less than 130° but under 180° by changing the frequency only while maintaining the PWM duty constant at high-speed operation, making it possible to realize high-efficiency and low-noise operation at low-speed operation, secure stable high speed, and prevent peak current of effective current because the current waveform also comes closer to sine wave.

Harmonic elimination for multilevel converter with programmed PWM method

Abstract: This work presents a programmed PWM method to eliminate specific higher order harmonics of multilevel converters. First, resultant theory is applied to transcendental equations to eliminate low order harmonics and to determine switching angles for the fundamental frequency switching techniques. Next the magnitudes and phases of the residual higher order harmonics are computed, generated, and subtracted from the original voltage waveform to eliminate these higher order harmonics. The simulation results show that the method can effectively eliminate the specific harmonics, and a low total harmonic distortion (THD) near sine wave is produced. An experimental 11-level H-bridge multilevel converter with a first-on, first-off switching strategy, which is used to balance loads between several levels, is employed to validate the method. The experimental results show that the method can effectively eliminate the specific harmonics, and the output voltage waveforms have less THD than that from the fundamental frequency switching techniques.

Spectrally pure excitation signals: only a dream?

Abstract: For accurate testing of a nonlinear device-under-test (DUT), the spectral purity of the input signal is utterly important. This paper describes a method to create very pure signals, such as sine waves, dual-tones, or multitones, using only power measurements. The signals are generated with an arbitrary waveform generator. Any unwanted spectral line is removed, independent of its exact origin. This allows to apply the correct signal to the DUT, even if the signal source is not perfect or is followed by filters or amplifiers with a small nonlinear distortion. Measurements are used to demonstrate the capabilities of the method.

Enhancement by noise in parallel arrays of sensors with power-law characteristics.

Abstract: An optimally tuned power-law sensor is shown capable of amplifying the signal-to-noise ratio of a sine wave in Gaussian white noise. When associated in parallel arrays, further improvement can be obtained with independent noises injected on these sensors. This form of stochastic resonance in arrays, obtained here with smooth threshold-free nonlinearities, yields signal-to-noise ratio gains above unity in a true regime of added noise for a sine wave in Gaussian white noise, along with a class of nonlinear devices with useful potentialities for noise-aided information processing.

ESPRIT-like estimation of real-valued sinusoidal frequencies

Abstract: Subspace-based estimation of multiple real-valued sine wave frequencies is considered in this paper. A novel data covariance model is proposed. In the proposed model, the dimension of the signal subspace equals the number of frequencies present in the data, which is half of the signal subspace dimension for the conventional model. Consequently, an ESPRIT-like algorithm using the proposed data model is presented. The proposed algorithm is then extended for the case of complex-valued sine waves. Performance analysis of the proposed algorithms are also carried out. The algorithms are tested in numerical simulations. When compared with ESPRIT, the newly proposed algorithm results in a significant reduction in computational burden without any compromise in the accuracy.

Controlled sine wave fitting for ADC test

Abstract: We introduce a novel procedure for testing the dynamic parameters of analog to digital converters (ADC). The test response of the ADC is compared with a reference signal which is supplied by the tester. The evaluation of the parameters is done in time domain in real time. The method has the potential for being very advantageously implemented as a built-in self-test (BIST) into a mixed signal circuit. Goal of the development was to reduce test time significantly compared to the state of the art methods. With regard to a BIST solution another essential requirement was to keep the complexity of the test circuitry as low as possible, to get only a small additional chip area for realization. Both goals were reached successfully. The test time was reduced to a quarter and the number of gates needed is smaller than 6,700. In a first step the algorithm was modeled at system level and the correctness of the procedure was proven by simulations. To get a reliable estimation of the number of gates necessary for an implementation, the optimized model was redesigned in VHDL. Based on the VHDL code a field programmable gate array (FPGA) was configured which led to the gate count estimation. Measurements on a Teradyne J750 tester showed that the accuracy of the method is equivalent to FFT based methods.

Accurate testing of ADC's spectral performance using imprecise sinusoidal excitations

Abstract: Analog to digital converter (ADC) is the world's largest volume mixed-signal circuit. It is also a key building block in nearly all system on chip (SoC) solutions involving analog and mixed-signal functionalities. ADC testing is also crucial for built-in-self-test (BIST) solutions of AMS testing in SoC technology which is identified by the ITRS as one of four most daunting SoC challenges. ADC spectral testing is of critical importance to a large class of integrated circuits and is particularly challenging for high speed and/or high resolutions circuits. In this paper we use spectrally related excitations (SRE) to accurately test the spectral performance of ADCs. Unlike standard approaches, the SRE approach uses low-cost imprecise sine signals as input to the ADC and uses the spectral relationship between multiple input signals to separate distortion inherent in the ADC from that in the input. Efficient DSP algorithms are used to determine the true spectral performance of the ADC. This approach works in both production test and BIST environments. Simulation results show two sine waves with < 60 dB purity can be used to accurately test spectral performance of high resolution ADCs with SFDR in excess of 100 dB. The low-cost SRE signals can be readily generated with simple RC filters with lax band edge requirements. Extensive simulation shows that the algorithm is robust to filter errors, to nonstationary in the test environment, and to measurement noise.

