Spread Spectrum

Maximum-length sequence (m-sequence) generator

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Key focus: Model and simulate m-sequence generator using Galois linear feedback shift registers (LFSR) that implement linear recursion. Plot correlation properties. Maximum-length sequences (also called as m-sequences or pseudo random (PN) sequences) are constructed based on Galois field theory which is an extensive topic in itself. A detailed treatment on the subject of Galois field theory … Read more

Gold code generator using LFSRs

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Focus of this article is to discuss the details of Gold code generator using preferred pair m-sequences, implemented using linear feedback shift registers (LFSR). Finally we plot and investigate correlation properties of the generated Gold codes. Introduction In a multi-user environment (like spread spectrum, CDMA ) large number of codes with good correlation properties, is … Read more

Walsh Hadamard Code – Matlab Simulation

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The following is a function to generate a Walsh Hadamard Matrix of given codeword size. The codeword size has to be a power of 2. function [H]=generateHadamardMatrix(codeSize) %[H]=generateHadamardMatrix(codeSize); % Function to generate Walsh-Hadamard Matrix where “codeSize” is the code % length of walsh code. The first matrix gives us two codes; 00, 01. The second … Read more

Spread Spectrum Communications – Introduction

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Spread spectrum system, originally developed for military applications, is extremely resistant to unauthorized detection, jamming, interference and noise. It converts a narrowband signal to wideband signal by the means of spreading. Standards like WiFi and bluetooth use spread spectrum technology such as direct sequence spread spectrum and frequency hopping spread spectrum respectively. Spread spectrum techniques … Read more