Advanced Electronic Circuits

Tietze, Ulrich; Schenk, Christoph

doi:10.1007/978-3-642-81241-5

Cited by 68 publications

(46 citation statements)

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“…Otherwise, due to the decrease of bandwidth, the pulse width is broadened and the pulse height is reduced. For better lowpass characteristics, we can use Bessel filters [12], [13], whose transfer function is given by…”

Section: B Lowpass Filter For Pulse Preparationmentioning

confidence: 99%

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Negative group delay and superluminal propagation: an electronic circuit approach

Kitano

Nakanishi

Sakamoto

2003

IEEE J. Select. Topics Quantum Electron.

149

146

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Abstract-We present a simple electronic circuit which provides negative group delays for band-limited, base-band pulses. It is shown that large time advancement comparable to the pulse width can be achieved with appropriate cascading of negative-delay circuits but eventually the out-of-band gain limits the number of cascading. The relations to superluminality and causality are also discussed.Index Terms-negative group delay, superluminal propagation, group velocity, filter, causality I. IBrillouin and Sommerfeld showed that in the region of anomalous dispersion, which is inside of the absorption band, the group velocity can exceed c, the light speed in a vacuum, or even be negative [1], [2]. Recently, it was shown that for a gain medium, superluminal propagation is possible at the outside of the gain resonance. Superluminal effects are also predicted in terms of quantum tunneling or evanescent waves [3], [4], [5]. Superluminal group velocities have been confirmed experimentally in various systems, and most controversies over this counterintuitive phenomenon have settled down. However, there seem a several questions remain open; for example, "How far we can speed up the wave packets," "Is it really nothing to do with information transmission," "What kind of applications are possible," and so on. In this paper we will try to solve some of these problems by utilizing a simple circuit model for negative group delays.Negative delay in lumped systems such as electronic circuits is very helpful to understand various aspects of superluminal group velocity. Mitchell and Chiao [6], [7] constructed a bandpass amplifier with an LC resonator and an operational amplifier. An arbitrary waveform generator is used to generate a gaussian pulse by which a carrier is modulated. The circuit basically emulates an optical gain medium which shows anomalous dispersion in off-resonant region. Wang et al. [8] extended this circuit by using two LC resonators which correspond to the two Raman gain lines [9], [10]. At the middle of two gain peaks the frequency dependence of amplitude response is compensated and the pulse distortion can be minimized. The present authors [11] used an operational amplifier with an RC feedback circuit. It provides negative delays for baseband pulses. In previous experiments, optical or electronic, a carrier frequency (ω 0 ) is modulated by a pulse which varies slowly compared with the carrier oscillation and the displacement of the envelopes is measured. Without carriers (ω 0 = 0), the system becomes much more simple. The amplitude response symmetric with respect to zero frequency is helpful to reduce the distortion. The baseband pulse is simply derived from a rectangular pulse generator and a series of lowpass filters.The time constants can easily be set at the order of seconds and we can actually observe that the output LED (light-emitting diode) is lit earlier than the input LED. In addition to the usefulness as a demonstration tool, this circuit turned out to be very convenient to look into the e...

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Section: B Lowpass Filter For Pulse Preparationmentioning

confidence: 99%

“…where Second-order Bessel filters are used in the experiment, because the second-order filter can be realized with an operational amplifier [12], [13]. The circuit diagram is shown in Fig.…”

Section: Lowpass Filters Switchmentioning

confidence: 99%

Negative group delay and superluminal propagation: an electronic circuit approach

Kitano

Nakanishi

Sakamoto

2003

IEEE J. Select. Topics Quantum Electron.

149

146

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“…Each of the stabilized systems will be described below. A simple proportional/derivative (PD) circuit was designed to optimize negative feedback [4]. A combination of proportional and derivative feedback was allowed and the gain was adjustable.…”

Section: Active Negative Feedback Stabilizationmentioning

confidence: 99%

Active and passive stabilization of solid state lasers

et al. 2004

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We present an overview of diode-pumped solid-state lasers with negative feedback stabilization. Active stabilization by means of direct modulation of cavity losses was utilized in several Nd-based quasi-continuous-wave lasers mode-locked by saturable Bragg reflectors (SBR). The stabilization acts to eliminate the relaxation-oscillation-driven spiking after laser oscillation turn-on. Stable continuous-wave modelocking was observed in as little as 10 µs after laser turned on where the leading spike was reduced or completely eliminated dependent on the gain material and the operating wavelength. Stabilization was also used to prevent Q-switching instabilities in a continuous-wave SBR-modelocked Nd:KGW laser resulting in an extended operational parameter range and pulse shortening by up to 35%. Stabilization of passively mode-locked lasers could alternatively be achieved using an intra-cavity element exhibiting nonlinear absorption, which was demonstrated using an Indium Phosphide plate. Pulse shortening by up to 30% was permitted as the modulation depth of the SBR could be increased whilst maintaining stable cw modelocking. Active stabilization was also employed for Tm-based lasers emitting in the 1.9 -2 µm wavelength region as these lasers suffer from inherent amplitude instability and sensitivity to cavity perturbation. Passive stabilization of a Tm:YAlO laser utilizing a germanium plate was also investigated.

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“…For example, one can excite the real system with a square wave and tune the parameters to get an appropriate transient and DC response [21].…”

Section: Pid Controlmentioning

confidence: 99%

FEEDBACK: Theory and Accelerator Applications

Himel

1997

Annu. Rev. Nucl. Part. Sci.

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The use of feedback to stabilize the beam and improve the performance of accelerators is becoming more common. The methods used to design the feedback algorithms are introduced and some practical implementation details are described. The design of a PID loop using classical control techniques is covered as is the design of an optimal controller using modern control theory. Some adaptive control techniques are also briefly described. Examples are given of multiple-input-multiple-output loops and of how to handle systems of many interacting feedback loops.

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Advanced Electronic Circuits

Cited by 68 publications

References 0 publications

Negative group delay and superluminal propagation: an electronic circuit approach

Negative group delay and superluminal propagation: an electronic circuit approach

Active and passive stabilization of solid state lasers

FEEDBACK: Theory and Accelerator Applications

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