IEEE Transactions on Circuits and Systems I: Regular Papers

In this paper, we investigate the effect of low-frequency active feedback in the 1/f phase modulation (PM) noise of a linear SiGe heterojunction bipolar transistor amplifier operating at 1 GHz. The voltage gain and the output resistance of the feedback amplifier were varied and their effect on the baseband collector voltage noise reduction and PM noise reduction were observed. Our results show tha... View full abstract»

This paper presents intuitive yet quantitative insights into the harmonics of analog-to-digital converter (ADC) output spectra. It derives the spectral signatures associated with imperfections in practical ADCs. This understanding leads to remedies based on architecture and time-averaging, which are combined to propose a calibration-free pipeline CMOS ADC that simulations show is capable of better... View full abstract»

This paper reports synthesis methodologies for linear analog circuits. A generalized multi-input operational transconductance amplifier (OTA) network has been synthesized that can be easily programmed to realize different analog functions. The design of the multifunction network has been realized without any switches. The inherent characteristic of OTA as a voltage-to-current (V-I) converter with ... View full abstract»

This paper presents a new method to characterize the behavior of an oscillator's slow-varying modes, e.g., amplitude and phase. Key to the method is the projection of the original set of circuit equations onto the slow manifold defined by the oscillator's core system. The core system corresponds to the terms of the circuit equations that generate the fast-varying oscillations. The corresponding sl... View full abstract»

A new technique of arbitrary waveform direct digital frequency synthesis (DDFS) is introduced. In this method, one period of the desired periodic waveform is divided into m sections, and each section is approximated by a series of Chebyshev polynomials up to degree d. By expanding the resultant Chebyshev polynomials, a power series of degree d is produced. The coefficients of this power series are... View full abstract»

This paper proposes new methods for the efficient design and realization of perfect reconstruction (PR) two-channel finite-impulse response (FIR) triplet filter banks (FBs) and wavelet bases. It extends the linear-phase FIR triplet FBs of Ansari et al. to include FIR triplet FBs with lower system delay and a prescribed order of K regularity. The design problem using either the minimax error or lea... View full abstract»

This paper presents an iterated short convolution (ISC) algorithm, based on the mixed radix algorithm and fast convolution algorithm. This ISC-based linear convolution structure is transposed to obtain a new hardware efficient fast parallel finite-impulse response (FIR) filter structure, which saves a large amount of hardware cost, especially when the length of the FIR filter is large. For example... View full abstract»

This paper presents a detailed empirical study and analytical derivation of voltage waveform and energy dissipation of global lines driven by CMOS drivers. It is shown that at high clock frequencies where the output voltage at the termination point of the transmission line may not reach its steady-state value during the clock period, it is possible to reduce energy dissipation while meeting a dc n... View full abstract»

In this paper, the parallel COrdinate Rotation DIgital Computer (CORDIC) rotation algorithm in circular and hyperbolic coordinate is proposed. The most critical path of the conventional CORDIC rotation lies in the determination of rotation directions, which depends on the sign of the remaining angle after each iteration. Using the binary-to-bipolar recoding (BBR) and microrotation angle recoding t... View full abstract»

In this paper, we present an efficient algorithm to compute singular points and singularity-induced bifurcation points of differential-algebraic equations for a multimachine power-system model. Power systems are often modeled as a set of differential-algebraic equations (DAE) whose algebraic part brings singularity issues into dynamic stability assessment of power systems. Roughly speaking, the si... View full abstract»

This paper presents a sliding-mode control design of a boost-buck switching converter for a voltage step-up dc-ac conversion without the use of any transformer. This approach combines the step-up/step-down conversion ratio capability of the converter with the robustness properties of sliding-mode control. The proposed control strategy is based on the design of two sliding-control laws, one ensurin... View full abstract»

In previous papers, we introduced two modified "Bussgang" algorithms (MBAs) for blind-channel equalization based on Bayesian iterative estimation of the source sequence. They were developed in order to reduce the computational complexity of the original "Bussgang" algorithm as well as to make it more flexible by introducing a kind of source adaptivity. However, the previous work relied on some heu... View full abstract»

The class of stochastic descriptor systems, also named singular systems, has been widely investigated and many important results in the linear filtering theory have been achieved in the framework of Gaussian processes. Nevertheless, such results could be far from optimal, especially in the case of highly asymmetrical non-Gaussian noises. This paper solves the estimation problem for stochastic sing... View full abstract»

Multilevel pulsewidth modulation (PWM) has become very important in high-power applications in recent years. Many different types of topology and control strategy have been developed to cater for the increasing need. One of the major concerns of the control strategy is to reduce the undesirable harmonics in order to improve the performance and efficiency. This paper presents the derivation of anal... View full abstract»

In this paper, a general methodology for predicting the amplitude of oscillation in nearly sinusoidal oscillators is presented. The method relies on the recently proposed projection technique for the computation of the center manifold and on the Hopf normal form theory to approximate the corresponding limit cycle in state space. The Colpitts oscillator is selected as a case study and, for this cir... View full abstract»

State space averaging methods are used to derive time-invariant models that bound the envelope of trajectories of pulsewidth modulated (PWM) dc-dc converters. The results are compared to conventional averaging methods used in power electronics, and it is shown that, at times, designing a dc-dc converter based on the averaged output of a converter can be ineffective because peak output values somet... View full abstract»

A band-limited signal can be recovered from its periodic nonuniformly spaced samples provided the average sampling rate is at least the Nyquist rate. A multirate filter bank structure is used to both model this nonuniform sampling (through the analysis bank) and reconstruct a uniformly sampled sequence (through the synthesis bank). Several techniques for modeling the nonuniform sampling are presen... View full abstract»

In this paper, analysis and design for a single-phase active power filter (APF) with one-cycle control is presented. The proposed control method eliminates the need of sensing the load current, a nontrivial task of calculating the harmonics and reactive current components, as well as the use of multipliers, as reported by many previously reported approaches. In addition, the switching loss is redu... View full abstract»

It is shown that the elements of a large class of periodically varying nonlinear input-output maps can be uniformly approximated arbitrarily well, over infinite time intervals, using a certain structure that can be implemented in many ways using, for example, radial basis functions, polynomial functions, piecewise linear functions, sigmoids, or combinations of these functions. For the special case... View full abstract»

Realization of a loss-free resistor element (i.e., element with resistive input characteristic and yet loss-free) by means of switched mode converters operated in discontinuous current conduction mode (DCM) is presented. Practically, the input characteristic is not pure resistive due to the ripple and filtering effects. A method which enables reduction of the ripple to negligible values and the el... View full abstract»

Recently, multidimensional wave digital filter (MDWDF) structures have been proposed for the modeling of plate vibration problems. In this paper, we discuss how initial and boundary conditions may be properly embedded into such an algorithm in terms of the state quantities that are an integral part of the algorithm. Due to the essential feature of fully-local interconnectivity in the MDWDF model, ... View full abstract»