Showing papers on "Sine wave published in 1985"

A minimal parameter adaptive notch filter with constrained poles and zeros

Abstract: A new algorithm is presented for adaptive notch filtering and parametric spectral estimation of multiple narrow-band or sine wave signals in an additive broad-band process. The algorithm is of recursive prediction error (RPE) form and uses a special constrained model of infinite impulse response (IIR) with a minimal number of parameters. The convergent filter is characterized by highly narrow bandwidth and uniform notches of desired shape. For sufficiently large data sets, the variances of the sine wave frequency estimates are of the same order of magnitude as the Cramer-Rao bound. Results from simulations illustrate the performance of the algorithm under a wide range of conditions.

Infant Visual Preferences: A Review and New Theoretical Treatment

Abstract: Publisher Summary This chapter focuses on the reason that determines infants' visual preferences at different ages and proposes a quantitative model of preferences based on linear systems techniques and test it against data from several well-known preference experiments The model's predictions agree quite well with observed preferences for a variety of stimuli The success of this model implies that infants' visual preferences are governed simply by a tendency to look at highly visible patterns This account of early preferential looking is thus consonant with the understanding of how the growth of basic sensory mechanisms affects visual perception during the first months of life Linear systems analysis is based on Fourier's theorem This powerful theorem implies that any two-dimensional, time-invariant visual stimulus can be exactly described by combining a set of more basic stimuli These basic stimuli are sine wave gratings A sine wave grating is a pattern of light and dark stripes whose intensity varies sinusoidally with position Sine wave gratings are specified by four parameters—spatial frequency, orientation, phase, and contrast Fourier's theorem implies then that even a complex, two-dimensional visual stimulus, such as the picture of a face, can be described exactly by the combination of a set of gratings of various frequencies, orientations, phases, and contrasts

Mid-rate coding based on a sinusoidal representation of speech

Abstract: In this paper a sinusoidal model for the speech waveform is used to develop a new analysis/synthesis technique that is characterized by the amplitudes, frequencies, and phases of the component sine waves. The resulting synthetic waveform preserves the waveform shape and is essentially perceptually indistinguishable from the original speech. Furthermore, in the presence of noise the perceptual characteristics of the speech and the noise are maintained. Based on this system, a coder operating at 8 kbps is developed that codes the amplitudes and phases of each of the sine wave components and uses a harmonic model to code all of the frequencies. Since not all of the phases can be coded, a high frequency regeneration technique is developed that exploits the properties of the sinusoidal representation of the coded baseband signal. Based on a relatively limited data base, computer simulation has demonstrated that coded speech of good quality can be achieved. A real-time simulation is being developed to provide a more thorough evaluation of the algorithm.

Stabilizing power source apparatus

Abstract: A stabilizing power source apparatus includes a transformer (T3) with one primary (Np) and two secondary coils (Ns), a switching transistor (Q1), first and second differential amplifiers (A,, A2), an oscillator (OSC'), and a pulse modulator (PM). The oscillator generates a triangular wave of variable frequency. The modulator changes the pulse width and frequency of its output in accordance with a shift of a crossing point between the leading ramp of the triangular wave and the signal from the first differential amplifier (A,). The pulse drives the switching transistor (Q,), so that the duty factor of the transistor stabilizes a DC output voltage and a switching frequency thereof stabilizes an AC output voltage. Another stabilizing power source apparatus includes a saturable reactor (Ls1, LS2) for stabilizing the DC output voltage and a resonance type inverter (Lp, O2, Q3, T,, NP1, NP2, ND, Cp) to generate a sinusoidal wave voltage.

Method and apparatus for controlling pwm inverters

Abstract: An AC motor such as an induction motor or a synchronous motor is driven by a PWM inverter circuit. Power switching elements of the inverter circuit are ignited by PWM pulses resulting from comparison of a carrier wave signal with a sine wave modulation signal at a frequency proportional to a frequency setting signal so as to control the inverter circuit. A current polarity detector detects positive and negative components of a DC current flowing in the input side of the inverter circuit. The frequency setting signal is so corrected as to be decreased when only the positive current component flows in excess of one period of the carrier wave signal or increased when only the negative current component flows in excess of the one period.

