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Signal generator

About: Signal generator is a research topic. Over the lifetime, 17786 publications have been published within this topic receiving 115768 citations.


Papers
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Journal ArticleDOI
TL;DR: It is shown, and confirmed by simulation, that to maintain signal-to-interference ratios of 20 dB or greater for the OFDM carriers, offset is limited to 4% or less of the intercarrier spacing.
Abstract: This paper discusses the effects of frequency offset on the performance of orthogonal frequency division multiplexing (OFDM) digital communications. The main problem with frequency offset is that it introduces interference among the multiplicity of carriers in the OFDM signal. It is shown, and confirmed by simulation, that to maintain signal-to-interference ratios of 20 dB or greater for the OFDM carriers, offset is limited to 4% or less of the intercarrier spacing. Next, the paper describes a technique to estimate frequency offset using a repeated data symbol. A maximum likelihood estimation (MLE) algorithm is derived and its performance computed and compared with simulation results. Since the intercarrier interference energy and signal energy both contribute coherently to the estimate, the algorithm generates extremely accurate estimates even when the offset is far too great to demodulate the data values. Also, the estimation error depends only on total symbol energy so it is insensitive to channel spreading and frequency selective fading. A strategy is described for initial acquisition in the event of uncertainty in the initial offset that exceeds 1/2 the carrier spacing, the limit of the MLE algorithm. >

2,475 citations

Proceedings ArticleDOI
C.W. Farrow1
07 Jun 1988
TL;DR: An FIR (finite-impulse-response) filter which synthesizes a controllable delay which has the ability to interpolate between samples in the data stream of a band-limited signal is described.
Abstract: The author describes an FIR (finite-impulse-response) filter which synthesizes a controllable delay. By changing the delay the filter has the ability to interpolate between samples in the data stream of a band-limited signal. Because high sampling rates are not required, the filter is especially suited for implementation in a digital signal processor (DSP), and has been implemented in a real-time DSP. The interpolator can be used as a practical way to reconstruct an original band limited signal from samples taken at the Nyquist rate. The variable delay filter can also be used as a more general computational element. Performance results are presented. >

853 citations

Patent
22 Mar 2001
TL;DR: In this paper, the authors present methods and systems for signal processing for illumination control signals, which may include a decoder for decoding a combined signal and a connection for delivering a portion of the combined signal to an illumination source, which source is capable of generating an illumination condition from the portion of combined signal.
Abstract: Provided herein are methods and systems for signal processing for illumination control signals, which may include a decoder for decoding a combined signal and a connection for delivering a portion of the combined signal to an illumination source, which source is capable of generating an illumination condition from the portion of the combined signal. The system may also include an encoder for encoding the combined signal from and illumination control signal and a second signal. The combined signal may include any signal, such as a video signal, a radio frequency signal, an electrical signal, an infrared signal, an acoustic signal, and audio signal, and an optical signal. The encoder may send signals to the decoder by any known method or system, such as broadcast, cable, network, circuit, or the like. The system may include a controlled illumination source and another device, which may be any electrical device, such as an entertainment device. The device may be a television, a computer, a compact disc player, a stereo, a radio, a video cassette player, a DVD player, a toy, a CD-ROM drive, a film projector, a surround sound system, a dolby sound system, a THX sound system, and a tape player. The decoder may be connected to the controlled devices by any connection, such as a circuit, a network, a data bus, a cable, a wire, a radio frequency transmitter and receiver, an infrared transmitter and receiver, a broadcast transmitter and receiver, an optical transmitter and receiver, an acoustic transmitter and receiver, a microwave transmitter and receiver, and a circuit. The system may also include a signal generator for generating signal that controls the other device and an illumination control driver for generating the illumination control signal for the illumination source. The illumination source may be an LED system that is controlled by a microprocessor to vary at least one of the color and intensity of the illumination produced by the illumination source in response to the illumination control signal.

746 citations

Patent
03 Jun 1996
TL;DR: In this paper, an electrosurgical generator with an improved microprocessor was proposed to generate output waveforms in the form of a serial digital output from the microprocessor, which is then transformed into an output RF output in an amplifier stage.
Abstract: An electrosurgical generator (10) has an improved design for generating output waveforms using a microprocessor (15). The waveforms are generated in the form of a serial digital output from the microprocessor (15). The serial digital output is transformed into an electrosurgical RF output in an amplifier stage. The improved design also includes a monitoring circuit to continuously monitor the serial digital output by time-averaging the output, and then comparing that value with a threshold. The electrosurgical generator (10) comprises a microprocessor (15), an algorithm in the microprocessor (15) capable of toggling an output port of the microprocessor (15), an output amplifier (16), an adjustable high voltage DC power supply (17), a patient circuit including an active electrode (12) and a return electrode (13). The electrosurgical generator (10) may further comprise a mode selector (20) for selecting one of a plurality of pulse patterns in the serial digital output, and a plurality of command sequences in the algorithm, where each command sequence is designed to produce one of the plurality of patterns. There may also be a tank damp circuit (22) for reducing the amplitude of voltage spikes in the electrosurgical output, and a pulse suppression circuit. The monitoring circuit comprises a low pass filter (19) and a comparator to verify operation of the waveform generator.

742 citations

Journal ArticleDOI
TL;DR: A digital algorithm is proposed that can be implemented very efficiently even at high data rates and allows free-running sampling oscillators and a novel planar filtering method that prevents synchronization hangups.
Abstract: The digital realization of timing recovery circuits for digital data transmission is considered. A digital algorithm is proposed that can be implemented very efficiently even at high data rates. The resulting timing jitter has been computed and verified by simulations. In contrast to other known algorithms, the one presented here allows free-running sampling oscillators and a novel planar filtering method that prevents synchronization hangups. >

604 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202324
202279
2021133
2020394
2019483
2018588