We report on quadrature demultiplexing of a quadrature phase-shift keying (QPSK) signal into two cross-polarized binary phase-shift keying (BPSK) signals with negligible penalty at bit-error rate (BER) equal to 10(-9). The all-optical quadrature demultiplexing is achieved using a degenerate vector parametric amplifier operating in phase-insensitive mode. We also propose and demonstrate the use ...

The sphere decoder (SD) is a powerful algorithm to reduce the computational complexity for multiple-symbol differential detection (MSDD) of differential phase-shift keying. To further increase the quality of the transmission, soft-output sphere decoding produces reliability information in the form of LLRs which are fed into the channel decoder. In this paper, we compare the basic SD algorithm w...

π/4-DQPSK (π/4-differential quadrature phase shift keying), the scheme using nonredundant multiple error correction is proposed and investigated. This scheme for the differential detection of π/4-DQPSK uses the signal output which is delayed for more than two time slots as the parity check bit and applies it to nonredundant multiple error correction. The proposed system was used for studying th...

This paper describes a design of signal generator based on direct digital synthesis technique (DDS). According to the basic principles of DDS using Matlab/DSP Builder establish DDS model, then compiling by the SignalCompiler tools and generating VHDL code. Finally download the relevant documents to the field programmable gate array (FPGA) chip EP2C5Q208C8N. EP2C5Q208C8N and digital-analog chip ...

M-ary On-Off Frequency-Shift-Keying (OOFSK) is a digital modulation format in which M-ary FSK signaling is overlaid on On/Off keying. This paper investigates the potential of this modulation format in the context of wideband fading channels. First it is assumed that the receiver uses energy detection for the reception of OOFSK signals. Capacity expressions are obtained for the cases in which th...