Showing papers on "Sine wave published in 1982"

Finite amplitude method for the determination of the acoustic nonlinearity parameter B/A

Abstract: The acoustic nonlinearity parameter B/A is determined using a method based on the finite amplitude distortion of a sine wave emitted by a piston. We measure the growth of the second harmonic component of this wave using a piston receiver, which is coaxial with and the same size as the source. In order to determine B/A, the experimental measurements are compared to a theory which incorporates the nonlinearity parameter. The theory developed for this study accounts for the influence of both diffraction and attenuation on the experimental measurements. For this reason, the method is more accurate than previous techniques that employ plane wave theory for a lossless medium. To test the measurement method, we compare the experimental results for B/A in distilled water, ethylene glycol and glycerol to established values. The agreement between these values suggests that the measurement accuracy is plus or minus 4% for common liquids. [Work supported by ONR.]

Transmitter/receiver circuit for signal transmission over power wiring

Abstract: A system transmits and receives control signals for various types of indoor devices using the existing power wiring in houses and buildings. The transmitter section of the power wiring transmission system is provided with a circuit in which the output of a sine wave oscillator is fed to an emitter-follower through a photocoupler and this output is then fed to the indoor power distribution line through a series resonance circuit after stepping down with a transformer; and the receiving section is provided with a circuit in which the signal from the distribution line is fed to a parallel resonance circuit after passing through a series resonance circuit. Moreover, the input and output sections are resistor terminated.

Method and apparatus for objective determination of visual contrast sensitivity functions

Abstract: A method and apparatus for objectively determining the visual contrast sensitivity function of a human subject involves subjecting the vision of the human subject to a plurality of sine wave gratings differing in spatial frequency and contrast levels. As the subject views the grating patterns on a video monitor, the brain wave activity of the subject is detected and steady state Fourier spectra of the activity are recorded. In each spectrum corresponding to a grating pattern of a particular spatial frequency, a visual evoked potential component may be distinguished from noise by adjusting the contrast level of the grating pattern. A contrast threshold used in deriving the visual contrast sensitivity function is identified for each grating pattern of a particular spatial frequency by pinpointing the contrast level at which the visual evoked potential component becomes indistinguishable from noise in the spectrum.

Phase shift type linear position detection device

Abstract: About a bobbin, there are wound primary coils in axially displaced locations and wound also is a secondary coil. A core is linearly slidably provided in the bobbin. The primary coils are individually excited by AC signals which are out of phase with each other, e.g. a sine wave signal and a cosine wave signal. The secondary coil thereupon produces an output signal resulting from phase shifting the applied sine or cosine wave signal in accordance with a linear position of the core. Accordingly, the linear position can be detected by measuring phase difference between a reference AC signal and the output signal of the secondary coil. Likewise, velocity and acceleration change may be determined using the position change data.

A Novel Three-Phase Reference Sine-Wave Generator for PWM Inverters

Abstract: A hybrid circuit for producing a three-phase reference sine wave required with PWM inverters is described in this paper. The principle of the circuit is simple and the implementation of the circuit is easy. The circuit has all the features discussed in the literature. The unit built has, apart from the three-phase sine waves, balanced three-phase square and triangular waves. A high-frequency triangular wave already available in the circuit can be used for the PWM control circuitry. The scheme can easily be extended to generate sine waves of any number of phases.

Phase programmable signal generator means

Abstract: A phase controlled signal generator using a cyclical counter with preset and reset control terminals to provide a continually advancing digital signal. This digital signal is converted in a sine table PROM and D to A converter to a sine wave signal which signal has a phase shift with respect to a reference in accordance with a phase control preset input and which signal can be periodically synchronized to a given starting phase to maintain signal stability or Doppler frequency shift.

Capacitive transducer with continuous sinusoidal output

Abstract: A capacitive encoder utilizing a stationary plate having transmitter elements and receiver elements located on the surface thereof and a moving plate having two conductive areas separated by a sine wave shaped gap. The receiver elements on the stationary plate overlie the gap and provide outputs which vary as a function of the position of the gap with respect to the output elements. Signals from the output elements are differentially amplified and demodulated in order to provide precise sine and cosine outputs, the accuracy of which are unaffected by variations in the input signal.

