Referenced Approximation Technique for a Rom-Less Sweep Frequency Synthesizer

The main goal of this paper is to present a novel ROM-less direct digital frequency synthesizer for sweep instrumentation systems. It provides a main sweep channel for frequency analysis and a reference channel for phase and amplitude measurement block operating at constant frequency. For phase to amplitude converter, we propose a new trigonometric approximation technique based on a set of reference angles. In addition, we present the design of the proposed synthesizer and its evaluation in Matlab-Simulink environment. The simulation results illustrate the performances and demonstrate the effectiveness of our proposed circuit

Comparison between Trigonometric, and traditional DDS, in 90 nm technology

The Direct Digital frequency Synthesizer (DDS) is an architecture largely used for the generation of numeric sine and/or cosine waveforms in different applications. In this work, authors compare two different DDS architectures: the traditional architecture, based on the exploitation of quarter wave symmetry, and the Symon’s DDS (trigonometric DDS) presented in 2002. The two layout configurations have been implemented in 90 nm technology and compared in terms of area, speed and power consumption. Comparisons have been performed in terms of circuital complexity on architectures having the same Spurious Free Dynamic Range (SFDR) and phase resolution. Experiments show that the trigonometric architecture is very efficient in terms of area

Transceiver architectures and sub-mW fast frequency-hopping synthesizers for ultra-low power WSNs

Wireless sensor networks (WSN) have the potential to become the third wireless revolution after wireless voice networks in the 80s and wireless data networks in the late 90s. This revolution will finally connect together the physical world of the human and the virtual world of the electronic devices. Though in the recent years large progress in power consumption reduction has been made in the wireless arena in order to increase the battery life, this is still not enough to achieve a wide adoption of this technology. Indeed, while nowadays consumers are used to charge batteries in laptops, mobile phones and other high-tech products, this operation becomes infeasible when scaled up to large industrial, enterprise or home networks composed of thousands of wireless nodes. Wireless sensor networks come as a new way to connect electronic equipments reducing, in this way, the costs associated with the installation and maintenance of large wired networks. To accomplish this task, it is necessary to reduce the energy consumption of the wireless node to a point where energy harvesting becomes feasible and the node energy autonomy exceeds the life time of the wireless node itself. This thesis focuses on the radio design, which is the backbone of any wireless node. A common approach to radio design for WSNs is to start from a very simple radio (like an RFID) adding more functionalities up to the point in which the power budget is reached. In this way, the robustness of the wireless link is traded off for power reducing the range of applications that can draw benefit form a WSN. In this thesis, we propose a novel approach to the radio design for WSNs. We started from a proven architecture like Bluetooth, and progressively we removed all the functionalities that are not required for WSNs. The robustness of the wireless link is guaranteed by using a fast frequency hopping spread spectrum technique while the power budget is achieved by optimizing the radio architecture and the frequency hopping synthesizer Two different radio architectures and a novel fast frequency hopping synthesizer are proposed that cover the large space of applications for WSNs. The two architectures make use of the peculiarities of each scenario and, together with a novel fast frequency hopping synthesizer, proved that spread spectrum techniques can be used also in severely power constrained scenarios like WSNs. This solution opens a new window toward a radio design, which ultimately trades off flexibility, rather than robustness, for power consumption. In this way, we broadened the range of applications for WSNs to areas in which security and reliability of the communication link are mandatory

A BIST solution for frequency domain characterization of analog circuits

This work presents an efficient implementation of a BIST solution for frequency characterization of analog systems. It allows a complete characterization in terms of magnitude and phase, including also harmonic distortion and offset measurements. Signal generation is performed using a modified filter, while response evaluation is based on 1storder ÓÄ modulation and very simple digital processing. The signal generator and the response analyzer have been implemented using the Switched-Capacitor (SC) technique in a standard 0.35ìm-3.3V CMOS technology. Both circuits have been separately validated, and an on-board prototype of the complete test system for frequency characterization has been implemented. Experimental results verify the functionality of the proposed approach, and a dynamic range of [email protected] (1MHz clock) has been demonstrated.Gobierno de España TEC2007-68072/MIC, TSI 020400- 2008-71Catrene European Project 2A105SR

Theory, design and implementation of an IF cancellation module for use in a stepped frequency continuous wave ground penetrating radar

Bibliography: leaves 64-68.A device has been designed that cancels the leakage signal between the transmit and receive antenna in a Stepped Frequency Continuous Wave Ground Penetrating Radar. The front end of the radar operates at high signal levels and, as a result, a large signal is coupled directly from the transmit to the receive antenna. This signal uses a signiï¬ cant part of the dynamic range of the data-capturing device, an analogue-to-digital converter (ADC). The objective of this cancellation is thus to increase the effective instantaneous dynamic range of the radar system. Simulations show that 10-bit amplitude and phase resolution in the digital cancellation circuit would achieve maximum cancellation in the presence of phase noise and other sources of error. This result is conï¬ rmed when the hardware is tested. The device was constructed and operates as intended. Tests show that cancellation exceeding 53dBm is possible through careful calibration. It was concluded that the device could successfully be integrated into the SFCW GPR and that it would achieve an increase in the instantaneous dynamic range