Sine wave

About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.

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.

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.

Using the fast Fourier transform to determine the period of a physical oscillator with precision

Abstract: Measuring the period of torsion pendulums with precision has long been a formidable challenge in gravitation experiments, particularly those measuring the Newtonian gravitational constant G. An alternative method to fitting the position signal of the pendulum to a sine wave is the use of the power spectrum generated by the fast Fourier transform (FFT) as the source of information from which the period of oscillation can be determined. There are, however, known limitations to the use of a FFT to measure the period of a physical oscillator with precision. These limitations include two effects due to the finiteness of the duration of the sinusoidal data record and one effect due to the uncertainty of the starting phase of the oscillator relative to the window imposed by this duration. We have done a phenomenological study of the FFT using a desktop computer to imitate a precision oscillator having the physical characteristics of a finite damping constant and drift in the zero potential‐energy position. Also,...

The Design and Construction of a Stark‐Modulation Microwave Spectrograph

Abstract: A detailed description of a Stark‐modulation (see reference 1) microwave spectrograph which has been designed and constructed in this laboratory is given. Circuit diagrams and values of the components are given for all the custom‐built equipment. The frequency range is from 17 to 28 kmc/s. Peak Stark‐modulation voltages up to 1500 volts sine wave and 800 volts square wave are used. The sensitivity is better than 1×10−8 cm−1. The absorption lines are about 300 kc wide at half‐power and the practical limit of resolution is between ½ and 1 mc. Frequencies may be measured to better than ±0.08 mc.

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.