In orthogonal frequency division multiplexing (OFDM) systems with differential phase shift keying (DPSK), it is possible to apply differential modulation either in the time or frequency domain depending on the condition of fading channels, such as the Doppler frequency shift and the delay spread. This paper proposes a simple calculation method, that is, an approximate closed-form equation of th...

This article presents a novel algorithm based on the cross-Wigner-Ville Distribution (XWVD) for optimum phase estimation within the class of phase shift keying signals. The proposed method is a special case of the general class of cross time-frequency distributions, which can represent the phase information for digitally phase modulated signals, unlike the quadratic time-frequency distributions...

This paper is focusing on development of ZigBee transceiver at physical layer using IEEE 802.15.4. ZigBee technology was developed for a wireless personal area networks (PAN), aimed at control and military applications with low data rate and low power consumption. ZigBee is a low-cost, low-power, wireless mesh networking standard. First, the low cost allows the technology to be widely deployed ...

The High Rate Baseband Multi-Modulator (HRBM) ASIC is being developed to provide High-Speed Bandwidth Efficient Modulations to NASA missions. Bandwidth efficiencies from 2.0 bits/symbol/Hz to 2.75 bits/symbol/Hz are selectable from three CCSDS modulations: Gaussian Minimum Shift Keying (GMSK), Filter Offset Quadrature Phase Shift Keying (Filtered-OQSK) and 8-Phase Shift Keying Trellis Coded Mod...

This paper describes the recent advances in semiconductor photodiodes for use in ultra-high-speed optical systems. We developed two types of waveguide photodiodes (WG-PD) — an evanescently coupled waveguide photodiode (EC-WG-PD) and a separated-absorption-andmultiplication waveguide avalanche photodiode (WG-APD). The EC-WGPD is very robust under high optical input operation because of its distr...