this paper investigates the multiplicative spread spectrum watermarking method for the image. the information bit is spreaded into middle-frequency discrete cosine transform (dct) coefficients of each block of an image using a generated pseudo-random sequence. unlike the conventional signal modeling, we suppose that both signal and noise are distributed with laplacian distribution, because the ...

DSSS (Direct Sequence Spread Spectrum) is one of the main technique of spread spectrum system and is the most common version use for military communication. In this paper, I have designed and implemented RADAR (Radio Wave Detection and Ranging) transmitter and receiver using direct sequence spread spectrum for range estimation. Most challenging part in RADAR system is to be getting better accur...

Abstract The spread spectrum communication method has strong anti-noise and anti-fading capability, but it also brings the problem of low information transmission efficiency. paper proposes a multi-channel M-ary method, using recursive decoding algorithm to reduce bit error rate. In combination with channel equalization technique based on virtual time reversal mirror technique, scheme improves ...