Pulse width modulated inverter system for driving single phase a-c induction motor

Abstract: A substantially perfect single phase sinusoidal shaped voltage waveform may be generated for driving a single phase a-c induction motor by employing a sinusoidally weighted pulse width modulated signal to switch a pair of solid state power switches on and off in alternation in order to connect the motor alternately across positive and negative power supplies. A low pass filter is effectively connected in series with the single phase motor to filter out all of the signal components except the fundamental of the sine wave modulating frequency. In this way, only a sinusoidal voltage is applied to the motor. By making the switching frequency very high relative to the sine wave modulation component, the filter size and cost are minimized and it is unnecessary to correlate or synchronize the sine wave modulation and switching frequencies.

Bifurcations and chaotic behavior in a simple model of the economic long wave

Abstract: This paper presents a formal stability analysis of a simplified Kondratieff wave model. For normal parameter values the model has a single unstable equilibrium point which, combined with nonlinear constraints in the model's table functions, creates a characteristic limit cycle behavior. For other parameter values, the model generates damped oscillations instead of the limit cycle or overwhelms the nonlinear constraints and exhibits sustained exponential growth or total collapse. By linear stability analysis we first determine the conditions for a Hopf bifurcation, the transition from a stable to an unstable equilibrium. Using global analysis, we outline the phase portrait of a fully developed limit cycle. By the same method we examine the conditions under which the nonlinear functions fail to contain the system so that exponential runaway or collapse occurs. We then develop a DYNAMO program to calculate the Lyapunov exponents of the system during a simulation and discuss how these can be measures of the divergence or convergence of nearby trajectories. Finally, we illustrate how subsequent period doublings and chotic behavior can occur if the model is driven exogennously by a weak sine wave, representing, for instance, the shorterm business cycle.

A minimal parameter adaptive notch filter with constrained poles and zeros

Abstract: A new algorithm is presented for adaptive notch filtering and parametric spectral estimation of multiple narrow-band or sine wave signals in an additive broadband process. The algorithm is of recursive prediction error (RPE) form and uses a special constrained model of proper infinite impulse response (IIR) with a minimal number of parameters. The convergent filter is characterized by highly narrow bandwidth and uniform notches of desired shape. For sufficiently large data sets, the algorithm approaches the Cramer-Rao bound in estimating the frequencies of the sine wave signals.

Effect of skin temperature on vibrotactile sensitivity

Abstract: The vibration problems relating to living bodies have so far been studied from the perspectives of engineering physiology and psychology. This study shows the relationship between vibratory sensibility and temperature in the living body. Psychological experiments were carried out by using the vibrometer of an acoustic calibration apparatus in sine, triangular and square waves. The sensibility-threshold measurements were made using 30–700 Hz sine waves, 30–300 Hz triangular and sawtooth waves, or 30–250 Hz square waves. Each of ten subjects was kept seated. The average value of the vibratory levels, varied by ascending and descending steps, was taken as that of the threshold. As the vibrometer in the apparatus used makes a noise at frequencies greater than 250 Hz it was masked from the subject by presenting him with a different noise. The threshold curve for square waves is lower by 12·3 dB than that for sine waves at about 30Hz. The threshold curve of the 26°C sine wave was lower by 10 dB than that of the 58°C sine wave vibration near 200 Hz. For example with a sine wave, at 58°C the amplitude threshold was lowest at about 270 Hz, but at −11°C at about 200 Hz. At frequency stimulation higher than 120 Hz, as the temperature of the contact point was lowered, the amplitude threshold increased and the frequency at which the threshold curve was at a minimum shifted to a lower frequency.

Nmr gradient field modulation.

Abstract: A circuit and method for providing high, constant amplitude sinusoidally modulated NMR gradient fields. A capacitor (56) is connected in parallel with the gradient coil (54), but separated by a switch (51). A predetermined amount of energy is stored in the capacitor (56) and then the switch (51) is closed to permit a sinusoidal oscillation of energy between the capacitor (56) and gradient coil (54). By precharging appropriately, sine wave or cosine wave oscillation can be obtained for the NMR system. The oscillation is terminated by opening the switch (51) at a time when all of the oscillation energy is in the capacitor (56). In a preferred embodiment of the invention, the switch is a bridge circuit (350), each of whose sides is a back-to-back thyristor pair (352, 354, 356, 358), so that the gradient field may be modulated either as a full wave, half-wave rectified or non-rectified sinusoidal oscillation. In one embodiment, a full-wave rectified sine wave is used, and all the oscillating energy is caught in the capacitor (56) during intervals in which 180o RF pulses are applied to generate echoes. Image data is collected during the sinusoidal oscillation.

