Edge Modulation Research Articles

Measurement of the modulation transfer function of a charge-coupled device array by the combination of the self-imaging effect and slanted edge method

In this paper, by a combination of the self-imaging effect for Ronchi gratings and the standard slanted edge modulation transfer function (MTF) measurement method for CCD cameras, the MTF of the CCD array without optics is measured. For this purpose, a Ronchi-type grating is illuminated by an expanded He-Ne laser. A self-image of the grating appears without optics on the CCD array that is located on the Talbot distance. The lines of the self-image of the grating are used as a slanted edge array. This method has all the advantages of the slanted edge method, and also since the array of the edge is ready, the total area of the CCD can be tested. The measured MTF is related to the CCD array without optics.

The Outphasing RF Power Amplifier: A Comprehensive Analysis and a Class-B CMOS Realization

We present a theoretically comprehensive treatment of outphasing systems that utilize radio-frequency high-efficiency PAs. We separately analyze encoding and clipping distortions and how they accounts for most of the nonlinearities in outphasing systems. With that insight, we have designed an inherently linear outphasing system at high efficiency. We have implemented these techniques in a 90-nm Class-B prototype that uses signal-dependent time-varying circuits under close digital control to achieve 56%, 44%, and 30% efficiency for GSM, EDGE, and WCDMA modulations, while demonstrating linearity commensurate with demanding specifications on adjacent channel leakage.

Form and metabolic scaling in colonial animals

Benthic colonial organisms exhibit a wide variation in size and shape and provide excellent model systems for testing the predictions of models that describe the scaling of metabolic rate with organism size. We tested the hypothesis that colony form will influence metabolic scaling and its derivatives by characterising metabolic and propagule production rates in three species of freshwater bryozoans that vary in morphology and module organisation and which demonstrate two- and three-dimensional growth forms. The results were evaluated with respect to predictions from two models for metabolic scaling. Isometric metabolic scaling in two-dimensional colonies supported predictions of a model based on dynamic energy budget theory (DEB) and not those of a model based on fractally branching supply networks. This metabolic isometry appears to be achieved by equivalent energy budgets of edge and central modules, in one species (Cristatella mucedo) via linear growth and in a second species (Lophopus crystallinus) by colony fission. Allometric scaling characterised colonies of a three-dimensional species (Fredericella sultana), also providing support for the DEB model. Isometric scaling of propagule production rates for C. mucedo and F. sultana suggests that the number of propagules produced in colonies increases in direct proportion with the number of modules within colonies. Feeding currents generated by bryozoans function in both food capture and respiration, thus linking metabolic scaling with dynamics of self-shading and resource capture. Metabolic rates fundamentally dictate organismal performance (e.g. growth, reproduction) and, as we show here, are linked with colony form. Metabolic profiles and associated variation in colony form should therefore influence the outcome of biotic interactions in habitats dominated by colonial animals and may drive patterns of macroevolution.

Magnonic band gap design by the edge modulation of micro-sized waveguides

The potential to control the number of the spin-wave band gaps of a magnonic crystal (MC) by variation of its geometry is investigated by numerical simulations. The MC is represented by a micro-sized planar ferromagnetic waveguide with periodically variable width. By choosing a step-like or sinusoidal variation of the width, the MC reveals multiple or single band gaps, respectively. This allows for additional degrees of freedom in the design of MC-based microwave filters and phase shifters with desired characteristics. The MCs' band gaps have been studied in the space and frequency domains exploring the spin-wave spectrum dependence on the probing position inside the MC.

High-Efficiency Cellular Power Amplifiers Based on a Modified LDMOS Process on Bulk Silicon and Silicon-On-Insulator Substrates With Integrated Power Management Circuitry

An RF high-voltage CMOS technology is presented for cost-effective monolithic integration of cellular RF transmit functions. The technology integrates a modified LDMOS RF power transistor capable of nearly comparable linear and saturated RF power characteristics to GaAs solutions at cellular frequency bands. Measured results for multistage cellular power amplifier (PA) designs processed on bulk-Si and silicon-on-insulator on high-resistivity Si substrates (1 kΩ·cm ) are presented. The low-band multistage PA achieves greater than 60% power-added efficiency (PAE) with more than 35.5-dBm output power. The high-band PA achieves 45%-53% PAE across the band with greater than 33.4-dBm output power. Measured linearity performance is presented using an EDGE modulation source. A dc/dc buck converter was also integrated in the PA die as the power management circuitry. Measured results for the output power, PAE, and spurious emissions in the receive band while the dc/dc converter is biasing the PA and running at different modes are reported.

