This paper presents a proposal of an Adaptive Equalizer based on DFE, and its implementation in FPGA, to make DVB-S2 transmission reliable under ISI (specially for wideband transmissions) and to make possible the mobile reception over satellite links for QPSK modulation. The Equalizer also presents the potential to reduce the nonlinear distortion effects, which are typically found in the satellite link and is caused by the satellite power amplifiers. This mainly affects high order modulations. The implementation is very flexible because it can make use of CMA and DD algorithms as well as the DVB-S2 header and embedded pilots as training sequences. Its adaptation is performed using the LMS algorithm. The paper presents the proposed architecture and algorithms, the VHDL simulations for AWGN channels and ISI, and the FPGA implementation resource usage. This is the initial step towards an implementation in VLSI.

Design and implementation of signal processing and synchronization algorithms for digital receivers are challenging tasks, especially concerning the verification phase that must cover as many functional tests as possible. This paper discloses the entire internal architecture of the receive chain of the ETSI DVB-S2 digital satellite communication standard and the methodology used for implementing it. It covers architectural, algorithm, and RTL design, together with laboratory set-up, FPGA prototyping and VLSI resource estimation in 65nm CMOS. The result section demonstrates that our approach is able to synchronize and demodulate an 8-PSK DVB-S2 compliant signal, corrupted by all the impairments expected in a digital receiver.

Microstructural design is a widespread approach to tailor the properties of functional materials, with the size effect being an effective constraint that modifies physical phenomena. In this work, we investigate the grain size effect on the properties and the electric field-induced phase transformation behaviour in barium titanate. A broad range of unimodal average grain size distribution between 0.4 µm and 15 µm were successfully sintered avoiding abnormal grain growth. Samples with a grain size close to the range of 1 to 2 µm, balancing microstructural strain, presence and mobility of domain walls to allow the field induced crystal phase transformation, showed optimal electromechanical and dielectric properties. By means of in situ high energy X-ray diffraction and a high-resolution multianalyser detector we distinguish and quantify a tetragonal-orthorhombic phase transformation induced by an electric field, providing unambiguous proof of this induced phase transformation. These results contribute to the understanding of fundamental questions about the piezoelectric effect in barium titanate and consequently other similar systems.