Showing papers on "Sine wave published in 1977"

A solution to the problem of spontaneous line splitting in maximum entropy power spectrum analysis

Abstract: Under certain conditions, Burg maximum entropy spectra of sampled sine waves, in the presence of additive Gaussian white noise, show either spontaneous line splitting (at low noise levels) or appreciable frequency shifting (at moderate noise levels). This difficulty arises because an unnecessary constraint is imposed during the minimization of the prediction error power. When the constraint is relaxed and a lighter one imposed, the error power decreases and the problem is solved. The nature of the constraint is discussed, and the mathematical details of the new method are presented. The new method is verified by using a few simple test cases in which spontaneous line splitting is healed or frequency shifting is reduced drastically (Fougere, 1975).

Reception of medium vibration by thoracal hairs of caterpillars of Barathra brassicae L. (Lepidoptera, Noctuidae)

Abstract: 1. A single sensory cell innervates each of the 8 filiform hairs on the thorax ofBarathra brassicae caterpillars. 2. It is not spontaneously active nor does it respond to a maintained deflection of the cuticular hair. It responds to changes in hair position away from or back to resting position in a purely phasic fashion (Fig. 1). 3. At a constant duration of hair motion for reaching the final deflection the number of occurring impulses (y) depends on hair-deviation-angle (x) according to the power functiony=6.76·x°0.38. 4. The impulse rate (y) drops with time (t) after onset of step stimuli according toy = 1174.9·t−0.67 (Fig. 3). 5. If one plots the first interpulse interval against angular velocity of hair motion a sigmoid shaped response curve results with its steepest slope in the range 50-100°/s (Fig. 6). 6. The directional characteristic of the sensory cell shows a cadioid-like profile of sensitivity (Fig. 15) with its sensitivity maximum for deflections in the direction where the dendrite inserts at the hair base. 7. The threshold of impulse initiation by sine stimulation drops from 2.5° hair deflection from resting position at 40 Hz to 0.5° deflection at 150 Hz and than stays at a nearly constant level up to 1000 Hz. The response breaks abruptly off around 1000 Hz (Fig. 9). Bristles on the thoracic segments show a minimum threshold curve with a sensitivity maximum of 0.3° at 150 Hz (Fig. 10). 8. At sine stimulation the sensory cell of the filiform hairs adapts only slowly. At a stimulus frequency of 100 Hz the response begins to decrease after 5 s and vanishes after ca. 20 s. 9. The impulses occur at a constant phase of the sine wave at a given stimulus frequency. At frequenciesf< 40 Hz every half sine wave is responded to, at frequenciesf≳= 40 Hz the response occurs only at hair motion to the ventral side. In the frequency range 40 Hz ≦f≦ 200 Hz every sine wave is responded to by one impulse. 10. Response to sine wave onset with different rise-time has an initial phasic or “quasi-phasic” peak of discharge rate (Fig. 13). 11. The medium vibration in the near-field of a flying wasp is an adequate stimulus for the filiform hair. A flying wasp can stimulate the sensory cell from a distance of maximally 70 cm.

Sine wave beam web and method of manufacture

Abstract: The invention disclosed is (1) a sine wave web for structural elements made of composite materials, (2) structural combinations incorporating the web, and (3) a method of manufacturing the web. The concept disclosed avoids bunching and distortion of the fibers of the composite web material as it is shaped and flanged for attachment to adjacent structure, such as the chords and capstrips of an I-beam.

Direct digital frequency synthesizer

Abstract: A desired output frequency can be generated by applying a corresponding digital phase step number to an accumulator to generate multiples of the number for application to a sine wave look-up table from which digital samples of the sine wave amplitude are obtained. The digital samples can be applied through a digital-to-analog converter to produce the desired output frequency in analog form. A time division multiplex system is disclosed in which a plurality of digital phase step numbers are used to generate an equal plurality of output frequencies. Each digital phase shift number may be altered in accordance with modulating signals so that each output frequency is frequency-shift keyed, and/or phase shift keyed, and/or on-off keyed.

Charge coupled device filters and modems incorporating such filters

Abstract: A Modem utilizing process technology compatible CCD and IGFET circuits and sub-systems incorporated on a single I.C. chip. CCD transversal filters are employed as bandpass filters, being tuned for different modes of operation by adjustment of the clock frequency. The bandpass filters are operated in conjunction with a charge amplifier to remove d.c. offset from the analog output of the filters. The demodulator section of the Modem also incorporates low-pass filter employing switched resistors. The modulator section includes waveform generators based on a digital-to-analog converter including switched capacitors having values selected such that a sine wave having minimal distortion is generated when switched in proper sequence. Provision is made for digital inputs to control the frequency and amplitude of the sine wave output. The Modem can be operated under control of a microprocessor.

