Graham Wade

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— This paper investigates the design and application of data magnitude modulation to reduce power amplifier back-off for QPSK and OQPSK modulations for small satellite Earth stations. The coefficients for data magnitude modulation are obtained by using an iterative design loop. The parameters of this loop are tuned to obtain maximum gain. Roll-off factors(More)
– The objective of this project is to maximise the power and bandwidth efficiency of small satellite earth communication terminals whose main limitation to satellite capacity is a non linear transmitting power amplifier. A form of envelope equalisation is presented in which regular QPSK modulation is used together with instantaneous data magnitude(More)
This paper describes a high capacity blind video watermarking system invariant to geometrical attacks such as shift, rotation, scaling and cropping. A spatial domain reference watermark is used to obtain invariance to geometric attacks by employing image registration techniques to determine and invert the attacks. A second, high capacity watermark, which(More)
— Constant envelope and high spectral efficiency are among some of the properties which make continuous phase modulation (CPM) a preferred choice for many applications. Numerous methods are available for designing concatenated CPM systems to achieve additional coding gains. In this paper, we propose a new serial concatenated CPM scheme. Our design uses a(More)
—Walsh filtering has been used as a method to reduce receiver complexity in several coding and modulation systems, especially in continuous phase modulation systems. In this paper, we show that its lowpass filtering ability is poor and alias components arising from an adjacent channel can significantly degrade the maximum-likelihood decoding. Instead, a(More)
The paper discusses the limits of error correction coding for spread spectrum-based video watermarking. The error correction code has as input the watermark data bits and as output the values which will be scaled and used to modify the video pixels (transform coefficients). The data rate of the watermark can increase only at the expense of increasing code(More)
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