Topic
Frequency response
About: Frequency response is a research topic. Over the lifetime, 25705 publications have been published within this topic receiving 332249 citations.
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Patent•
24 Apr 1991TL;DR: In this paper, a passive test probe apparatus 100 which provides high impedance and a relatively flat frequency response over a wide bandwidth is described, which employs a low capacitance probe tip 102 designed to minimize stray probe tip capacitance.
Abstract: A passive test probe apparatus 100 which provides high impedance and a relatively flat frequency response over a wide bandwidth. The probe apparatus 100 uses standard, non-lossy coaxial cable 130. The probe apparatus 100 employs a low capacitance probe tip 102 designed to minimize stray probe tip capacitance. The probe apparatus 100 uses a front-end (tip) resistor R t in series with a conventional RC tip network 240. The tip resistor R t provides two functions: First, it establishes a minimum input impedance for the probe input, and secondly, it provides approximately 80% of the high frequency attenuation when working into the cable characteristic impedance. In addition, a technique is described for determining an optimum length of coaxial cable 130 to be used in the probe apparatus 100. When the cable length is selected in accordance with the present invention, the crossover dip and other transmission line signal distortion effects are minimized.
88 citations
16 Jun 2005
TL;DR: An approach to automated digital controller design for switching power converters is presented, starting from an experimentally identified frequency response, and parameters of the converter transfer function are estimated using a least logarithmic squares method.
Abstract: This paper presents an approach to automated digital controller design for switching power converters. Starting from an experimentally identified frequency response, parameters of the converter transfer function are estimated using a least logarithmic squares method. A direct digital design method then yields a compensator that results in the desired closed loop response. Application of the method is illustrated on an experimental digitally controlled 90 W DC-DC forward converter
88 citations
Patent•
22 Dec 1997
TL;DR: In this paper, a desired frequency response of a microwave network on a monolithic microwave integrated circuit (MMIC), a MIC, or a hybrid circuit is achieved by selectively switching MEM switches to change the network topology.
Abstract: A desired frequency response of a microwave network on a monolithic microwave integrated circuit (MMIC), a microwave integrated circuit (MIC), or a hybrid circuit is achieved by selectively switching MEM switches to change the network topology. In a filter network, MEM switches connected between capacitors and inductors are selectively switched to change the network configuration to achieve a desired frequency response. In an amplifier network, the MEM switches are selectively switched to tune the amplifier to a desired frequency response and to reduce harmonic output.
88 citations
TL;DR: In this article, the authors investigated the design of ultrawideband absorbers with bandwidth ratios larger than 10:1 and showed that if there is no constraint on the total thickness of the absorber, achieving large bandwidths is straightforward.
Abstract: Design of ultrawideband absorbers with bandwidth ratios larger than 10:1 is investigated. It is explained that if there is no constraint on the total thickness of the absorber, achieving large bandwidths is straightforward. The problem becomes challenging when the minimization of the total thickness is considered. It is shown that for a given frequency response, the total thickness of a nonmagnetic absorber cannot be less than a theoretical limit. If a design method can reduce the total thickness to the theoretical limit level, its superiority over other design methods is doubtless. It is demonstrated that the capacitive circuit absorber approach has this unique feature. In order to clarify the design ideas and techniques, the optimal absorber is developed in different stages. It is shown that unequal periods for the low-pass frequency selective surfaces are essential for attaining the optimal performance.
88 citations
TL;DR: In this article, a method is described for designing linear multivariable control schemes which have a closed-loop frequency response as close as possible, in a least squares sense, to a desired response.
Abstract: In this paper a method is described for designing linear multivariable control schemes which have a closed-loop frequency response as close as possible, in a least squares sense, to a desired response. After using characteristic gain loci to ensure system stability, the closed-loop Bode array gives easily understood information about the controlled system in terms of bandwidth, speed of response, resonance and interaction. The closed-loop Nyquist array indicates the robustness of the control scheme for sensor failures ; it also indicates the extent to which state and input noise will be suppressed, since the feedback just multiplies the open-loop disturbances by a unit matrix minus the closed-loop frequency response. Bands of Gershgorin and Ostrowski circles are used to indicate the behaviour for changes in the characteristics of more than one sensor at a time. A similar frequency-response array, obtained by breaking the feedback loops next to the actuators instead of next to the sensors, can be used to p...
88 citations