The finite-size effect on the transport properties in edge-modified graphene nanoribbon-based molecular devices

The size-dependence on the electronic and transport properties of the molecular devices of the edge-modified graphene nanoribbon (GNR) slices is investigated using density-functional theory and Green's function theory. Two edge-modifying functional group pairs are considered. Energy gap is found in all the GNR slices. The gap shows an exponential decrease with increasing the slice size of two vertical orientations in the two edge terminated cases, respectively. The tunneling probability and the number of conducting channel decreases with increasing the GNR-slices size in the junctions. The results indicate that the acceptor-donor pair edge modulation can improve the quantum conductance and decrease the finite-size effect on the transmission capability of the GNR slice-based molecular devices.

Mask line roughness contribution in EUV lithography

In this paper, mask line edge roughness contribution to the final resist roughness is studied. For this purpose, dedicated line and space modules were designed. Both correlated and anticorrelated edge modulations were considered. For each modulation type, frequency and amplitude were varied. Two pitches were exposed with EUV ASML Alpha Demo Tool: 88 and 128nm in both horizontal and vertical direction. Analysis in the frequency domain was done by means of edge detection of top-down resist images.It was found that the lithographic optical system acts as a low pass filter for the mask line edge roughness frequency components: low frequencies mask roughness, lower that the optical system cut-off, were fully transferred on wafer, and characterized by power spectral density analysis. Moreover, it was established that high frequency mask roughness component had a detrimental effect on low frequency resist roughness, due to an aerial image degradation. Optical simulations were run to confirm experimental results.

Low cost, high performance, self-aligning miniature optical systems

The most expensive aspects in producing high quality miniature optical systems are the component costs and long assembly process. A new approach for fabricating these systems that reduces both aspects through the implementation of self-aligning LIGA (German acronym for lithographie, galvanoformung, abformung, or x-ray lithography, electroplating, and molding) optomechanics with high volume plastic injection molded and off-the-shelf glass optics is presented. This zero alignment strategy has been incorporated into a miniature high numerical aperture (NA = 1.0 W) microscope objective for a fiber confocal reflectance microscope. Tight alignment tolerances of less than 10 microm are maintained for all components that reside inside of a small 9 gauge diameter hypodermic tubing. A prototype system has been tested using the slanted edge modulation transfer function technique and demonstrated to have a Strehl ratio of 0.71. This universal technology is now being developed for smaller, needle-sized imaging systems and other portable point-of-care diagnostic instruments.

Predictive Digital-Controlled Converter With Peak Current-Mode Control and Leading-Edge Modulation

The main theme of this paper is to present the digital controller design of a power converter with predictive peak current-mode (PCM) control and leading-edge modulation. The advantages of the control and modulation technique include the reduction of the sampling frequency of the A/D converter, no need of slope compensation, and the provision of a fast dynamic current response. The discrete-time model of the converter is presented as the fundamental to digital controller design and followed by the digital controller design. Moreover, the effect of predictive PCM control with leading edge modulation on limit cycle is analyzed. It is known that the limit cycle can be effectively suppressed as the converter has a predictive PCM control and leading edge modulation. Experimental results will be included to support fully the theoretical analysis.

Evaluation of motion performance on scanning‐backlight LCDs

The scanning‐backlight technique to improve the motion performance of LCDs is introduced. This technique, however, has some drawbacks such as double edges and color aberration, which may become visible in moving patterns. A method combining accurate measurements of temporal luminance transitions with the simulation of human‐eye tracking and spatiotemporal integration is used to model the motion‐induced profile of an edge moving on a scanning‐backlight LCD‐TV panel that exhibits the two drawbacks mentioned above. The model results are validated with a perception experiment including different refresh rates, and a high correspondence is found between the simulated apparent edge and the one that is perceived during actual motion. Apart from the motion‐induced edge blur, the perception of a moving line or square‐wave grating can also be predicted by the same method starting from the temporal impulse and frame‐sequential response curves, respectively. Motion‐induced image degradation is evaluated for both a scanning‐ and continuous‐backlight mode based on three different characteristics: edge blur, line spreading, and modulation depth of square‐wave grating. The results indicate that the scanning‐backlight mode results in better motion performance.

