1,721,164 research outputs found
Guest editorial: introduction to the special issue on wireless reconfigurable terminals - Part II
No full textThe first paper of the present issue by Ryynänen et al from Helsinki University of Technology still covers RF hardware implementations aspects giving “an introduction of the demands set by the different systems and receiver architectures to the design of the multi-mode and multi-band receiver”. On the other hand, the last two papers focus on system level issues for future terminals. More specifically, the second paper from Desoli and Filippi from STMicroelectronics “presents an overview of the evolution of mobile terminal architectures, from monolithic to flexible, modular, and capable of meeting the increasing demand for an ever larger number of features at the right cost and time to market”. Finally the third and last paper by Cabric et al. from the University of California, Berkeley takes a more long term view of the terminal evolution addressing spectrum sharing radios that make use of Ultra Wideband transmission and Cognitive techniques
Rinaldo Castello: Trying to balance industry and academia with family life: A pattern of Life?s gifts and trials that combine themselves to make a beautiful picture.
No full textIntroduction to the special issue on wireless reconfigurable terminals
No full textThe first two papers of the present issue are complementary and report the progress of a three year project carried on in the framework of the FIRB program of the Italian Ministry of Research, that will terminate in early 2006 with an involvement of over 150 man-years. The last paper of this first issue comes from a research group at Delft University in the Netherlands that has been among the first to design adaptive RF circuits
A bond-wire inductor-MOS varactor VCO tunable from 1.8 to 2.4 GHz
No full textThis paper presents a technique that optimizes LC-tank CMOS voltage-controlled oscillators (VCOs) by minimizing the product of phase noise and power consumption. Moreover, it shows that the minimum depends on the tank's quality factor Q, the device noise coefficient γ, and the ratio between the maximum oscillation amplitude and supply voltage α. Prototypes, realized in a 0.35-μm process, show the following performances: -122.5 dBc/Hz at 600 kHz from a 1.9-GHz carrier, with 2-V supply voltage and 1-mA current consumption. The VCO can be tuned between 1.8-2.4 GHz, when the varactor control voltage is varied between 0-3.5 V. In the proposed realization, the tank is made of a metal-oxide-silicon varactor (operated between accumulation and deep depletion) and a bond-wire inductor, realized connecting two pads to a package frame lead to be compatible with the production environmen
RC filter for low and very low frequency applications
No full textAn RC filter for low or very low frequency applications, comprising a resistor between the filter input and output, and an amplifier connected after the resistor and having an output fed back to the amplifier input through a capacitor. This simple design allows the known Miller Effect to be utilized to produce a filter having a high time constant while employing small-size components which occupy little space in integrated circuits
A 350µW fifth-order low-pass switched capacitor filter1985 IEEE International Solid-State Circuits Conference. Digest of Technical Papers
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Multimode Reconfigurable Wireless Terminals: a First Step Toward Software Defined Radio
No full textMultimedia applications create the need for multi-mode handsets that support many standards with different frequency, bandwidth, modulation etc. Sharing and/or switching blocks in these handsets are used to extend battery life and/or reduce cost. Furthermore adaptive circuits that can reconfigure themselves within the handover time will enable seamless interoperability over several standards with a single receiver/transmitter. This paper presents RF and analog baseband circuits that are able to support GSM (with Edge), WCDMA (UMTS), WLAN and Bluetooth using reconfigurable building blocks. They can trade power consumption for performance on the fly, depending on the standard and the required quality of service. Experimental measurements in a 0.13 mum CMOS technology are presented and discussed
Supply circuit device for a user's telephone circuit, having a low voltage loss
No full textA circuit is described which comprises an operational amplifier, two resistors connected between the telephone line and the inputs of the amplifier, a capacitor which is charged via a first bipolar transistor controlled by the amplifier via a first FET transistor, a second bipolar transistor in parallel to the connection of the first transistor and the capacitor, a second FET transistor, identical to the first and having its source and gate terminals connected to the corresponding terminals of the first, and two current generators connected to the drain terminals respectively of the first and the second FET transistor and to the bases, respectively, of the first and second bipolar transistor. The currents of the two generators and the other parameters of the circuit are such as to hold the first and second bipolar transistors in a conductive and a switched off state respectively, except when the line voltage fails below a minimum predetermined value; in which case the first and second transistors commute to the switched off and conductive states respectively. The circuit has a lower "voltage loss" than known circuits
Circuit arrangement for enhancing the transconductance of a differential amplifier stage comprising MOS transistors
No full textA circuit arrangement for enhancing the transconductance of a differential amplifier stage comprising a pair of MOS transistors, having respective source electrodes connected together through a circuit node, comprises a pair of active components respectively connected in each of the connections between the aforesaid electrodes and the aforesaid node and serving a characteristic function corresponding to that of a negative value resistor. This arrangement enables the transconductance of the differential stage to be increased while keeping the dissipated electric power low and the area occupied in an integrated circuit small
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