Active electromagnetic device for measuring the dynamic response of a tool in a CNC machine

Abstract: The present invention provides a device for determining the dynamics of a tool sited in a CNC machine, as encapsulated by the Frequency Response Function. The device uses an actively controlled electromagnet to excite forces on the tool. The force is excited in a non-contact manner, allowing the force to be applied to both a stationary and a rotating tool. The displacement is measured by standard means, such as accelerometers, optical displacement or capacitance sensors. The ratio of the force and the displacement in the frequency domain is the Frequency Response Function. The force may be applied as a pure sine wave, providing the Frequency Response Function at the frequency of the sine wave. Varying the frequency of the sine wave provides the Frequency Response Function over the range of frequencies of interest. The control of the force profile is handled entirely by the automated controls and requires no special skills, training or manual interaction by the user. No separate force sensor is required, since the electromagnetic force on the tool may be accurately determined from the design of the electromagnet and the tool position, geometry and material.

Membrane Resonance and Stochastic Resonance Modulate Firing Patterns of Thalamocortical Neurons

Abstract: We examined the interactions of subthreshold membrane resonance and stochastic resonance using whole-cell patch clamp recordings in thalamocortical neurons of rat brain slices, as well as with a Hodgkin-Huxley-type mathematical model of thalamocortical neurons. The neurons exhibited the subthreshold resonance when stimulated with small amplitude sine wave currents of varying frequency, and stochastic resonance when noise was added to sine wave inputs. Stochastic resonance was manifest as a maximum in signal-to-noise ratio of output response to subthreshold periodic input combined with noise. Stochastic resonance in conjunction with subthreshold resonance resulted in action potential patterns that showed frequency selectivity for periodic inputs. Stochastic resonance was maximal near subthreshold resonance frequency and a high noise level was required for detection of high frequency signals. We speculate that combined membrane and stochastic resonances have physiological utility in coupling synaptic activity to preferred firing frequency and in network synchronization under noise.

Analytic approach to the wave packet formalism in oscillation phenomena

Abstract: We introduce an approximation scheme to perform an analytic study of the oscillation phenomena in a pedagogical and comprehensive way. By using Gaussian wave packets, we show that the oscillation is bounded by a time-dependent vanishing function which characterizes the slippage between the mass-eigenstate wave packets. We also demonstrate that the wave packet spreading represents a secondary effect which plays a significant role only in the nonrelativistic limit. In our analysis, we note the presence of a new time-dependent phase and calculate how this additional term modifies the oscillating character of the flavor conversion formula. Finally, by considering box and sine wave packets we study how the choice of different functions to describe the particle localization changes the oscillation probability.

Phase-shift full-bridge high-frequency inverter based on DSP

Abstract: The invented inverter comprises high frequency inversion bridge, high frequency chain transformer, cycle converter, LC alternating current filter, DSP kernel control circuit, MOS tube drive circuit, detection feedback circuit and auxiliary power supply. DSP pure digital control technique is adopted in the invention so as to omit analog circuit such as generation and comparison circuit of triangular and sine wave, analog PID adjuster. The invention has advantages of high-speed computational capability of DSP and powerful integrated peripheral equipment providing features of integrated control, high-integrated level, reduced size and volume, light weight and simple structure.

Abnormality detecting apparatus for rotational angle detecting apparatus

Abstract: PROBLEM TO BE SOLVED: To correctly detect the abnormalities of a rotational angle detecting apparatus that uses a resolver. SOLUTION: The resolver 30 outputs a sine wave phase output signal and a cosine wave phase output signal excited by a sine wave signal, amplitude-modulated, in response to a rotation angle of a rotor 31 to a stator 32 and having amplitude changes with a phase difference of π/2. A sine wave phase amplitude calculating section 61 and a cosine wave phase amplitude calculating section 62 calculate the amplitudes of the sine wave phase output signal and the cosine wave phase output signal. A rotation angle calculating section 63 calculates the rotation angle θ by using the amplitudes. An abnormality determining section 68 tentatively determines an abnormality of the resolver 30, when the square root of the sum of squares of the amplitudes does not lie continuously within a predetermined range, and determines the abnormality of the resolver 30, if such conditions continues further. The abnormality determining section 68 avoids determination of the abnormality, when the calculated rotation angle indicates a rotation of the rotor 31 with respect to the stator 32 as 0 or 2π. COPYRIGHT: (C)2006,JPO&NCIPI