A Versatile Three Phase Oscillator

Abstract: This paper presents the design and performance of a versatile three phase oscillator The oscillator is built using digital circuits It provides five distinct output waveforms: sine, triangle, square, trapezoidal and symmetrically clipped sine waves Independent signals control output frequency, amplitude and phase sequence The oscillator has been built and successfully used in a cycloconverter powering a linear synchronous motor

Circuitry for driving a non-linear transducer for ultrasonic cleaning

Abstract: A circuit is disclosed for providing an 80 kilohertz sine wave to an ultrasonic transducer which includes an 80 kilohertz square wave generator driving a transistor having the primary of a transformer in its collector circuit. The secondary of the transformer drives a power transistor which has the transducer drive circuitry in its collector circuit. The transducer drive circuitry includes a transformer whose primary is connected in series with an inductor. The secondary of the transformer drives the transducer and has a capacitor connected thereacross. A third winding of the transformer is connected to have its output rectified to serve as a power supply for the square wave generator.

Amorphous threshold switch response to pulse burst waveforms

Abstract: The switching response of thin‐film amorphous chalcogenide threshold switches to pulse bursts of sine waves and square waves is reported. For the waveforms and devices investigated, preswitching behavior as evidenced by the delay time is a function of the rms voltage applied to the device. Switching voltages were slightly greater than the minimum required for switching.

Power factor corrector for a resistive load

Abstract: An apparatus for substantially eliminating the effects of a nonsinusoidal current from a reactive or nonlinear load as applied to a resistive load requiring an input current that appears to be sinusoidal. If the amplitude of the current source as applied to the resistive load can be controlled through a switching regulator by matching a sine wave reference signal with current inputed from the current source then said input current may be forced into a sinusoidal mode that is in phase with the voltage thereof. Accordingly, with the input current in a phased sinusoidal condition, harmonic elimination and power factor correction may be afforded to the inputed power relative to the resistive load.

Test particle study of nonlinear wave‐particle interaction in the magnetosonic mode: Pure sinusoidal wave model

Abstract: A numerical study of the motions of test particles in a sinusoidal magnetosonic (hydromagnetic fast) wave is presented. The magnetic amplitude of the wave was varied from 1% to 40% of the external magnetic field strength. The motions of 400 particles are calculated in each computer run by time integration of the equation of motion, without the use of the guiding center approximation. The particles are initially distributed uniformly in space with a specified velocity distribution; the space and velocity distributions then evolve in time. For small wave amplitudes, the numerical results agree well with the small amplitude kinetic theory of collisionless Landau damping of hydromagnetic waves. In large amplitude cases, nonlinear effects such as particle trapping, saturation and oscillation characteristics of the average kinetic energy, and the diffusion of particles in velocity space are observed. The physical interpretation of these numerical results is discussed in terms of the guiding center approximation.

Apparatus for monitoring electrical properties of a liquid

Abstract: Apparatus for monitoring the temperature, and the electrical conductance and capacitance, of a liquid product during processing of the liquid product, and automatically converting the measured electrical conductance and capacitance values to the conductance capacitance of the liquid product at a selected reference temperature of the product. An a.c. sine wave voltage is applied across a conductivity cell immersed in the liquid and an admittance signal proportional to the current flowing through the cell is resolved into a signal proportional to the conductance of the liquid, and a signal proportional to the capacitance of the liquid, within the cell. A thermocouple at the conductivity cell produces a signal proportional to the liquid temperature, which is compared with a selected reference temperature signal, and the signal proportional to the difference between the temperature signal and the reference signal is applied to temperature compensation circuits to produce respective signals proportional to the conductance and capacitance of the liquid at the selected reference temperature.

Digitally synthesized multi-frequency signal generator

Abstract: A solid state signal generator for producing frequency combinations such as used in multi-tone telephone systems. The output of a crystal oscillator is divided to obtain binary signals proportional to the selected pairs of the seven multi-tone frequencies. These signals are scaled with selected binary output signals generated by a free-running pattern generator and representing slopes at various points on a sine wave to produce a binary signal stream that is applied to a controlled charge digital-to-analog conversion circuit that partially charges or discharges a capacitor in accordance with the binary 1's and 0's to produce an output waveform across the capacitor that corresponds to the combined pair of selected individual tone frequency sinusoids.