Synthesized sine-wave static generator

Abstract: An inverter bridge provided with a series-network in its diagonal including an inductor and an output transformer is feedback-controlled to generate a sine wave by reference to a sine wave reference signal and in a self-oscillatory fashion of the "bang-hang" type. The series-network operates during the "hang" phase as an active filter. Transistors are used on the high frequency side of the bridge and thyristors are used on the fundamental frequency side of the bridge. Provision is made for an AC source in parallel with the load, in which case feedback control is in response to the relative shares of the sources in the common load.

Apparatus and method of phase-to-amplitude conversion in a sine function generator

Abstract: A sine wave generator uses a phase-to-amplitude converter (PAC) which functions with a novel multiplier. By using pipelined adders, intermediate amplitude and slope data from storage are combined to get an output amplitude which is equivalent to that from a prior art multiplier but without the objectionable through-put delays inherent in prior art multiplier PAC's.

Non-linear digital filter

Abstract: A filter for a pulse form of signal which substantially reduces sidebands, yet provides an output signal which is substantially free of jitter and at the same time has no inter-symbol interference. The filter comprises a circuit for detecting the pulse type of signal and for substituting .pi. radians of a sine wave signal with a positive slope upon detection of a positive going leading edge of the pulse type signal and .pi. radians of a sine wave signal with a negative slope upon detection of a negative going trailing edge of the pulse type signal, at an output terminal.

A New Current Mode Sine Wave Inverter

Abstract: A new sine wave inverter topology is presented. Its current mode operation is described, and its performance is compared to that of the more conventional series, or voltage mode, inverter. It is shown that higher frequency and more efficient operation is possible. A parity simulation of the new circuit is performed and parametric operating data are presented in a form useful for design purposes. The simulation results are verified on a 250 W 10-20 kHz hardware version of the current mode sine wave inverter.

A simple three-phase variable-fraquency oscillator

Abstract: The paper describes a hybrid, three-phase oscillator with variable frequency and voltage, and reversible phase sequence. The oscillator digitally generates three 120° phase shifted square waves, and mixes them in balanced modulators with a fixed frequency sine wave. The signals from the modulators are token through active filters resulting in constant amplitude, low distortion three-phase sine wave outputs. The magnitude of the output, voltage is controlled by varying the amplitude of the fixed frequency sine wave source. It has good frequency and phase stability.

Induction Motors for Variable Frequency Power Supplies

Abstract: Characteristics of variable frequency power supplies are compared, including sine wave, six-step square wave, and pulse width modulated (PWM) types The effects of the complex voltage waveforms and variable frequency supplies on motor efficiency, heating, torque, winding stresses, and low speed pulsating torques are described Possibilities for customizing induction motors for use with variable speed drives are considered

Large signal dynamic stability analysis of synchronised current controlled modulators. Application to sine wave high power inverters

Abstract: This paper deals with a new application of DC/DC regulators for the achievement of a sine wave output More particularly, synchronised current control modulator MC2 in a buck configuration is discribed to generate an AC waveform at 50 Hz Large signal simulation is detailed which concludes on the setting of a sawtooth corrective network to avoid the structural instability for V0 >> V/2 It is shown that small signal analysis can be applied for such application and mathematical models for discontinuous and continuous conduction modes are presented The paper ends with the test of a breadboard generating a pure sine wave without harmonic content at 85 % efficiency

Laser working device

Abstract: PURPOSE:To heat and work the work at a desired temp distribution over a wide range by providing the 1st means of oscillating a reflecting mirror to a square wave mode in which polarities are changed over alternately by having a quiescent time and the 2nd means of oscillating the same to a sine wave free oscillation mode in the quiescent time CONSTITUTION:A laser device 5 oscillates a laser beam P, and irradiates the part 3 of a quartz tube 1 via reflecting mirrors 6, 7 In this case, when a start switch 41 is operated, an electromagnet 26a is energized by a period T1, and after a period T3, a magnet 26b is energized by a period T2 and these are repeated Hence, iron pieces 25a, b are attracted alternately to electromagnets 26a, 26b, by which a reflecting mirror 7 is turned and oscillated Namely, the mirror 7 oscillates in the square wave mode in which polarities are changed over alternately by having a quiescent time and oscillates in the sine wave free oscillation mode in the quiescent period