Evaluation of motion performance on scanning‐backlight LCDs

Abstract— The scanning‐backlight technique to improve the motion performance of LCDs is introduced. This technique, however, has some drawbacks such as double edges and color aberration, which may become visible in moving patterns. A method combining accurate measurements of temporal luminance transitions with the simulation of human‐eye tracking and spatiotemporal integration is used to model the motion‐induced profile of an edge moving on a scanning‐backlight LCD‐TV panel that exhibits the two drawbacks mentioned above. The model results are validated with a perception experiment including different refresh rates, and a high correspondence is found between the simulated apparent edge and the one that is perceived during actual motion. Apart from the motion‐induced edge blur, the perception of a moving line or square‐wave grating can also be predicted by the same method starting from the temporal impulse and frame‐sequential response curves, respectively. Motion‐induced image degradation is evaluated for both a scanning‐ and continuous‐backlight mode based on three different characteristics: edge blur, line spreading, and modulation depth of square‐wave grating. The results indicate that the scanning‐backlight mode results in better motion performance.

Digital Predictive Valley Current Control of Fourth Order Boost Converter under Trailing Edge Modulation

In this paper, a digital predictive valley current control is proposed for the 4th order boost converter. Detailed mathematical models of the converter system are formulated and then predictive average, peak and valley current control laws, in terms of valley current, are derived. Stability analysis of average, peak and valley current control, under trailing-edge modulation is carried out in the discrete domain. These investigations show that the average and peak current control schemes, with trailing edge-modulation, are unstable for certain duty ratio's, while the valley current control scheme is stable for all duty ratio's, 0 < D < 1. These theoretical studies are validated through the time-domain simulation studies. Discrete compensator is designed using digital direct design approach in order to realize the load voltage regulation together with the valley current control. Closed-loop performance of the proposed control scheme is simulated for different operating conditions. Experimental results are provided to validate the simulation results and theoritical stability predictions.

Power Supply Rejection for RF Amplifiers: Theory and Measurements

Supply noise is a significant problem in RF systems where it can mix with RF signals, degrading signal/noise ratios and potentially causing violation of spectral masks. This paper presents an analysis of the supply rejection properties of RF amplifiers. We extend a conventional Volterra-series formulation to treat multiport systems and use it to describe the mixing products between power supply noise and the RF carrier. It is shown that a multiport Volterra formulation can be used to treat weak nonlinearities in the system and that the nonsymmetric cross terms accurately predict low-order mixing phenomenon. We demonstrate the validity of our hand analysis through the design and fabrication of a power amplifier in 180-nm CMOS, operating between 900 MHz-2.4 GHz with a maximum output power of 15 dBm. Spectral regrowth of single-tone and EDGE modulation waveforms is shown to match within 1-3 dB across frequency and input signal power. Importantly, this analysis provides insight into the circuit-level mechanisms for susceptibility to power supply noise and can help designers improve the power supply rejection ratio robustness of system-on-chip wireless blocks and transmitter architectures.

A Single-Pair Serial Link for Mobile Displays With Clock Edge Modulation Scheme

A low-power, single-channel clock-edge modulated serial link has been fabricated in a standard 0.18-mum CMOS technology. The link core size is 343 times 188 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for the transmitter and 173 times 83 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for the receiver. The link consumes 3.12 mW when operating at 270 Mb/s with a 1.2-V supply. The proposed link transfers all necessary signals between a graphic processor and a mobile display device over a single pair channel, thereby greatly saving the power and cost of the existing full swing parallel lines. The proposed clock edge modulation (CEM) encoding can keep the channel DC-balanced without an additional bit overhead. Since a clock edge is present for each bit, an external reference clock is not needed and its operating frequency can be varied without the possibility of harmonic locking typically found in a referenceless clock and data recovery circuit. A simple DLL-based CEM decoder is described that recovers the data with low power consumption and high jitter tolerance. An analysis of the jitter tolerance to sinusoidal jitter is included along with measured data. The measurement results show jitter tolerance of 20 UI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-P</sub> with 1-MHz sinusoidal jitter. The use of a push-pull voltage-mode driver further reduces the power consumption.

Readout of Optical Disk Recorded by Pit Edge and Depth Modulation

We report a Read-only (ROM) disc which is recorded by pit edge and depth modulation (PEDM). The information recorded by pit edge modulation is read out through an RF signal channel, and that recorded by pit depth modulation is read out through a tangential push-pull signal channel by detecting signal polarity at the pit edge. Each signal is sliced with a single level and is combined with another signal so that a multi-value recording is realized without multiple level slicing. The information recorded and read out using tangential push-pull signal polarity can never be copied onto recordable discs. Thus, not only a larger recording density and a higher transfer rate but also secure information storage are achieved with no change of the current optical and mechanical systems.

