Showing papers on "Sine wave published in 2000"

Properties of the IEEE-STD-1057 four-parameter sine wave fit algorithm

Abstract: The IEEE Standard 1057 (IEEE-STD-1057) provides algorithms for fitting the parameters of a sine wave to noisy discrete time observations. The fit is obtained as an approximate minimizer of the sum of squared errors, i.e., the difference between observations and model output. The contributions of this paper include a comparison of the performance of the four-parameter algorithm in the standard with the Cramer-Rao lower bound on accuracy, and with the performance of a nonlinear least squares approach. It is shown that the algorithm of IEEE-STD-1057 provides accurate estimates for Gaussian and quantization noise. In the Gaussian scenario it provides estimates with performance close to the derived lower bound. In severe conditions with noisy data covering only a fraction of a period, however, it is shown to have inferior performance compared with a one-dimensional search of a concentrated cost function.

Biomedical Signal Processing and Signal Modeling

Abstract: The Nature of Biomedical Signals. Memory and Correlation. The Impulse Response. Frequency Response. Modeling Continuous-Time Signals as Sums of Sine Waves. Responses of Linear Continuous-Time Filters to Arbitrary Inputs. Modeling Signals as Sums of Discrete-Time Sine Waves. Noise Removal and Signal Compensation. Modeling Stochastic Signals as Filtered White Noise. Scaling and Long-Term Memory. Nonlinear Models of Signals. Assessing Stationarity and Reproducibility. Appendix.

Ultrasonic surgical equipment

Abstract: PROBLEM TO BE SOLVED: To monitor an output frequency easily in a frequency range that corresponds to a resonance frequency in every treatment instrument for a plurality of treatment instruments. SOLUTION: DDS 11 reads in a set frequency from CPU 10. After DDS 11 reads in the set frequency information, it calculates a monitoring frequency range on the basis of such information. Then it outputs a sine wave to an amplifier part 12 according to the set frequency. Thereafter, DDS 11 calculates a finite difference between the set frequency and the output frequency to seek a frequency deflection. Then, DDS 11 compares such calculated frequency deflection and the monitored frequency.

Motor control device and motor control method

Abstract: A motor current detection amplifier detects a motor current's areas in two phase periods with reference to a motor voltage. A controlling microcomputer computed the ratio of the motor current areas of the two phase periods and provides the same as phase difference information which is in turn used to control a motor drive voltage to apply a sine wave of a predetermined period to the motor's coil to allow 180°-driving including a sine wave conduction resistant to noise and achieving a reduced cost hike.

Spurious signals in direct digital frequency synthesizers due to the phase truncation

Abstract: Direct digital frequency synthesizers (DDS or DDFS) are widely used in modern communications and measurement devices. Their advantages are small size and power consumption together with excellent frequency stability, high frequency resolution, and short switching times. The difficulties are rather low output frequencies (500 MHz at the present state of the art) and a large set of the spurious signals very often above the -80 dB level. One source of spurious signals in DDS is the use of smaller number, W, of the most significant bits (MSB) applied for the output sine wave reconstruction from all R bits stored in the accumulator. The result is a phase modulation of the output signal. The problem was first solved in a rather complicated way with the result that the level of the largest spurious signal is about -6 W dB below the carrier with an increase of 3.9 dB in some instances. A simpler solution of the problem of spurious signal level due to the phase truncation in DDS was found earlier. However, no attention was paid to the validity of the corrections suggested. In this paper we will be concerned with this problem and investigate the validity and correctness of these generally cited results and provide a simple way for finding positions, levels, and numbers of these spurious signals generated by truncation to W bits of the phase information stored in the DDS accumulator memory of R bits (W

Nonlinear short-wave propagation in ferrites

Abstract: In this paper we discuss the propagation of nonlinear electromagnetic short waves in ferromagnetic insulators. We show that such propagation is perpendicular to an externally applied field. In the nonlinear regime we determine various possible propagation patterns: an isolated pulse, a modulated sinusoidal wave, and an asymptotic two-peak wave. The mathematical structure underlying the existence of these solutions is that of the integrable sine-Gordon equation.

