Advanced Modulation

Digital Modulation – DPSK

The purpose of this lesson is to demonstrate how to design an 8 DPSK pulse generator using the OptiSystem component library. This tutorial includes references to project files that demonstrate some of the steps presented here. Refer to the end of the tutorial for the project file names. You should use the OptiSystem Component Library…

Digital modulation – OQPSK

The OQPSK modulation is a PSK modulation, using 2 bits per symbol and a delay of one bit in the in quadrature signal (refer to OptiSystem component library, OQPSK Pulse Generator). The project file “OQPSK – Transmitter and Receiver.osd” has an OQPSK transmitter and receiver (Figure 1).

Digital modulation – QAM

Introduction The QAM modulation is typically used in CATV system for cable modem transmission. The project file The project file “QAM – Transmitter and Receiver.osd” has an QAM transmitter and receiver (Figure 1) using a 64 QAM transmission (6 bits per symbol). Figure 1: 64 QAM System The main difference from the DPSK project is…

Manchester and PAM Coding/Decoding

A Manchester encoded signal contains frequent level transitions which allow the receiver to extract the clock signal and correctly decode the value and timing of each bit. To allow reliable operation, the transmitted bit stream must contain a high density of bit transitions. Manchester encoding ensures this, allowing the receiving to correctly extract the clock…

Coherent Optical OFDM

RF spectrum for the in-phase component

Orthogonal frequency division multiplexing (OFDM) is a multicarrier transmission technique where a data stream is carried with many lower-rate subcarrier tones…

100 Gbps DP-QPSK System with Digital Signal Processing

Constellation diagram (for polarization X)

The combination of polarization-multiplexing and quadrature phase-shift-keying (PM-QPSK or DP-QPSK) is emerging as one the most promising solutions to reach bit rates of 100 Gbps and higher.