This paper proposes a hybrid multiband (MB) ultra wideband (UWB) system with direct sequence (DS) spreading. The theoretical error analysis for the DS-MB-UWB multiple access system with Rake receiver in the presence of multipath and narrowband interference is developed. The developed theoretical framework models the multiple access interference (MAI), multipath interference (MI) and narrowband ...

In this paper we introduce a technique of tracking and quantizing the complex envelope of a narrowband process, which is a continuous time Gauss-Markov process of arbitrary order. The narrowband process is modeled in a state space framework and several quantization schemes using the inphase and the quadrature components of the narrowband process are considered. These inphase and quadrature comp...

We propose a number of enhancement techniques to improve speech quality in bandwidth expansion (BWE) from narrowband to wideband speech, addressing three issues, which could be critical in real-world applications, namely: (1) discontinuity between narrowband spectrum and the estimated high frequency spectrum, (2) energy mismatch between testing and training utterances, and (3) expanding bandwid...

Most ultrasonic guided wave methods require tone burst excitations to achieve some degree of mode purity. In addition, it is often desirable to acquire data using multiple frequencies, particularly during method development when the best frequency for a specific application is not known. However, this process is inconvenient and time-consuming, particularly if extensive signal averaging at each...

Spread Spectrum (SS) communications offers a promising solution to an overcrowded frequency spectrum aimed growing demand for mobile and personal communication services. The proposed overlay of spread spectrum signal on existing narrowband users implies strong interference for the SS system. This paper discusses how the system performance can be improved by preprocessing to suppress narrowband ...

We present tunable waveguide-based optical parametric amplification by four-wave mixing (FWM) in silicon nitride waveguides, with the potential to be set up as an all-integrated device, for narrowband coherent anti-Stokes Raman scattering (CARS) imaging. Signal and idler pulses are generated via FWM only 3 nJ pump pulse energy stimulated using 4 mW of a continuous-wave seed source, resulting 35...

We develop a linearized imaging theory that combines the spatial, temporal and spectral aspects of scattered waves. We consider the case of fixed sensors and a general distribution of objects, each undergoing linear motion; thus the theory deals with imaging distributions in phase space. We derive a model for the data that is appropriate for any waveform, and show how it specializes to familiar...

Passive sonar sensors are the main source of information for a submerged submarine. Modern sonar systems like ISUS 90 offer a number of acoustic antennas and combined signal processing for broadband and narrowband detection and analysis of target noise. While broadband detection is often used to obtain an overview of the targets surrounding the own ship, narrowband processing enables the detect...

For high data rate ultra wideband communication system, performance study of mutual interference such as suppression of interference signal by performing pulse shaping from UWB to other narrowband system using wavelet technique and reduction of interference from other narrowband system to UWB system in conjunction with Transmitted-Reference (TR-UWB) signaling scheme with adaptive receivers is a...

It is a great challenge to obtain narrowband and photomultiplication (PM) type organic photodetectors (OPDs) without optical filters due to the broad absorption range and large exciton binding energy of organic materials. Narrowband OPDs with the special structure of ITO/PFN-OX/P3HT : PC61BM (100 : 1,wt/wt)/Al were successfully fabricated with different active layer thicknesses, exhibiting a tu...