Low harmonic distortion in a Josephson arbitrary waveform synthesizer

Abstract: The use of broadband integrated filters has enabled practical operating margins for ac waveforms synthesized from the perfectly quantized voltage pulses of Josephson junction arrays. This improvement enabled the digital synthesis of arbitrary waveforms with low harmonic distortion; the second and higher harmonics are all at least 94 dB below the fundamental [−94 dBc (carrier)]. This is a 47 dB lower distortion compared to that of the same sine wave synthesized by the semiconductor-based code generator which drives the array. We present operating margins for synthesized dc voltages and demonstrate synthesized waveforms with multiple tones at kilohertz and megahertz frequencies with harmonic distortion and intermodulation products below −80 dBc.

Constrained force control of shape memory alloy actuators

Abstract: Experimental results are presented to show that SMA actuators are able to control forces both rapidly and precisely. An antagonistic pair of constrained actuators is shown to be capable of rapidly changing the set-point throughout a /spl plusmn/7.00 N range. Although the system entered into a limit cycle at the set-point, the limit cycle magnitude was small. The peak to peak amplitude of the limit cycles was only 0.07 N with a worst case average offset of 0.016 N at high force rates up to 75 N.s/sup -1/. Simulation results also indicate that accuracy could be improved with an increased sampling rate. The SMA actuator pair was also shown to be capable of accurate tracking. The maximum tracking error for a f=0.500 Kz, 2.00 N sine wave was 0.04 N. For the 2 Hz tracking, the maximum error was approximately equal to the boundary layer width which was set at 0.30 N.

Matched filter, filtering method and digital broadcast receiver using the same

Abstract: A digital passband matched filter is automatically adapted to a carrier wave ω in accordance with a frequency offset of the carrier wave, to obtain a passband digital signal having no frequency distortion due to the frequency offset. Thus, a receiver in which drawbacks such as decrease of SNR and increase of circuit complexity caused by the fixed baseband/passband matched filter is obtained. Since a cosine wave generating section operates in a carrier wave frequency restoring mode and a carrier wave frequency adaptive mode, respectively, a single cosine wave ROM table can be used regardless of the respective operating modes, thereby reducing circuit complexity. Since the digital passband matched filter acts to renew the filter coefficients adapted to the carrier wave adaptive mode only, power consumption required to operate the filter can be minimized.

Variable low frequency offset, differential, OOK, high-speed twisted pair communication

Abstract: A method and system for transmitting data over twisted pair copper wires using a low frequency offset, differential voltage, on-off keying (OOK) transmission technique are described. According to one embodiment, an analog or digital signal is sent or received and converted, if necessary, into or from serial format onto or out of a twisted pair. The signal uses an OOK modulated sinusoidal offset signal with an associated differential voltage. A floating reference ground set positive or negative for the differential nature of the transmission may be required. The OOK modulated offset low frequency is being keyed to the floating ground reference that is set to a minimum signal to noise ratio (SNR) level. The SNR level may be set by adjusting the voltage separation between floating ground and the offset of the sinusoidal low frequency wave. The amplitude of the sinusoidal wave may be adjusted to provide increased transmission distance and better SNR. In addition, an encoding scheme may be used to incorporate all signaling and control information within the serial transmission. Next, the transmitted signal is input into a coupler that interfaces it to the twisted pair network. At the far end, a decoupler receives the transmission and sends the OOK sinusoidal signal out to designated amplifiers to provide voltages needed for activating an OOK detection system. The OOK detection system may use current detection that is activated every time the designated OOK signal frequency is received. Clocking may be recovered using a digital phase lock loop. Further, the OOK signal is decoded and information split off to designated leads. Afterwards, the recreated square wave transmission serial bit stream is converted to compatible signaling voltages and sent to a digital computer interface.

Power factor compensation device for motor driving inverter system

Abstract: The present invention relates to a power factor compensation device for a motor driving inverter which can improve a power factor of a voltage and a current inputted to the inverter driving a motor. The present invention detects a zero crossing point of an utility alternating current power, and outputs a driving signal corresponding to a plurality of sine wave form voltage values stored in a memory according to a detection result, when the zero crossing point of the utility alternating current power is detected in a state where the plurality of sine wave form voltage values corresponding to a voltage of the utility alternating current power and frequencies are stored in the memory. A switching transistor is switched according to the driving signal, and the voltage applied to the inverter is switched according to the switching operation, thereby improving the power factor.

