Bandwidth (signal processing)

About: Bandwidth (signal processing) is a research topic. Over the lifetime, 48550 publications have been published within this topic receiving 600741 citations. The topic is also known as: Bandwidth (signal processing) & bandwidth.

5G Field Trials: OFDM-Based Waveforms and Mixed Numerologies

Abstract: Service diversity is expected in the upcoming fifth-generation (5G) cellular networks, which poses great challenges to the underlying waveforms to accommodate heterogeneous service requirements in a flexible way. By dividing the bandwidth into several subbands, each having a different numerology, this paper reports a field trial in time division duplex downlink conducted on a configurable test bed in a real-world environment for the performance evaluations of orthogonal frequency-division multiplexing (OFDM)-based 5G waveform candidates, i.e., cyclically prefixed OFDM (CP-OFDM), windowing OFDM (W-OFDM), and filtered OFDM (f-OFDM), in the presence of mixed numerologies. Field trial results confirm the feasibility of mixed numerologies and reveal the impact of several important system parameters, e.g., guard bandwidth, data bandwidth, signal-to-noise ratio (SNR), and transmit power. The results also suggest that f-OFDM outperforms CP-OFDM and W-OFDM in terms of both the spectrum efficiency and robustness in a high SNR regime, and the gain increases with a higher inter-numerology out-of-band interference. In some specific scenarios, ideal spectrum utilization can be realized by f-OFDM which completely removes the guard band.

Derivative analysis of hyperspectral data

Abstract: With the goal of applying derivative spectral analysis to analyze high resolution, spectrally continuous remote sensing data, several smoothing and derivative computation algorithms have been reviewed and modified to develop a set of cross-platform spectral analysis tools. Emphasis was placed on exploring different smoothing and derivative algorithms to extract subtle spectral features from any continuous spectral data sets. With interactive selection of bandwidth and sampling interval (band separation), the algorithm can optimize noise reduction and better match the scale of spectral features of interest. Laboratory spectral data were used to test the performance of the implemented derivative analysis modules. An algorithm for detecting the absorption band positions was executed on synthetic spectra and a soybean fluorescence spectrum to demonstrate the usage of the implemented modules in extracting spectral features. Upon examination of the developed modules, issues related to the smoothing and the spectral deviation caused by the smoothing or derivative computation algorithms were also observed and discussed. The scaling effect resulting from the migration of band separations when using the finite approximation derivative algorithm was thoroughly inspected to understand the relationship between the scaling effect and noise removal.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Method and apparatus for the transmission and reception of a multicarrier digital television signal

Abstract: A method and apparatus for encoding a television source signal having a first bandwidth, into a frequency multiplexed signal having a narrower bandwidth and comprising a plurality of subcarriers modulated with digital information. Each of said subcarriers has an amplitude, bandwidth and coding characteristic which reflects the relative importance of the digital information provided thereby. The frequency multiplexed signal is suitable for use in a broadcasting environment wherein a conventional television signal is also used and wherein said subcarriers are disposed in frequency, in positions which are least likely to result in interference to or from said conventional signal. The invention also includes a receiver for decoding the frequency multiplexed signal and for providing a high definition display.

Wideband 3D Frequency Selective Rasorber

Abstract: This communication presents a 3D frequency selective rasorber (FSR) with bandpass filtering response and wideband absorption characteristics. By loading an array of lumped resistors at one side of a microstrip-line based bandpass frequency selective structure (FSS), multiple resonators, including lossy resonators, are constructed. The bandpass performance with high selectivity is provided by resonators in the substrate region of the microstrip line. The absorption characteristic is obtained by the lossy resonators at the resistor-loaded side of the air region. All reflected waves at the resistor-loaded side can be effectively absorbed by appropriately choosing the resistance value. Physical mechanism of the FSR is analyzed with the aid of an equivalent circuit model and current distributions. As an example, a prototype of the designed FSR is fabricated and tested. Experimental results show that the insertion loss at the center frequency is 2.4 dB and a bandwidth of 114% for the absorption better than 10 dB in the upper rejection band is achieved under the normal incidence.

Digital beamforming in ultrasound

Abstract: The effects on array gain and sidelobe level of a practical digital beamforming (DBF) processor under the wideband conditions typical of ultrasound is discussed. It is concluded that a relatively simple design that replaces each analog delay line with a tapped, digital shift register (DSR) and a digital phase shift operation adjusted for midband will provide the desired performance, provided that the sampling rate of the signal at the input to the DSR is 4 to 10 times the bandwidth. More realistically, when nonidealized passbands are taken into account and the typical condition whereby the transducer frequency is about twice the bandwidth is considered, the rule of thumb for the sampling rate is that it must be 4 to 10 times the transducer frequency. >