Finite difference spectral moment estimation for profiles the effect of sample spacing and quantization error

Abstract: The mean square slope m 2 and curvature m 4 of surface profiles are characteristics that depend upon the frequency content of the roughness. Together with the mean square profile height m 0 they determine the microgeometrical behaviour of contacting rough surfaces. It is shown that in the absence of quantization error, the error due to finite sample spacing in estimating these spectral moments for a sinusoid is negligible when more than 8 points per cycle are used. In the presence of quantization error, large potential overestimates of m 2 and m 4 can occur. The error decreases initially with increased sample spacing and then increases. The severity of the distortion is shown to increase as the peak-to-peak range of the sine wave decreases relative to the full range of the a/d converter used in the digitization process.

Sonar transceiver system and method

Abstract: A sonar transceiver system and method includes an oscillator and programmable divider which are arranged to cause a transmitting transducer to transmit a plurality of four consecutive closely spaced tones in the manner of a pseudo-chirp. The receiver includes hard limiting means for converting received echo signals to binary signals and tone correlation and detection means including a shift register which compares samples of the binary received signal with a sample of a sine wave as hard limited which is carried on a storage register. A series of exclusive-OR comparator circuits effect the comparison and produce output signals of a desired magnitude when correlations are found. Switching means responsive to detection of the first of the transmitted tones causes the programming means to vary the divisors of the programmable divider to produce clock pulses of varying frequency to the shift register for the time and in the order of the transmitted tones.

Digitally-driven sine-cosine generator and modulator

Abstract: An electrical circuit and method for multiplying an analog input signal by a sinusoidal function having an instantaneous phase specified by a number signaled in binary format. As a sine wave generator, the binary number is supplied by a counter clocked at a multiple of the desired sine wave frequency. The most significant bit of the counter modulates the polarity of or actually constitutes the analog input signal which is then fed to a numerically-controlled attenuator driven by the less significant binary counter outputs. The attenuator has selectively switched resistors with values specifying a sine table of attenuation from 0 to 90 degrees. A particular resistor is selected by an analog multiplexer having paired complementary outputs so that over the range of less significant bit values, a full 180 degrees of the sinusoid is generated. As a sine wave modulator, the polarity of the analog input signal is modulated in a balanced modulator by the most significant bit of the counter, and the balanced modulator output is used as the input to the attenuator.

A new approach to transient wave generation

Abstract: An analytical model of an "episodic" wave as a function of time is given. The linear dispersion theory is applied to the transient to hindcast the wave train at a wave board which is a specified distance up-wave from a test site. First order wave board theory and linear system theory is used to convert the wave train at the wave board into a control signal. Conversion of the time discrete control signal into a smooth analog voltage signal by means of a real time digital program is described. Examples of numerical simulations and physical measurements are given.

Tone signal generating apparatus of electronic musical instruments

Abstract: Code data representing a plurality of note frequencies are stored in a first ROM and are selectively read out according to key operation of a keyboard. With the operation of a key, predetermined control data is also obtained, and this control data is cumulatively added to or subtracted from the code data as an initial value, whereby a note frequency signal corresponding to the operated key is obtained. Portions of the waveform of the resultant note frequency signal where there is a sharp change in amplitude are interpolated with a sine wave stored in a second ROM.

A carrier current transceiver IC for data transmission over the AC power lines

Abstract: A monolithic solution to the problem of sending and receiving data over power lines has been developed. The self-contained bipolar chip handles half-duplex serial data at up to 4K baud by FSK modulating a carrier frequency set at between 50 and 300 kHz. The transmitter section drives the line with a low distortion (0.1 percent) sine wave to minimize potential RFI. The 200 mW output originates from a transient-hardened on-chip transistor, and is in the form of a current that adapts to the widely varying power line impedance. The PLL receiver section has a sensitivity of 1 mV and contains a special impulse noise filter to reduce the effects of power line noise. Data of virtually any coding will pass through the system.