Controller for inverter for drive of motor

Abstract: PROBLEM TO BE SOLVED: To provide a controller for a motor which does not much affect efficiency even if ripple occurs sharply, and an inverter for drive of the motor, which controls the currents of the d and q axes of the motor so that the the input current i may become sine waves as far as possible by letting a current ed contain ripple intentionally and controlling it. SOLUTION: This controller for an inverter for drive of a motor improves the input power factor of a diode full wave rectifying circuit 2 and the waveform, by controlling the torque of a motor 5 in advance, with the frequency double the power source, by means of a single-phase diode full wave rectifying circuit 2 which receives the input of a single-phase AC power source 1, a small- capacity smoothing capacitor 3 about one hundredth the smoothing capacitor for a conventional diode full wave rectifying circuit connected to this, and 8 control circuit 6 composed of a PWM inverter circuit 4 for control and a motor 5.

Variable output induction motor drive system

Abstract: A variable output induction motor drive system for use with a polyphase variable output alternating current motor including a rotor and stator to drive an operating load such as an automotive vehicle, the variable output induction motor drive system comprises a sine wave current generator operatively coupled to a direct current power source to receive direct current therefrom and to generate a variable sine wave current and operatively coupled to the polyphase variable output alternating current motor to selectively feed the variable sine wave current thereto and a sine wave current control coupled between the sine wave power current generator and the polyphase variable output alternating current motor to monitor the operating parameters of the polyphase variable output alternating current motor and to control the amplitude and frequency of the variable sine wave current fed from the sine wave current generator to the polyphase variable output alternating current motor to control the output torque and speed thereof.

Incremental rotary encoder for measuring horizontal or vertical angles

Abstract: An incremental rotary encoder outputs two sine wave signals having a phase difference of 90 degrees when the incremental rotary encoder is in operation, the incremental rotary encoder including a binary coding circuit which codes each of the two sine wave signals into a binary signal, a voltage detector which detects the voltage of one of the two sine wave signals at the moment of variation in a signal level of the binary signal, and a controller which includes a calculator which takes an even number of voltage values from each of the two sine wave signals to take an average of the even number of voltage values for each of the two sine wave signals.

Ground resistance monitor

Abstract: A permanently mounted AC powered control/display unit and a remote sensor for use in measuring ground resistance. The sensor is permanently mounted around the earth grounding cable. The control display unit generates a 1953 Hz, 5 Vac sine wave which is sent via a cable to a 100:1 ratio drive transformer in the remote sensor. The transformer induces a 0.05 Vac sine wave in the ground cable. The resulting current is detected by a 100:1 turns ratio sense transformer. The current is returned via the cable to the control display unit and converted to a voltage, filtered, amplified and rectified by a synchronous rectifier. The rectified voltage is again filtered and presented to an analog to digital converter. A microprocessor reads the output of the analog to digital converter and the ground resistance is computed by using Ohm's Law (R=E/I), the result being shown on a display.

Method and apparatus for modulating a signal

Abstract: A modulated signal ( 10 ) is sinusoidal wave signal wherein each half wave cycle carries a digital data value associated with an amount of its amplitude. A positive half wave cycle with an amplitude of M encodes a binary level zero digital data value while a positive half wave cycle with an amplitude of M+x encodes a binary level one digital data value. Similarly, a negative half wave cycle with an amplitude of −M encodes a binary level zero digital data value while a negative half wave cycle with an amplitude of −M−x encodes a binary level one digital data value. The positive and negative half wave cycles may transport dual portions of a channel at the same frequency as a modulated signal ( 20 ) for either a dual transmission capability or as a full duplex bidirectional transmit/receive channel. Each half wave cycle may also be modulated to carry a plurality of digital data values beyond binary level zero and one through selection of four or more amplitude levels to generate a modulated signal ( 30 ). A modulated signal ( 40 ) may also provide digital data value representations in each quarter wave of the sinusoidal wave signal to further increase bandwidth capability.

Brain-wave representation of words by superposition of a few sine waves

Abstract: Data from three previous experiments were analyzed to test the hypothesis that brain waves of spoken or written words can be represented by the superposition of a few sine waves. First, we averaged the data over trials and a set of subjects, and, in one case, over experimental conditions as well. Next we applied a Fourier transform to the averaged data and selected those frequencies with high energy, in no case more than nine in number. The superpositions of these selected sine waves were taken as prototypes. The averaged unfiltered data were the test samples. The prototypes were used to classify the test samples according to a least-squares criterion of fit. The results were seven of seven correct classifications for the first experiment using only three frequencies, six of eight for the second experiment using nine frequencies, and eight of eight for the third experiment using five frequencies.

