We theoretically investigate the use of Rayleigh surface acoustic waves (SAWs) for refractive index modulation in optical waveguides consisting of amophous dielectrics. Considering low-loss Si3N4 waveguides with a standard core cross section of 4.4×0.03 μm size, buried 8-μm deep in a SiO2 cladding we compare surface acoustic wave generation in various different geometries via a piezo-active, le...

As a potential member of next generation wireless communications, the reconfigurable intelligent surface (RIS) can control reflected elements to adjust phase transmitted signal with less energy consumption. A novel RIS-assisted index modulation scheme is proposed in this paper, which named generalized (GRPM). In GRPM, bits are mapped into combination conveyed through on RIS, and detected by max...

Model modulation index Figure 1 (a) An input image is convolved with a model V1 front-end with units tuned to different orientations and spatial frequencies. The first V2 stage computes derivatives over the activation map of V1 across space, as well as orientation and spatial frequency. We modelled “V2 simple cells” as the rectified output of these filters. The final V2 stage pools and rectifie...

Radio-over fiber technology (RoF) fulfills the demand of future wireless services. In this paper, simulative analysis of radio-over fiber system employing external modulation using MachZehnder modulator is carried out by considering the effect of fiber dispersion. Analytical and simulative analysis shows the periodic behaviour of system with respect to modulation index and length of the optical...

We introduce "the modulation cepstrum," a novel representation of an acoustic signal used to distinguish speech signal and environmental noises. The modulation cepstrum was computed by taking the inverse Fourier transform of the logarithmic modulation spectrum, a spectral representation of the temporal dynamics of a sub-band. We calculated the center of gravity of accumulated the modulation cep...

In this letter, a novel supplementary index bit aided transmit diversity (SIB-TD) approach is proposed for an enhanced discrete cosine transform based orthogonal frequency division multiplexing with modulation (EDCT-OFDM-IM) system. Specifically, conventional (IM) employed the first antenna, i.e., main branch, and non-activated subcarriers’ indices in one group are utilized IM mapping on same s...

Amplitude modulation (AM) and frequency modulation (FM) in speech signals are believed to reflect various non-linear phenomena during the speech production process. In this paper, the amplitude and frequency modulation patterns are analyzed for the first three speech resonances in relation to the fundamental frequency (F0). The formant tracks are estimated, and the resonant signals are extracte...