Triangle-to-sine wave conversion with MOS technology

Abstract: A description is given of MOS circuit design techniques for nonlinear analog circuits that perform a triangle-to-sine wave conversion. These techniques may also be applied to synthesizing other functions. Design techniques for compensating the conversion for variations in temperature, processing, and triangle wave amplitude are also presented. Results from simulation and monolithic circuit fabrication are reported which show that a sinusoidal approximation with a total harmonic content of 0.2% at 1 kHz is practical. The test circuit is powered from /spl plusmn/5 V supplies and displays a bandwidth of 1.1 MHz.

Energy economizer controlled-current start and protection for induction motors

Abstract: A standard, unmodified induction motor (11) starts with reduced input current, energy consumption and mechanical stress and is further protected from AC power source "phase loss", excessively low or high voltage or a locked-rotor condition during start-up or any subsequent moment while running when its stator winding (13,14,15) is energized from a sine wave source (300) thrkough a signal-responsive wave modifier EET-IC operative to control the portion of each cycle of the sine wave which is coupled from said source to the stator winding. A stator current sampling arrangement (6, 7, 8), and a motor current demodulator responsive to the first few hundred microseconds of stator winding initial inrush current each time said current increases from zero cooperate under certain conditions to produce signals for controlling associated wave modifier means, thereby to achieve a preferred magnitude of motor starting current under rated load conditions and achieve near-optimum motor operating efficiency during start-up and subsequent running with reduced loads and associated motor protection means (4) which inhibits said wave modifier means thereby to de- energise said stator winding under locked-rotor conditions that occur when motor start-up is attempted or later when the motor is running, or an AC power source anomaly occurs which would otherwise cause start-up stalling, excessive motor running current or motor stalling under rated loads.

Digital PWMed pulse generator

Abstract: Plural series of digital pattern data are determined by PWMing a sine wave by a triangular wave and further classified into each series by the number of triangles included within a half cycle of the sine wave. An appropriate series of data are selected according to a frequency command. The selected data are further adjusted in response to a voltage control command. On the basis of the selected and adjusted pattern data and in response to a half period signal of triangular wave and triangle slope signals, a PWMed pulse is generated through a logical circuit. In the case where the generator is incorporated with an induction motor driving system, it is possible to control speed (frequency), torque (voltage), rotational directions, and torque fluctuations (phase difference) of an induction motor accurately at high response speed.

Errors in Sampled Data Phase Measurement

Abstract: Synchronous real-time sampling can be used to measure the phase angle ? between two sine waves in a relatively low-frequency range. The data samples are acquired by a microcomputer-based system, then manipulated to determine ?. The system uses less hardware than a traditional phase meter, however there will be an error in ? due to mislocating the zero-crossings of the two sine waves. An error analysis is given, which indicates that errors mainly depend on signal amplitudes, number of quantization bits, and number of samples per cycle. Also, numerical results are illustrated.

Pulse width modulated inverter system for driving single phase a-c induction motor at a constant voltage/frequency ratio

Abstract: A sinusoidally weighted pulse width modulated switching signal may be developed, for operating an inverter to apply sinusoidal voltage to a single phase a-c induction motor, by comparing a triangular voltage waveform of fixed frequency with a variable frequency sine wave voltage, the switching signal varying between its high and low states whenever the triangular waveform and modulating sine wave intercept one another. A constant ratio of the amplitude of the sinusoidal motor voltage relative to the voltage's frequency, and thus motor speed, may be obtained simply by translating the sinusoidal modulating waveform through a high pass filter before it is compared with the triangular wave. By setting the filter cut-off frequency above the operating frequency range (preferably from about 12 to 60 hertz) of the sine wave generator, the sine wave voltage will be attenuated by the filter in an amount inversely proportional to the sine wave frequency. In this way, the amplitude of the sine wave will vary in step with, and directly proportional to, frequency changes to achieve a constant motor voltage/frequency ratio.

Method and apparatus for volume measurement

Abstract: A method of measuring the volume (V) of a gas in a container (20) comprises varying the container volume according to a sine wave between a minimum and a maximum value, the variation being made at a constant frequency but at varying amplitude, to obtain a predetermined pressure difference (DELTAp), and the volume difference (DELTAV) corresponding to said predetermined pressure difference (DELTAp) being determined by detecting the points of time when at least two points on the sine wave are attained which correspond to two predetermined values of the container volume. By measuring the time between the two points on the sine wave, the sine wave peak values for the volume difference (DELTAV) corresponding to said predetermined pressure difference (DELTAp) may be calculated and, thus, the said volume difference (DELTAV). By means of the formula V=DELTAVxpOx$(1,4)$/DELTAp, wherein PO = the static pressure and $(1,5)$= Cp/Cv wherein Cp and Cv are the specific heat capacity at, respectively, constant pressure and constant volume for the gas within the container, the gas volume (V) in the container may then be determined. An apparatus for carrying the method into effect has also been constructed.

