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The following topics are dealt with: arithmetic circuits; ultra-low voltage VLSI; processors; amplifiers; wireless circuits and systems; Nyquist DACs; adaptive signal processing; bio-inspired networks and biomedical applications; communication system architecture; imagers; chaotic circuits; power electronic circuits; cryptography; routing and interconnect; video processing; MIMO circuits and systems;...
An hybrid direct-sequence/slow frequency hopping code-division multiple-access (DS/SFH-CDMA) system operating in Rayleigh fading is described and its spectral efficiency is estimated in terms of the theoretically achievable average channel capacity (in the sense of information theory) per user. The analysis covers the operation over a broadcast cellular time-varying link and leads to a simple novel...
Digit-serial/parallel multipliers with improved throughput and latency are presented. The multipliers are based on unfolded bit-serial/parallel multipliers. The unfolding yields long critical paths that are reduced by splitting the multiplication as a sum of partial multiplications. Using a sum of two partial multiplications yields an increased throughput with between 50 and 120 percent and the latency...
The latest video coding standard H.264 has been recently approved and has already been adopted for numerous applications including HD-DVD and satellite broadcast. To allow interconnectivity between different applications using H.264, transcoding will be a key factor. When requantizing a bit stream the incoming coding decisions are usually kept unchanged to reduce the complexity, but it can have a...
In this paper we present a portable PDA-based fetal heart monitor that is able to provide instantaneous fetal heart rate (FHR) for the pregnant women. Several signal processing techniques are implemented in our device to make it clear, reliable and ease-to-use. Firstly the spectral subtraction method is used to remove the stationary background noise and the amplitude modulation technique is then employed...
This paper considers the problem of blind adaptive equalization of single-input multiple-output IIR channels without requiring the channel diversity condition. That is, the parallel sub-channels in the fractionally sampled model can have common factors. We develop an equalizer based on IIR prediction of the received signal. The predictor parameters are estimated by using the recursive extended least...
In this paper an improved whitening scheme is first developed by estimating the signal subspace jointly from a set of diagonalization-structural matrices based on the proposed cyclic maximizer of an interesting cost function. Next, a biquadratic contrast function is proposed for extracting one single independent component from a slice matrix group of any order cumulant of the array signals in the...
This paper deals with the experimental validation of the bifurcation analysis for a hysteresis circuit oscillator, obtained by means of both a proper circuit implementation and a measurement setup used for the automatic generation of 1D-bifurcation diagrams. The obtained circuit-based results show an excellent qualitative agreement with the numerical results
A ring oscillator normally has multiple phase outputs which can be programmed into different frequencies with adjustable phase. This idea is implemented into "flying-adder" architecture (Mair and Xiu, 2000). However, this architecture has a timing violation issue and the phase synthesis range only covers half cycle of the output clock. This paper proposed an improved architecture in which...
The real-time modeling of large systems of spiking neurons is computationally very demanding in terms of processing power, synaptic weight memory requirements and communication throughput. We propose to build a high-performance computer for this purpose with a multicast communications infrastructure inspired by neurobiology. The core component is a chip multiprocessor incorporating some tens of small...
In this paper, we investigate the possibility of using simple multimodality sensors to automatically detect a person's sleep condition. Sleep latency and sleep efficiency are critical to both sleep-related diseases and sleep quality measurements. We propose a system which consists of heart-rate, video, and audio sensors, and apply machine learning methods to infer the sleep-awake condition during...
The efficacy of cognitive radio (CR) networks is defined by the ability of radio terminals and their network management systems to identify and classify co-channel interference and propagation dependent degradation. Isolating these phenomena and gathering statistical information about their behavior is a required step if cognitive control algorithms are to be effective in achieving spectrum sharing...
This paper describes a 12-bit 300 MHz CMOS DAC for high-speed system applications. The proposed DAC consists of a unit current-cell matrix for 8 MSBs and a binary-weighted array for 4 LSBs. In order to ensure the linearity of DAC, a double centro symmetric current matrix is designed by using the Q2 random walk strategy. To minimize the feedthrough and improve the dynamic performance, the drain of...
This paper describes the design and implementation of a low-voltage high-frequency variable gain amplifier in a 0.35-mum CMOS technology. The proposed circuit employs source degeneration and current feedback techniques to achieve high linearity and wide bandwidth. Experimental results show that the overall amplifier (including output voltage buffer) has a linear-in-dB controllable gain range of 40-dB...
Approximation and design methods of a general class of IIR complex functions without any required symmetrical property are examined. A set of routines has been developed to allow arbitrary amplitude approximation of such asymmetrical functions. Approximation routines will include such features as high-order touch points in both passband and stopband regions, fixed poles and zeros and arbitrary frequency...
Recently it was shown that a linear precoder can greatly improve the performance of OFDM systems. In this paper, we study linear precoder for space-time coded OFDM (ST-OFDM) system for multiple antenna transmission. The effect of a linear precoder is analyzed when the ST-OFDM system suffers from intersymbol interference caused by undetected channel variations. For QPSK modulation, the optimal precoder...
In this paper, we propose and derive a linear model of a closed-loop PWM class D amplifier (CDA) to model its power supply rejection ratio (PSRR). On the basis of the proposed model, we derive a simple expression that depicts the effects of 3 critical parameters on PSRR: the gain of the integrator, the gain of the PWM stage and the feedback factor. We recommend, from a practical viewpoint, that the...
Nonlinearity has long been recognized as a problem endemic in power amplifiers (PA) with a high power. Digital predistortion (DPD) is one of most effective method to solve this problem. The D/A conversion accuracy on the performance of DPD for RF PA is tested in a hardware platform. The device under test is an actual working 30W PA operating at 881.5 MHz. An in-house DPD algorithm is implemented on...
This paper describes a 155Mbps self-calibrating direct transmitter for Ka-band satellite communications. It uses an 8-PSK modulation to fit the data rate of 155Mbps into a 72MHz channel bandwidth, and employs an adaptive pre-compensation technique to maximize the LO and image suppressions. An FPGA implements the 8-PSK mapper, the pulse-shaping filters and the pre-compensation, while a DSP adaptively...
The design and fabrication of an integrated 1GHz surface acoustic wave (SAW) resonator is described in this paper. The SAW resonator was fabricated using a combination of CMOS plus surface micromachining techniques. Utilizing the minimum feature size of the available 0.6 micron AMI CMOS process, the periodic distance of the interdigitated fingers of the SAW resonator was designed to create an ultra...
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