Based on a novel class of orthogonal pulse pairs, new full-response quadrature-quadrature phase-shift keying (QPSK) signal format is proposed in the paper. The proposed full-response QPSK signals can provide higher spectral compactness than conventional fullresponse QPSK signal, minimum-shift keying signal and quadrature phase-shift keying signal.

a direct-sequence signal with binary phase-shift keying (BPSK) or differential block diagram of direct-sequence systemn with BPSK or DPSK: a transmitter. Differential Phase Shift Keying. ▫ For a standard telephone circuit with S/N of 3000 (30. dB) and A block diagram of a QPSK modulator is shown in the next. differential phase shift keying (DPSK) modulations is that both Block diagram of the ge...

Modulation plays an important role in transmission of signals from transmitter to receiver in all communication systems and the performance of digital modulation systems is of the most important key factors to achieve the best results of the communication process . This paper presents a comparative study of some performance parameters or performance metrics of a digital communication system wit...

Usage of the benefits of electrical communication has become an inseparable part of our lives now. Through this paper, I have tried to summarize various technologies that are important in the field of digital communication and have also included the recent advancements in the same field. The paper starts with the basic idea about the communication system followed by basic modulation techniques ...

in this paper first we try to analysis the behavior ofthe soas in the optical networks and then have proposed anumerical simple model to simulate the behavior of thesemiconductor optical amplifiers. after that by employing thismodel as inline amplifier for a dwdm optical system, we havesimulated the transmission of 10 channels with bit rate 10 gb/sup to distance 3970 km with rz-dpsk modulation ...

As a special case of continuous phase frequency-shift-keying (FSK), minimum-shift keying (MSK) exhibits some different properties compared with the traditional optical phase modulation formats, such as return-to-zero (RZ) differential-phase-shift-keying (DPSK) and differential-quadrature-phase-shift-keying (DQPSK). In this paper, we investigated the receiver performance degradation caused by la...

With the growing demand in modern communication, it has become necessary to give better and efficient service to users by using better technique. Technique such as Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Differential Phase shift Keying (DPSK) and Quadrature Amplitude Modulation (QAM) are very important parts of the implementation of modern communica...

in this paper first we try to analysis the behavior ofthe soas in the optical networks and then have proposed anumerical simple model to simulate the behavior of thesemiconductor optical amplifiers. after that by employing thismodel as inline amplifier for a dwdm optical system, we havesimulated the transmission of 10 channels with bit rate 10 gb/sup to distance 3970 km with rz-dpsk modulation ...

In this paper, a precise method for calculating the bit-error rate (BER) of a discrete cosine transform (DCT)-based orthogonal frequency-division multiplexing (OFDM) system on additive white Gaussian noise (AWGN) channels for a Multicarrier-CDMA (MCCDMA) is derived and its BER performance will be compared with the FFT based MC-CDMA. These accurate results are used to examine and compare the BER...