R/D converter

Abstract: There is provided an R/D converter capable of realizing a high speed response. When a sine wave for excitation of a resolver is a positive (or negative) maximum value, an AD converter makes AD conversion of a sine-wave output and a cosine-wave output of the resolver and makes input to a DSP. The DSP calculates on the basis of the input data, and outputs an obtained digital value to a DA converter and the like. Since the DSP calculates a rotor shaft angle, as compared with prior art (R/D converter of a tracking system) which includes a close loop made up of a demodulator circuit, a voltage controlled oscillator, and the like, and carries out a kind of PLL control, it becomes possible to carry out rotor shaft angle calculation at higher speed, and the high speed response can be realized by this. Since the rotor shaft angle is obtained through a digital operation, a compensation circuit of temperature drift, which has been required in the prior art, becomes unnecessary, and by that, the whole structure becomes simple, and the cost can be reduced.

Neural Network Modelling with Input Uncertainty: Theory and Application

Abstract: It is generally assumed when using Bayesian inference methods for neural networks that the input data contains no noise. For real-world (errors in variable) problems this is clearly an unsafe assumption. This paper presents a Bayesian neural network framework which accounts for input noise provided that a model of the noise process exists. In the limit where the noise process is small and symmetric it is shown, using the Laplace approximation, that this method adds an extra term to the usual Bayesian error bar which depends on the variance of the input noise process. Further, by treating the true (noiseless) input as a hidden variable, and sampling this jointly with the network's weights, using a Markov chain Monte Carlo method, it is demonstrated that it is possible to infer the regression over the noiseless input. This leads to the possibility of training an accurate model of a system using less accurate, or more uncertain, data. This is demonstrated on both the, synthetic, noisy sine wave problem and a real problem of inferring the forward model for a satellite radar backscatter system used to predict sea surface wind vectors.

A broadband high-voltage SLIC for a splitter- and transformer-less combined ADSL-Lite/POTS linecard

Abstract: A monolithic broadband subscriber line interface circuit (B-SLIC) has been integrated in the smart power technology SPT170B, combining the functionality of an analog 150-V ringing SLIC with that of a line driver for ADSL-Lite data signals. Thus the B-SLIC is the key circuit for the realization of a very compact integrated voice data (IVD) central office linecard that neither needs analog filters ("POTS-splitter") nor transformers or relays. In spite of the fundamental voltage/frequency tradeoff, the B-SLIC is able to feed high dc or ring voltages to the line, while simultaneously acting as voice and data transceiver. Total harmonic distortion values are below -60 dB even for a high 25-V/sub pp//550-kHz sine wave signal into a 200 /spl Omega/ load; ADSL-signal-based multitone power ratio (MTPR) measurements also yield results better than 60 dB. Power dissipation in simultaneous voice and data operation is about 2.2 W.

Wavelet analysis of signals and images, a grand tour,

Abstract: We review the general properties of the wavelet transform, both in its continuous and its discrete versions, in one or two dimensions, and we describe some of its applications in signal and image processing. We also consider its extension to higher dimensions and to the space-time context, for the analysis of moving objects. 1. MOTIVATION: WHAT IS WAVELET ANALYSIS? Wavelet analysis is a particular timeor space-scale representation of signals which has found a wide range of applications in physics, signal processing and applied mathematics in the last few years. In order to get a feeling for it and to understand its success, let us consider first the case of one-dimensional signals. It is a fact that most real life signals are nonstationary. They often contain transient components, sometimes very significant physically, and mostly cover a wide range of frequencies. In addition, there is frequently a direct correlation between the characteristic frequency of a given segment of the signal and the time duration of that segment. Low frequency pieces tend to last a long interval, whereas high frequencies occur in general for a short moment only. Human speech signals are typical in this respect. Vowels have a relatively low mean frequency and last quite long, whereas consonants contain a wide spectrum, up to very high frequencies, especially in the attack, but they are very short. Clearly standard Fourier analysis is inadequate for treating such signals, since it looses all information about the time localization of a given frequency component. In addition, it is very uneconomical. If a segment of the signal is almost flat, i.e., uninteresting, one still has to sum an infinite series for reproducing it. Worse yet, Fourier analysis is highly unstable with respect to perturbation, because of its global character. For instance, if one adds an extra term, with a very small amplitude, to a linear superposition of sine waves, the signal will barely be modified, but the Fourier spectrum will be completely perturbed. This does not happen if the signal is represented in terms of localized components. Therefore, signal analysts turn to time-frequency (TF) representations. The idea is that one needs two parameters. One, called a, characterizes the frequency, the other one, b, indicates the position in the signal. This concept of a TF representation is in fact quite old and familiar. The most obvious example is simply a musical score! If one requires, in addition, the transform to be linear, a general TF transform will take the form: s(x) 7→ S(b, a) = ∫ ∞ −∞ ψba(x) s(x) dx, (1.1) where s is the signal and ψba the analyzing function (we denote the time variable by x, in view of the extension to higher dimensions). Within this class, two TF transforms stand out as particularly simple and efficient, the windowed or short time Fourier transform (STFT) and the wavelet transform (WT). For both of them, the analyzing function ψba is obtained by a group action on a basic (or mother) function ψ, only the group differs. The essential difference between the two is in the way the frequency parameter

