Mixed-Signal Multimode Radio Software/Hardware Development Platform

Radio frequency power amplifiers (PAs) are the most challenging part of the design of radio systems since they dictate the overall system's performance in terms of power efficiency and distortion generation. The performance is further challenged by modern modulation schemes which are characterized by highly varying signal envelopes. In order to meet the spectrum mask requirements, PAs are usually operated at high power back-off to ensure linearity, at the cost of efficiency. To tackle this issue, many efficiency enhancement techniques have been presented in the literature. In fact, these techniques do increase the PA power efficiency at back-off, however, efficiency enhancement techniques do not ensure the linearity of the PA. Furthermore, these techniques may lead to additional distortion. On the other hand, several linearization techniques have been developed to mitigate the PA nonlinearity problem and allow the PA to operate at less back-off. Digital Pre-Distortion (DPD) technique is gaining more attention, as compared to other linearization techniques, thanks to its simple concept and advancements in digital signal processors (DSP) and signal converters. DPD technique consists of introducing a nonlinear function before the PA so that the overall cascaded system behaves linearly. It was clear from the literature that this technique showed good performance. Yet, it has primarily been validated using commercial test equipment, which has good capabilities, and far from the real world environment in which this technique would be implemented. Indeed, DPDs would need to be implemented in signal processors characterised by limited resources and computational accuracy. This thesis presents an implementation of several DPD models, namely look-up table (LUT), memoryless polynomial and memory polynomial (MP), on a field programmable gate array (FPGA). A novel model reformulation made this implementation possible in fixed-point arithmetic. Measurements were collected to validate the DPD models' implementation and an improvement of the signal quality was recorded in terms of error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR). As many wireless access technologies must continue to coexist, multi-standard radio systems are required to reduce the cost while maintaining the interoperability. This thesis presents a development platform for multimode radio which comprises mixed-signal modules. The platform provides the capacity for hardware and software development. In fact, the FPGA under investigation allowed for the implementation of a baseband transceiver and DPD schemes. In addition, a software tool was developed as a dashboard to control and monitor the system. The radio system in the platform was optimized through the equalization of the feedback receiver frequency response performed through a simultaneous measurement of the amplitude ripple of the transmitter and receiver. Furthermore, a phase-coherent frequency synthesizer was designed to bring more flexibility by allowing the transmitter's carrier frequency to be different from the receiver's frequency

Quality attributes of Bearss Seedless lime (Citrus latifolia Tan) juice during storage.

The composition of three types of date juices, that differs by their couple of extraction and obtained from the rest of the sorting of cultivars Deglet Nour, were studied. The fruits were grown in Djerid region (Tozeur, Tunisia). Juices were characterised by yield, pH, soluble solids, organic acid, minerals content, individual carbohydrates, vitamin C, yeasts and moulds, coliforms and flora total aerobe contents. For the physicochemical parameters, only the J3 presents the best yields with content in citric acid of 2.13 g L-1, in phosphor of 0.083% (dry mater), in glucose 26.529 g L-1, in fructose 39.59 g L-1 and in sucrose 185.883 g L-1. For the bacteriological parameters, the results show that all prepared juices answer the microbiological requirements of hygiene well

Antioxidant, free radical scavenging and anti-inflammatory effects of aloesin derivatives in Aloe vera.

The chemical analysis of flesh and pit of two varieties of date palm fruit (Deglet nour and Alig) as well as the radical scavenging activity of their extracts was undertaken. The fruits were grown in Djerid region (Oasis of Tozeur, Tunisia). Total sugars was measured by HPLC method or with Fehling reagent, crude lipid content was obtained by Soxhlet’s extraction, mineral elements were measured by atomic absorption photometer. The antioxidant activity of extracts from the flesh and pit of the date fruit was measured on the basis of the scavenging activity of the stable 1, 1-diphenyl-2-picrylhy-drazyl (DPPH) free radical. Our results showed that the total sugars could present over 60% of the dry weight of date flesh in two studied varieties. The content of reducing sugars was higher in Alig variety than Deglet nour. For the minerals content, dates flesh were a very good source of several minerals and could be an important