We consider the problem of optimally allocating local feedback to the stages of a multistage amplifier. The local feedback gains affect many performance indices for the overall amplifier, such as bandwidth, gain, rise-time, delay, output signal swing, linearity, and noise performance, in a complicated and nonlinear fashion, making optimization of the feedback gains a challenging problem. In this paper we show that this problem, though complicated and nonlinear, can be formulated as a special type of optimization problem called geometric programming. Geometric programs can be solved globally and efficiently using recently developed interior-point methods. Our method therefore gives a complete solution to the problem of optimally allocating local feedback gains, taking into account a wide variety of constraints. 1 1

For applications involving the control of moving vehicles, the recovery of relative motion between a camera and its environment is of high utility. This thesis describes the design and testing of a real-time analog vlsi chip which estimates the focus of expansion (foe) from measured time-varying images. Our approach assumes a camera moving through a fixed world with translational velocity; the foe is the projection of the translation vector onto the image plane. This location is the point towards which the camera is moving, and other points appear to be expanding outward from. By way of the camera imaging parameters, the location of the foe gives the direction of 3-D translation. The algorithm we use for estimating the foe minimizes the sum of squares of the differences at every pixel between the observed time variation of brightness and the predicted variation given the assumed position of the foe. This minimization is not straightforward, because the relationship between the brightn...

this paper.

We discuss two control problems that arise in connection with Cartesian feedback radio-frequency power amplifiers. New solutions to both problems are described, and the results of a working prototype are presented. The prototype, a integrated circuit (IC) fabricated in National Semiconductor’s 0.25µm CMOS process, represents the first known fully integrated implementation of the Cartesian feedback concept. 1

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Abstract—A phase-alignment system is used in the first reported IC to fully integrate a power amplifier, Cartesian feedback linearization circuitry, and a phase-alignment system. The phase-alignment system consumes 8.8 mW from a 2.5-V supply and employs a new technique for offset-free analog multiplication that enables it to function without manual trimming. Phase alignment of better than 9 is maintained for drifts as large as 90. We demonstrate how the phase-alignment system improves the stability margins of the fully integrated Cartesian feedback system. The power amplifier itself, integrated on the same die, operates at 2 GHz and delivers a maximum of 14.2 dBm of output power into a 50- load. The IC was fabricated in a 0.25- m CMOS process. Index Terms—Analog multipliers, Cartesian feedback, chopper stabilization, phase alignment, power amplifiers (PAs).

We consider the problem of optimally allocating local feedback to the stages of a multistage amplifier. The local feedback gains affect many performance indexes for the overall amplifier, such as bandwidth, gain, rise time, delay, output signal swing, linearity, and noise performance, in a complicated and nonlinear fashion, making optimization of the feedback gains a challenging problem. In this paper, we show that this problem, though complicated and nonlinear, can be formulated as a special type of optimization problem called geometric programming. Geometric programs can be solved globally and efficiently using recently developed interior-point methods. Our method, therefore, gives a complete solution to the problem of optimally allocating local feedback gains, taking into account a wide variety of constraints. Index Terms---Amplifiers, analog circuits, circuit optimization, design automation, geometric programming, sensitivity. I.

1 All you really need to know about device physics to design bipolar junction transistor circuits... To design useful transistor circuits, it is important to understand the detailed operation of the bipolar junction device. Ideally, that understanding includes the device physics responsible for the transistor’s behavior. Deep knowledge of the physics provides the designer with a solid foundation to understand the circuit models and the trade-offs used in design.

Abstract — A cart with two independent inverted pendula, called a dual-inverted-pendulum system, is analyzed and compared to the single-inverted-pendulum system using classical linear methods. Using only the angles of the pendula and the position of the cart, a classical controller is designed that stabilizes the pendula in the inverted position with the cart at the center of the track. Simulations of the transient response to initial conditions are presented. Intuitive reasoning and an insightful approach to the control design are major emphases of this effort. x lL θL θB lB I.