Ultra-wideband pulse coincidence beamformer

Abstract: An ultra-wideband beamformer is provided by using conventional phase shifting techniques to impress data and antenna scan information onto a narrow band signal. A non-linear element then converts the narrow sine wave into ultra-wideband pulses. Phase shift key modulation impresses data information onto the sine wave in the form of a phase shift. The data-bearing sine wave is split into multiple transmission lines where each provides an additional antenna scanning phase shift. The non-linear element converts each phase of the sine wave into short pulses which are sent to radiating elements for transmission. In the far-field of the beam, the scan delays between the radiating elements are canceled out, such that the fields from each radiating element are summed and the pulse position modulated data recovered.

Method and apparatus for torque ripple reduction in sinusoidally excited brushless permanent magnet motors

Abstract: A method for determining a dimension in a motor is described. By applying Fourier analysis, a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle δ is described, wherein the fifth harmonic term of the sequence of terms is minimized. An electric motor having a rotor and a set of slot on said rotor surface having a set of magnets with a width δ along the circumference of said rotor surface is described. The width δ is determined by a method that includes applying Fourier analysis thereby a sequence of terms is obtained. Since the fifth harmonic is the most undesirable term, the minimization of the fifth harmonic term will make resultant waveform closer to sine wave. Based upon the above, a determination of an angle δ is described, wherein the fifth harmonic term of the sequence of terms is minimized.

Centrifugal unbalance detection system

Abstract: A system (10) consisting of an accelerometer sensor (14) attached to a centrifuge enclosure (12) for sensing vibrations and outputting a signal in the form of a sin wave with an amplitude and frequency that is passed through a pre-amp (15) to convert it to a voltage signal, a low pass filter (16) for removing extraneous noise, an A/D converter (21) and a processor (17) and algorithm for operating on the signal, whereby the algorithm interprets the amplitude and frequency associated with the signal and once an amplitude threshold has been exceeded the algorithm begins to count cycles during a predetermined time period and if a given number of complete cycles exceeds the frequency threshold during the predetermined time period, the system shuts down the centrifuge.

Evolution of the optimum bidirectional (+/- biphasic) wave for defibrillation.

Abstract: Introduction of the asymmetric bidirectional (+/- biphasic) current waveform has made it possible to achieve ventricular defibrillation with less energy and current than are needed with a unidirectional (monophasic) waveform. The symmetrical bidirectional (sinusoidal) waveform was used for the first human-heart defibrillation. Subsequent studies employed the underdamped and overdamped sine waves, then the trapezoidal (monophasic) wave. Studies were then undertaken to investigate the benefit of adding a second identical and inverted wave; little success rewarded these efforts until it was discovered that the second inverted wave needed to be much less in amplitude to lower the threshold for defibrillation. However, there is no physiologic theory that explains the mechanism of action of the bidirectional wave, nor does any theory predict the optimum amplitude and time dimensions for the second inverted wave. The authors analyze the research that shows that the threshold defibrillation energy is lowest when the charge in the second, inverted phase is slightly more than a third of that in the first phase. An ion-flux, spatial-K+ summation hypothesis is presented that shows the effect on myocardial cells of adding the second inverted current pulse.

Method and device for driving an AC load, especially an AC motor with speed control

Abstract: of EP1073192The ac motor has a Sine wave input (Un) that is rectified an sent to the drive stage (2). At the same time the zero cross over point is detected and fed into the controller (6) together with the speed setting (14) zero cross over detection (10) signal of the current to the motor load (L).