Method for driving a bender-type transmitter of a borehole logging tool to sequentially produce acoustic compressional and tube waves

Abstract: An acoustic well logging system employs a sine wave tone burst generator which drives a bender-type transmitter in a borehole logging tool to sequentially produce acoustic compressional and tube waves. A sine wave tone burst is selectively swept or fixed in frequency between 10 kHz and 1.5 kHz to generate a constant frequency compressional wave and below 1.5 kHz to generate a constant frequency tube wave. The constant frequency of the compressional wave along a particular subsurface formation interval is characteristic of the rock material of such subsurface formation interval.

Position indicating apparatus for use in a digitizing tablet system

Abstract: A position indicating implement is disclosed having a first coil connected to a current source and a second coil inductively coupled with the first coil. A capacitor is connected in series with the second coil so that the current in the first coil induces a phase shifted current in the second coil. A tip extends from the barrel of the position indicating implement of the present invention. The tip is designed for placement on and movement over a digitizing tablet. A switch has been located near the tip so that it is easily accessible to a user's finger while holding the implement. The power source providing an alternating current to the first coil includes a digital switching circuit for producing a step function which approximates a sine wave and lacks any components at the second, third, fourth, fifth and sixth harmonics. The step function is filtered to produce a sine wave for delivery to the first coil. The switch near the tip of the implement may be used as a mouse switch so that the position indicating implement may be used as a mouse to indicate relative position rather than absolute position. Remote signaling may be accomplished by providing a switch in the circuit of the second coil. Calibration of the phase shift between the fields of the two coils may be accomplished by providing a line from the circuit of the second coil.

ALE behavior for two sinusoidal signal models

Abstract: The adaptive line enhancer (ALE) weight covariance matrix is determined for a complex monochromatic sine wave signal in an independent circular Gaussian noise background. The weight covariance matrix is shown to differ significantly from that obtained when the signal is a narrow-band sine wave process. In spite of this result, the misadjustment factors which characterize the mean-norm squared error behavior of the ALE are essentially indistinguishable for small values of the adaptation parameter-noise power product (μσ2).

Video disc record

Abstract: PURPOSE:To detect jitter at an optional period by recording superimposingly a pilot signal of a constant frequency on a disc record to an information signal formed through FM modulation of a broad band video signal. CONSTITUTION:A high definition video signal is inputted to a band compression encoder 1 and converted into a broad band video signal in 8.1MHz by using a clock lead by a fixed oscillation circuit 2 in 64.8MHz. The video signal is inputted to an FM modulation circuit 3. The video signal is inputted to an FM modulation circuit 3, the carrier frequency shift region is converted into an information signal having 14-16MHz carrier frequency region, and inputted to the 1st band pass filter 4 taking the frequency shift region and the 1st lower side band in 4-17MHz as the pass band. On the other hand, a 1/256 frequency division circuit 5 inputting the clock signal leads out the frequency division output of 15fH/2 (fH is horizontal synchronizing frequency). This frequency division output is inputted to a low pass filter 6, waveform-shaped into a sinusoidal wave and led out as a pilot signal.

Method and circuit for producing sinusoidal waves having harmonic elimination from 2π periodical square waves

Abstract: A method for producing sinusoidal waves uses the steps of generating a plurality of clock signals during a 2π period, using the clock signals to control the generation of 2π periodical square wave pulses having preselected length and phase relationships during respective ones of the clock signals and applying the square wave pulses to a low pass filter. The reduction of pulse length as well as the phase relationship of the pulses is evaluated from a system of equations by setting the odd harmonics of corresponding Fourier series to zero or to a predetermined minimum value. A circuit device utilizing this method uses a switching amplifier operated in a binary sequence having a period corresponding to the desired sine wave period and a low pass filter connected to the output of the amplifier. A clock oscillator having a clock frequency higher than the frequency of the desired sine wave controls the amplifier via a sequencer having a counter stepped by the oscillator with the counter outputs being applied to the switching amplifier through a logic circuit.