Signal compander system

Abstract: An improved signal conditioning compander system includes one or more weighting networks designed so that the system provides a substantially flat single-frequency sine wave sweep response through or on the transmission medium throughout the frequency bandwidth of interest. The system provides greater high-frequency weighting than heretofore practical and at the same time permits full level transmission over the entire frequency spectrum transmitted or recorded.

System for the generation of sine oscillations

Abstract: A system for the direct synthesis of sine oscillations by means of a sine table which has a digital counter as its input. The output of the counter is also coupled to a logarithm device and from there to a digital analog converter. The converter is coupled to a controlled pulse generator which feeds the counter with a frequency which varies logarithmically with time.

Some observations on single-element control sine-wave oscillators

Abstract: A new generalized approach to the study of the variable frequency sine-wave oscillators in active RC filters having a single-element control facility is presented. The constraints on the filter functions which are amenable for generation of such oscillations with feedback are derived and a number of exemplary circuits are given and also their frequency and gain limits in tables. The oscillation stability is also studied following Loeb's criterion of limit cycle stability for systems having saturation characteristics in the active parts. The circuits are also shown to yield VCO's with voltage controlled FET as the frequency controlling parameter, The possible configurations of the amplifier circuits with operational amplifiers as the building block are considered including a discussion on bandwidth limitation.

Digital drive and phase-lock for seismic vibrators

Abstract: This invention concerns a synchronizing control for an electro-hydraulic seismic vibrator, which control utilizes a magnetic tape cassette reader that puts out a train of pulses of changing time spacing of a preselected pattern. This operates a counter which controls the address of a read-only memory which has a selected number of memory locations, each one holding a corresponding one of a sequence of digitized values forming a single cycle of a sine wave. By continuing to operate the counter, each of the values stored in the memory is sequentially placed in an output circuit to provide a digitized sinusoidal reference sweep signal. The cassette reader signal also drives a second counter through a frequency ratio control of the pulses provided by the cassette. By this means, the second counter can be varied to count at a different rate from the first counter. The second counter also addresses the read-only memory, and the outputted digital signals are converted to an analog signal which is used as the drive sweep for the vibrator. The motion of the vibrator baseplate is detected by an accelerometer, the signal of which is doubly integrated and converted to digital form. One of two identical digital filters filters the reference sweep signal and the other the accelerometer signal. The filter outputs then go to a phase comparison network which controls the frequency ratio control of the second counter. When the reference sweep leads or lags the output signal from the accelerometer, the frequency ratio control advances the second counter at a higher or a lower rate, as necessary, to convert the second digital output of the memory to a correspondingly different phase, in order to correct the phase relation of the vibrator output and the reference sweep.

Circuit arrangement for generating a pulse-width modulated signal

Abstract: A digital device for controlling a three-phase motor comprises a circuit arrangement for generating three pulse-width modulated carrier waves which are 120° phase-shifted relative to each other, whose modulation depth as a function of time represents a sinewave. A first clock signal periodically starts an up/down counter which counts the second clock signal. The carrier wave is generated by switching a flip-flop each time that the maximum count of the up/down counter is reached and the various modulation pulses which are required are generated symmetrically relative to this maximum count. A sequential network modulates the carrier wave sequentially with the correct modulation pulses.

Generating circuit for double frequency signal

Abstract: PURPOSE:To realize the circuit requiring no phase shifter and enabling to produce the double frequency (2f) rectangular wave signal of 50% duty cycle requiring no adjustment, by providing a circuit generating a rectangular signal and a triangle wave (or a sinusoidal wave) in synchronizing with it.

Audio-to-video converter-modulator

Abstract: An audio signal to color pattern display signal converter-modulator includes an input audio signal section, four frequency band filters, horizontal sync and sweep circuitry, vertical sync and sweep circuitry, a pulse width modulator section, a level converter-modulator matrix, a chroma encoder circuit section and a chroma and luminance modulator and video output circuit section. The pulse width modulator section includes a CMOS NAND gate associated with each of the four frequency band filters, each NAND gate and each filter combination corresponding to a different primary display color. Each NAND gate has one input coupled to an output voltage signal from its corresponding filter section and the other NAND gate input is coupled to a sine wave signal. There are four such sine wave signals each sequentially phase shifted by 90° from the preceding adjacent sine wave. The resulting pattern, which is displayed on a television receiver, is a vertical stack of four elliptical areas (when all four NAND gates are turned on) each area being of a different color. As the particular audio signal within each frequency band increases and decreases in amplitude, the corresponding elliptical area increases and decreases about a center point causing adjacent elliptical areas to overlap thereby creating color blending.

