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.

Narrow-band optical channel-dropping filter

Abstract: Waveguide couplers are combined with lambda /4 shifted distributed feedback (DFB) resonators to produce narrowband channel dropping filters. The bandwidth of the filter can be made much narrower than the stopband of the grating. It is possible to remove the spurious responses of the grating filter by appropriate dispersion characteristics for the coupled waveguides. However, in some practical applications it may not be necessary to do this, if all channels can be accommodated within half the grating bandwidth of the filters. >

A novel highly efficient broadband continuous class-F RFPA delivering 74% average efficiency for an octave bandwidth

Abstract: A novel, highly efficient and broadband RF power amplifier (PA) operating in “continuous class-F” mode has been realized for first time. The introduction and experimental verification of this new PA mode demonstrates that it is possible to maintain expected output performance, both in terms of efficiency and power, over a very wide bandwidth. Using recently established continuous class-F theory, an output matching network was designed to terminate the first three harmonic impedances. This resulted in a PA delivering an average drain efficiency of 74% and average output power of 10.5W for an octave bandwidth between 0.55GHz and 1.1GHz. A commercially available 10W GaN HEMT transistor has been used for the PA design and realization.

Communication techniques using monopulse waveforms

Abstract: This paper studies wireless communication systems using technology that does not require a carrier signal. The vehicle used for transmission is a monopulse waveform. Such waveforms possess a bandpass nature, having no DC content. The short time duration of these waveforms, typically nanoseconds, provides has an ultrawide bandpass characteristic, with a spectrum in the range of hundreds of megahertz, making them ideally suited for a spread spectrum communication system. The temporal representations of several monopulse signals are illustrated, and the power spectral densities of the Gaussian and Rayleigh monopulse waveshapes are presented. The relationship between effective time duration, peak-to-RMS value, and bandwidth is detailed. The spectral effect of pulse amplitude modulated data and pulse position modulated data is compared. A methodology for efficient data transmission and a technique for rate doubling at no cost in bandwidth is described. Diversity methods to mitigate a harsh environment, such as those encountered in fading channels, jamming, and multipath situations, are introduced.

Method and device for image and video transmission over low-bandwidth and high-latency transmission channels

Abstract: The present invention provides a method for transmission of a images and/or video over bandwidth limited transmission channels having varying available bandwidth, which method comprises the use of a classification algorithm for • decomposing the images and/or video to be transmitted into multiple spatial areas, each area having a specific image type; • detecting the image type of each of those areas • separately selecting for each of those areas an image and/or video encoding algorithm having a compression ratio. The classification algorithm prioritizes each of the areas, the classification algorithm increasing the compression ratio of the image and/or video encoding algorithm dedicated to spatial areas having lower priority in case of decreasing bandwidth.

Bandwidth and wavelength-tunable optical bandpass filter based on silicon microring-MZI structure.

Abstract: A novel and simple bandwidth and wavelength-tunable optical bandpass filter based on silicon microrings in a Mach-Zehnder interferometer (MZI) structure is proposed and demonstrated. In this filter design, the drop transmissions of two microring resonators are combined to provide the desired tunability. A detailed analysis and the design of the device are presented. The shape factor and extinction ratio of the filter are optimized by thermally controlling the phase difference between the two arms of the MZI. Simultaneous bandwidth and wavelength tunability with in-band ripple control is demonstrated by thermally tuning the resonance offset between the two microring resonators.