Digital spectrum analyzer

Abstract: PURPOSE:To measure even a transfer characteristic having a large level change with high precision by generating a test signal for each measuring frequency range divided in plural areas and setting the input level of an AD converter to compensate the conversion output CONSTITUTION:First, a noise signal is given to an object 12 to be measured to measure all measuring bands F0-Fn, and a general transfer function characteristic is obtained This characteristic is divided to parts, where the level change for frequency is sharp, and parts where it is slow, and the noise signal is set as the test signal to an FFT analyzer 14 in case of areas from the band F0 to the band F1 and from the band F2 to the band Fn, and a single sine wave signal is set as the test signal to the analyzer 14 in case of the area from the band F1 to the band F2 Next, the set test signal is supplied from a test signal generator 11 to the object 12 to be measured, and the input level of the AD converter in the analyzer 14 is set to perform FFT analysis, and the convertion output is compensated in accordance with range setting The transfer function of the object 12 to be measured is measured in accordance with the input test signal of the object 12 to be measured and the Fourier conversion output of the output test signal

Controller of induction motor for vehicle

Abstract: PURPOSE: To always normally operate even if a battery voltage varies by correcting an AC command signal in response to the detected values of a battery voltage. CONSTITUTION: Coefficient generators 45, 47 output coefficients γ,λ in response to the speed signal ω of an induction motor 5. A correcting coefficient μ in response to the voltage of a battery 1. A multiplier 51 multiplies a correction signal produced by multiplying the coefficient γ by the correcting coefficient μby a coefficient A' in response to a torque signal A from an accelerator 13, and outputs a voltage command signal V. A multiplier 53 multiplies a coefficient A" in response to a torque signal A by the coefficient A", and outputs a frequency command signal ωs. A 3-phase sinusoidal wave generator 21 outputs a 3-phase sinusoidal wave signal in response to the signals V and ωs. Comparators 25, 27, 29 compare the 3-phase sinusoidal wave signal with a triangular wave, and supplies a pulse width modulation signal to an inverter 3. COPYRIGHT: (C)1986,JPO&Japio

Correcting device for error in measured angle

Abstract: PURPOSE:To obtain a real measured angle value easily by correcting a measured angle value including an error on on-line basis according to various constants regarding error factors calculated by Fourier analytic calculation on the basis of a previously sampled measured angle value. CONSTITUTION:A subslit plate 23 which rotates coaxially with the axis of rotation of a main slit 1 is arranged opposite extremely closely to the main slit 1. A diffracted image scanned by a subslit 2 for a cosine wave and a subslit 3 for a sine wave at the peripheral edge part of the subslit plate 23 is converted photoelectrically by photodetecting elements 4 and 5 to generate the cosine and sine wave signals. A couple of the 1st correctors 7 and 8 receive and process DC component in an acutally measured wave from memory 6. Further, a constant calculating device 11 receives a phase error from the memory 6 to output a constant (a), and a couple of the 2nd correctors 9 and 10 correct the outputs of the 1st correctors. Their outputs are inputted to an angle calculating device 12 to outputs a real angle, which is displayed on a display device 13.

Radio direction finder

Abstract: PURPOSE:To display the arrival direction and elevation of a radio wave and the distance to a radio wave emitting point, by measuring the arrival direction and amplitude value of the phase change component of a receiving signal obtained by arranging a non-directional antenna and comparing both of them with reference values. CONSTITUTION:A frequency correction circuit 6 converts an azimuth signal, of which the amlitude changes in proportion to frequency, to an azimuth signal with constant amplitude regardless of frequency and an internal signal circuit 8 generates a rectangular wave group comprising the relation of frequency same to and integer times to that of the azimuth signal. A reference signal generation circuit 2 generates a SIN wave synchronous to the internal output signal and multiplies the same by both rectified waves of the azimuth signal to integrte the area of the product output signal thereof on the basis of a polarity signal. The phase of the internal output signal is controlled by this integrated result and follows that of the azimuth signal while the sum total of preset values F4 come to a radio wave arrival direction. When the azimuth of a radio wave is determined, the amplitude of an azimuth is calculated and compared with the content 11 of memory 10 while an azimuth, elevation and a distance of values coincided with or nearest to said amplitude value are displayed by an azimuth display device 12.

Method and apparatus for analysing geophones

Abstract: Method of analysing geophones, comprising sending electric currents through the geophones and deriving desired parameters from the output voltages and/or currents. One string of geophones is used as a reference which compensates influences of temperature. A calibration measurement can be carried out on a precision ohmic resistor. Applied on geophones which have a high damping a negative resistance network is coupled in parallel to the geophone terminals. The pulse response test is used to derive sensitivity, damping and resonance frequency, and to calculate the DC resistance. Distortion tests are carried out on the basis of sine wave currents sent through the geophone(s). The invention also includes an apparatus for performing the method. The apparatus is advantageously microprogram-based.