Voltage regulation apparatus using simulated ferroresonance

Abstract: An amplitude-regulated, distortion-free sine wave voltage source capable of operating from input sine waves, square waves or quasi-square waves, this ferroresonance-simulating inverter apparatus includes a special control winding and shorting switch therefor that is cyclically operated by a control circuit. By varying the point of time during each half cycle at which the control winding becomes short circuited in accordance with cyclic comparisons being made between recurring voltage ramps and an error signal related to system output voltage level, a feedback loop is provided to regulate such output voltage. The transformer secondary is not required to operate in the saturated mode through use of a ferroresonant capacitor in the usual manner, but the effect of ferroresonance is simulated to achieve regulation through the shunting of flux to saturate separate core shunts in a small fraction of the total core. Further reductions of harmonic distortion are attained by incorporating harmonic wave traps in the output permitted by utilizing secondary reactance resonant tuning to the harmonic now made possible by obviating the need for ferroresonance at the fundamental frequency.

Demodulation circuits of FM stereophonic receivers

Abstract: A demodulation circuit for an FM stereo receiver is constructed to invert the FM stereo composite signal by an inverting amplifier and then to supply the inverted signal to a switching circuit for producing demodulated left and right signals. The composite signal is applied to a phase-locked loop circuit for applying a 38 kHz switching signal to the switching circuit. A 19 kHz signal produced by the phase-locked loop circuit is converted into a sine wave signal by a waveform converting circuit. The sine wave signal is converted into a direct current signal which is applied to one input of a level comparator having the other input connected to receive the 19 kHz pilot signal extracted from the composite signal. The output of the comparator is sent to a level control circuit which controls the level of the signal supplied to the input of the inverting amplifier. Accordingly, the pilot signal is canceled in the signal sent to the switching circuit. The left and right output terminals of the switching circuit are connected to the input of the inverting amplifier through negative feedback circuits.

Drum or disc brake for vehicle - has matching corrugated friction faces of sine wave form to increase braking area

Abstract: The friction face of a vehicle brake is corrugated in order to increase the contact area between the stationary and the rotating brake members (1, 9, 11). The corrugation has the shape of a sine wave whose positive and negative loop (17, 19) is part of a circular form. The included angle of the sine wave in the direction of the applied brake force is less than 90 deg. The brake has increased efficienty, reduced wear and improved heat dissipation. the sine wave form of the friction area can be applied to a disc brake as well as a drum brake.

System for identifying and correcting the polarity of a data signal

Abstract: A very low power asymmetrical polarity marking signal which may be the sum of a cosine wave and its coherent second harmonic is added to a symmetrical message signal before transmission. At the receive the polarity information may be recovered from the average dc value of the positive and negative peaks of the polarity signal or from the coincidence of peaks of the fundamental and second harmonic components.

Multi-frequency generator using digital technique

Abstract: A circuit for producing sinusoidal wave-forms representative of signals used in voiceband signaling for telephone dialing, frequently referred to as DTMF signaling. A sine wave is broken into a predetermined number of time increments. The amplitude changes for each increment may be indicated in the form of a binary digital word for a quadrant of the curve. The remaining quadrants will exhibit essentially the same change characteristics at like time increments with only the bit order reversed or the polarity changed thus, the basic binary word is unchanged for each quadrant. A programmable memory is set to produce the binary word at a selected clock rate. In this way, synthesis of a plurality of sine waves may be readily produced using delta modulation techniques. For all sine curves, the number of time increments remains the same, the rate of pulsing the increments is varied responsive to the keyboard signals generated. For telephone use, a high and a low signal are synthesized at essentially the same time. These signals may further be combined on a single output for transmission to the tone receiver.

Is the Graph of Temperature Variation a Sine Curve? An Application for Trigonometry Classes.

Abstract: data and ends with a trigonometric func tion that models the physical situation. There are many familiar phenomena that are periodic, such as sound waves, electrical currents, business cycles, and air pollution levels. For our project we chose the local yearly temperature pattern because the data were readily available and because Alaskans are generally concerned with the weather. Having introduced a general sine curve to represent

A digital noise and sine-wave generator

Abstract: A circuit is described that will digitally generate three kinds of signal useful in auditory research: broad-band pseudorandom noise, low-pass-filtered Gaussian noise, and low-distortion sine waves. This digital circuit has two advantages over its analog counterparts, ease of calibration and adaptation to computer control.