Three-phase pure sinusoidal wave inverse power supply system with digital control

Abstract: The three phases pure sine wave inverter power supply system under total numerical control belongs to inverter power supply field. Its main feature is: the chips of SA4828 for PWM generator, EXB840 for driving circuit and MiniSkip for main circuit are connected in turn under the MPU control; the protective circuit adopts bridge arm parallel connection for resistance, capacitance, diode and inverter; the driving power supply can be gotten from the rectified and filtered output of the high frequency transformer; the MPU employs high volume onchip program and data memory; the high frequency switch IGBT reaches 100KHZ; the driving signal is isolated by opt-couple, the feedback signal is isolated by mutual inductor and transformer; it has test control terminal and can connect to remote computers. It can provide pure sine wave output for communication and power equipment.

Lighting control apparatus

Abstract: A lighting control apparatus of a photographing apparatus comprises a lighting device and a signal supplying processor. The lighting device illuminates a photographic subject by receiving one of a sine wave signal, and a half-wave rectification wave signal, a saw wave signal, and a triangle wave signal in the exposure time. The signal supplying processor supplies one of the sine wave signal, the half-rectification wave signal, the saw wave signal, and the triangle wave signal, to be received, to the lighting device, in the exposure time.

Resonant scanning mirror driver circuit

Abstract: A resonant scanning mirror driver configured to drive a micro-electro-mechanical system (MEMS) mirror to a desired deflection utilizes a PWM pattern selected from patterns having 32, 40, 48, 56 or 64 bits. The patterns reflect the first positive and negative quarters of the PWM pattern and the remaining quarters are generated utilizing the symmetry of the sine wave that is generated.

Apparatus for detecting a distance and apparatus for detecting a body

Abstract: In an apparatus for detecting a distance and improving the SN ratio of received signals, an angular frequency (ω1) of sinusoidal wave signals generated by a sinusoidal wave generator is brought into synchronism with an angular frequency (ω) of burst pulse signals, and signals received by a transmitter/receiver microphone are orthogonally demodulated by using sinusoidal wave signals of the synchronized angular frequency. A microcomputer adds up the vectors of the demodulated signals for only a period of time equal to a section of transmitting the transmission waves from the transmitter/receiver microphone. A distance to a body is detected by using the received signals of which the vectors are added up.

RZ-AMI optical transmitter module

Abstract: Disclosed is an optical transmitter module comprising: a precoder to generate an encoded binary signal from an electric signal; an amplifier to amplify the binary signal; a converter to convert the amplified encoded binary signal into a limited ternary signal; a frequency generator to generate a sine wave having a predetermined frequency; a multiplier to multiply the ternary signal using the sine wave; a light source to generate a coherent CW light having a constant intensity; and a Mach-Zehnder modulator to modulate the CW light according to the ternary signal from the multiplier.

Strong influence of test patterns on the perception of motion aftereffect and position.

Abstract: In a completely linear system, the behavior of a square wave pattern can be predicted by its sinusoidal components. However, we observed a complete breakdown of the linear system prediction in the perception of the motion aftereffect (MAE). The duration of the MAE was measured following a one-minute adaptation to a rotating radial grating. Three different luminance patterns were used for both the adaptation and test stimulus: (1) sine wave, (2) square wave, and (3) complex grating with the same Fourier amplitude spectrum as the square wave, but with randomized phases. The sine wave stimulus generated the highest magnitude MAE, followed by the random-phase complex grating, and lastly the square wave grating. To test whether the square wave grating is a weak adaptor or a weak test for the MAE, we performed a cross adaptation experiment in which the sine wave, square wave, and complex gratings were paired in seven ways. Results show that the strength of the MAE critically depended on the test pattern. Regardless of the adaptor, MAE strength is in a decreasing order with the test pattern as sine wave grating, complex grating, and square wave grating. Further experiments ruled out the possibility that differential MAEs between these conditions are due to different peak contrasts in these patterns. Additionally, the MAE from a square wave grating as the test pattern is not accompanied by a significant concurrent shift in the apparent position. Linear system theory cannot predict the magnitude of the MAE using complex gratings. The spatial features of a test stimulus, such as position reliability or luminance uniformity, strongly influence the magnitude of MAE. Sharp edges and local luminance uniformity can greatly reduce MAE.