A new modulation strategy for a buck-boost input AC/DC converter

This paper presents a novel modulation strategy for a power factor corrected (PFC), isolated AC/DC converter derived from the integration of a nonisolated, two switch buck-boost AC/DC converter with an isolated dual active bridge DC/DC converter (2SBBDAB). This strategy, termed discontinuous leading/trailing edge (DLTE) modulation, serves to maximize the duty cycle of the input switch while keeping the current in the buck-boost inductor discontinuous. Hence, the crest factors of the currents in the switching devices are minimized, the input switch is turned on at zero current and the zero-voltage switching ranges of the bridge switches are unaffected by the integration. A conventional isolated, PFC AC/DC converter typically consists of a boost converter cascaded with a forward converter. The ratings required of the power switching devices of the 2SBBDAB employing the DLTE modulation strategy are similar to those required of the conventional design for wide line voltage operation. However, the 2SBBDAB converter has higher line voltage surge immunity than that of the conventional design and, unlike the conventional design, it has inherent inrush current limiting. The DLTE modulation strategy may be applied to the family of converters composed of the two switch buck-boost integrated with half and full-bridge forward converters.

Across-object Relationships in Perceived Object Orientation

An orientation discrimination paradigm was used to determine whether the perceived orientation of extended objects is based on the distribution of edge-orientations or on the response of mechanisms that encode relationships across the object; specifically we considered large, second-stage filters and cores (the perceived middle of the object) as encoders of the across-object relationship. The stimuli were “rectangles” with sinusoidally modulated long edges. Manipulating the frequency and relative phase of the edge modulation allowed us to assess the importance of the across-object relationships. Evidence was found for the importance of such relationships in determining perceived orientation. No evidence was found for direct use of the distribution of responding edge detectors. Published by Elsevier Science Ltd.

A NOVEL RANDOM SWITCHING TECHNIQUE FOR HIGH PERFORMANCE INVERTER CONTROL

ABSTRACT A novel random switching technique for high performance inverter control is presented in this paper. Since the switches of power devices are randomized, the acoustic noise generated by the voltage and current harmonics of inverter control can be significantly reduced. It will also be shown that the technique has been developed without changing the sampling and modulation schemes, Asymmetric Regular-Sampling and double edge modulation schemes respectively, which have been widely used in practical inverter control systems. Therefore, the modifications necessary to upgrade the performance of inverters using the proposed random switching technique can be easily incorporated into existing digitalized inverter control systems, e.g. vector control systems. Furthermore, in comparison with the conventional randomized pulse position technique [10] which may result in single edge modulation and thereby causes greater mean value of flux error for drive control, the proposed random switching technique provides less mean value of flux error due to double edge modulation. In comparison with conventional inverter control techniques based purely upon the Asymmetric Regular-Sampling technique, e.g. space vector modulation [17], which results in fixed voltage and current harmonic spectra and therefore generates annoyed acoustic noise, the proposed random switching technique can reduce this kind of noise by randomizing the switches. Once the switches are randomized, the first dominant harmonic which dominates the generation of acoustic noise can be dramatically reduced. A novel Random Space Vector Modulation (RSVM) technique will be presented based upon the novel random switching technique. The RSVM technique is realized using a Digital Signal Processor (DSP) and the experimental results will be shown to confirm the theoretical analysis.

Linking object boundaries at scale: a common mechanism for size and shape judgments

The area over which boundary information contributes to the determination of the center of an extended object was inferred from results of a bisection task. The object to be bisected was a rectangle with two long sinusoidally modulated sides, i.e. a wiggly rectangle. The spatial frequency and amplitude of the edge modulation were varied. Two object widths were tested. The modulation of the perceived center approximately equaled that of the edges at very low edge modulation frequencies and decreased in amplitude with increasing edge modulation frequency. The edge modulation had a greater modulating effect on the perceived center for the narrower object than for the wider object. This scaling with object width didn't follow perfect zoom invariance but was precisely matched by the scaling of the bisection threshold with width, strongly supporting the idea that the same mechanism determines both the location of the perceived center for these stimuli and its variance. We propose that this mechanism is the linking of object boundaries at a scale determined by the object width.

Blue shifts from doubly δ-doped heterostructures

A “Holy Grail” of optical communications and computing is the all-optical modulation of light; we present the results of a study of doubly doped quantum wells, which show that large blue shifts in the emission energies can be obtained with moderate laser pump powers using Al x Ga 1 − x As In y Ga 1 − y As heterostructures. The wide (about 50 nm) quantum wells are doped at the centre with Si and Be δ layers, separated by either 5 or 10 nm. The well and the band edge modulation within the wells therefore resemble those of bulk n-i-p-i structures. The photoluminescence spectra are dominated by broad band-to-band emission peaks, which exhibit a pronounced dependence on excitation power density. For a change in incident power of two orders of magnitude, the peak of the emission can shift by over 200 meV. Modelling of the confined states in these structures allows the emission to be assigned to spatially direct or indirect transitions.