Orthogonal frequency division multiplexing (OFDM) has become a promising method for many wireless communication applications. However, one main drawback of OFDM systems is the high peak-to-average power ratio (PAPR). Selected mapping (SLM) is a well-known technique to decrease the problem of high PAPR in OFDM systems. In this method, transmitter is obliged to send some bits named side informati...

Abstract The spectral characteristics viz. reflectivity, bandwidth, and sidelobes’ intensity for uniform apodized (Gaussian, hyperbolic tangent, apod1, sine, raised sine) fiber Bragg gratings (FBGs) were studied as a function of grating length index modulation. optimal modulation to obtain maximum reflectivity minimum sidelobes determined, needed sensing applications. impact various apodization...

Sharp and highly-selective tunable optical band-pass filters, based on stimulated Brillouin scattering (SBS) amplification in standard fibers, are described and demonstrated. Polarization pulling of the SBS-amplified signal wave is used to increase the selectivity of the filters to 30 dB. Pump broadening via synthesized direct modulation was used to provide a tunable, sharp and uniform amplific...

We have developed a wideband digital frequency detector for high-speed frequency modulation atomic force microscopy (FM-AFM). We used a subtraction-based phase comparator (PC) in a phase-locked loop circuit instead of a commonly used multiplication-based PC, which has enhanced the detection bandwidth to 100 kHz. The quantitative analysis of the noise performance revealed that the internal noise...

The Enhanced Variable Rate Codec (EVRC) is a standard for the “Speech Service Option 3 for Wideband Spread Spectrum Digital System,” which has been employed in both IS-95 cellular systems and ANSI J-STC-008 PCS (Personal Communications Systems). This paper investigates the combination of turbo codes with Unequal Error Protection (UEP) and 16-QAM modulation for EVRC codec of Rate 1 to get power ...