Displacement measuring device

Abstract: PURPOSE:To facilitate the indication of plane pole coordinates by measuring rectangular coordinate components of a two-dimensional vector quantity so as to be converted into a sine wave and a cosine wave with an amplitude proportional to the magnitude thereof and detecting the phase of a sine wave signal from the addition of the two waves. CONSTITUTION:An x component of a displacement vector quantity generated at a point 9 involved is detected with a detector 1A, the amplitude of a sine wave reference signal Vp is supplied from the power source 4 modulated into a value proportional to the magnitude of the x component and the output sine wave signal Vx is inputted into an arithmetic section 2. Likewise, an output signal corresponding to a y displacement component from a detector 1B is given to the arithmetic section 2 as a cosine wave signal Vy shifted by 90 deg. in the phase via an amplifier 12B and a phase shifter 13. The signals Vx and Vy are added at an arithmetic section 2 to be converted into a sine wave signal Vo including a phase angle theta, which is detected with a phase detector section 3A. This facilitates the indication of a plane pole coordinate in which the amplitude of Vo corresponds to the magnitude of a radius vector and the angular displacement thereof to the phase angle theta.

A Simple Modulator for Sinusoidal Frequency Shift Keying

Abstract: This paper describes a method of generating a constantenvelope sinusoidal-frequency-shift-keyed spread-spectrum signal from a sequence of phase coded rectangular pulses. In-phase and quadrature pulse streams are combined and passed through a SAW filter. The constant time delay property of the SAW filter is used to transform the rectangular pulses into the proper shape. Time and frequency domain outputs are shown for a modulator operating at 70 MHz and a chip rate of 5 Mchips/s.

Controlled emission static bar

Abstract: A controlled emission static eliminator system (wherein an A.C. high voltage is applied to the discharge electrodes of a static bar by way of a transformer) employs a biasing circuit in series with the primary of the transformer to control the amplitude and/or duration of the alternating potentials imposed on the corona discharge points. The biasing circuit includes a series-connected diode and variable resistance in one leg of a parallel network and a capacitor in the other leg. Selecting appropriate time constants for the resistance and capacitance will narrow the first half of the sine wave and broaden the second half to produce an excess of positive or negative ions, as desired, depending upon the direction of the diode. The ion emission can be controlled to yield an equal number of positive and negative ions or a predominance of ions of one polarity and can be accomplished regardless of whether the A.C. high voltage is directly connected or capacitively coupled to the points.

Pulse width modulation type inverter

Abstract: PURPOSE:To enable the control of phase stably and precisely over arbitrary fre- quency ragne by using a digital controller for a phase controller. CONSTITUTION:A digital signal is stored in an inverter output waveform data memory RAM14. Then, it is stored in the RAM14 in advance through a digital input interface 13A or the analog input interface 13B by a program for storing in the RAM12, and a PWM sinusoidal wave is directly outputted on the basis of the set frequency and voltage values to pulse amplifiers 16a, 16b, 16c with the programmable timers 15a, 15b, 15c as interfaces.

Direct current servomotor device

Abstract: PURPOSE:To enable to perform the synchronized operation of two DC motors without having a highly precise synchronization and the like by a method wherein the output signal of a driver circuit is supplied to one of the DC motors. CONSTITUTION:The DC servomotor device is consisted of a positional signal generating device 21, with which a sine wave signal nd a cosine wave signal are generated by the revolution of the first DC motor 7, a positional signal generating device 22, with which a prescribed signal is generated by the revolution of the second DC motor 15, an arithmetic operational circuit 24, with which a sine wave signal is composed and outputted in accordance with the signals sent from the positional signal generating circuits 21 and 22, and a driver circuit 25 to be used for amplification of the composite output. The first DC motor 7 is revolved in accordance with the revolution of the second DC motor 15 by supplying the output signal of the driver circuit 25 to the first DC motor.

Effect of sine wave temperature cycling on thiamin loss in fortified pasta

Abstract: The loss of thiamin in fortified pasta was studied under steady state conditions of 30°, 37° and 45°C. Using this data and the Arrhenius relationship, the reaction kinetics for each temperature were determined and then used to predict the loss of thiamin in pasta stored under a sine wave fluctuating temperature condition (25°/45°C). The predicted values were compared to actual losses found in pasta stored in the sine wave condition. Three statistical methods were utilized to specify the confidence in the predicted values. The Hicks-Schwimmer-Labuza model was found to be adequate for the prediction of the amount of loss from steady state data (20–25% error).