Propagation Circuit Research Articles

Common Mode Noise Analysis for Inductive Power Transfer System Based on Distributed Stray Capacitance Model

This article reveals the significant stray capacitances in inductive power transfer (IPT) coil, and offers two methods for modeling the stray capacitance effect: concentrated model and distributed model. Both analytic formulas and FEM simulation are introduced to estimate the value of parasitic capacitances, and experimental measurements on an 11 kW IPT coil prototype are conducted to verify the correctness of both methods. The common-mode noise propagation circuit of the IPT system is derived and simulated based on these two models. The results show that parasitic capacitance between Litz wire winding and shielding metal on the transmitter side plays a dominant role in CM noise propagation and the distributed model has higher fidelity because of its asymmetric structure. Besides, to mitigate conductive CM noise, an EMI filter, and HF isolation transformer are introduced. Finally, the conductive EMI tests are performed in an 11kW IPT prototype. The experimental results validate the accuracy of the proposed CM noise model with stray capacitances of the IPT coil. And the combination of EMI filter and HF isolation transformer can suppress CM noise greatly and render the CM noise spectrum below the CISPR 32 Class-B limit.

Low-Power CMOS Synchronous Counter With Clock Gating Embedded Into Carry Propagation

A novel low-power CMOS synchronous counter whose clock-gating logic is embedded into a carry propagation circuit is proposed. The proposed synchronous counter operates with no redundant transitions and requires fewer transistors, minimizing the switching power consumption and silicon area as compared with conventional CMOS synchronous counters. The proposed synchronous counter consisting of 16 bits was fabricated in 0.18-mum CMOS technology. The experimental result indicates that the proposed synchronous counter achieves a power saving of 64% with 15% device count reduction.

Time-varying propagation circuits, description and applications

In radio/radar observations of natural targets, such as planets, satellites, asteroids and comets, the Earth's surface or the ionosphere, the troposphere and the stratosphere the response of the target to a signal can often be thought of as the response of a time-varying circuit. In recent investigations of the mesosphere, troposphere and stratosphere the measurement of the coherence between returns obtained in response to gated sine wave transmissions at adjacent frequencies has been used to increase the range resolution. In atmospheric radar applications this procedure has been referred to as frequency domain interferometry. The frequency correlation concept was previously introduced into radar astronomy, and was worked into the general concept of description of a time varying random propagation circuit. In such a circuit the properties can be described by a function of two parameters, the time delay τ and the frequency offset from the transmitter frequency Δ f. Integrating the function over frequency offsets one obtains the square of the mean impulse response as a function of delay, and integrating over all time delays one relating to the power spectrum of the circuit time variation irrespective of time delay. The time delay and frequency pair, ( τ,Δ f), can be used for the circuit description, but there are three more ways of describing the circuit in statistical terms, two of them involving the frequency separation Δ f as in frequency-domain interferometry. The different statistical descriptions and their interrelations are explained. Methods are indicated whereby estimates of the different statistical parameters of the circuit can be determined. In some cases the statistical properties may be definite functions of the pair of parameters, and in such cases special methods may be devised to derive the circuit properties and optimize detectability.

Analytic calculation of the ordinary (O) and extraordinary (X) mode nose frequencies on oblique ionograms

On oblique ionograms, the maximum frequencies of the ordinary and extraordinary modes are referred to as nose frequencies. The difference in the nose frequencies depends on parameters such as the length of the propagation circuit and the direction of propagation. In this paper, the difference in nose frequencies is studied using the frequency scaling technique of Bennett et at. [(1991) Appl. Comput. Electromagn. Soc. Jl 6, 192]. For long paths, an explicit formula is obtained which gives the difference approximately as a function of the local magnetic dip and azimuth of propagation at the ray mid point. For shorter paths, it is shown how analytic ray tracing can be used to determine the difference.

A 1.5-ns 32-b CMOS ALU in double pass-transistor logic

Describes circuit techniques for fabricating a high-speed adder using pass-transistor logic. Double pass-transistor logic (DPL) is shown to improve circuit performance at reduced supply voltage. Its symmetrical arrangement and double-transmission characteristics improve the gate speed without increasing the input capacitance. A carry propagation circuit technique called conditional carry selection (CCS) is shown to resolve the problem of series-connected pass transistors in the carry propagation path. By combining these techniques, the addition time of a 32-b ALU can be reduced by 30% from that of an ordinary CMOS ALU. A 32-b ALU test chip is fabricated in 0.25- mu m CMOS technology using these circuit techniques and is capable of an addition time of 1.5 ns at a supply voltage of 2.5 V.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Propagation and circuit characteristics of inductively coupled superconducting microstrip

The propagation characteristics and circuit properties of two inductively coupled superconducting transmission lines are studied. An expression for the attenuation of the coupled-line modes is derived for the case of low loss. It is found that for transmission line geometries of practical interest the low-loss expression agrees well with the more general numerical solution. The numerical solution is used to determine the dispersion characteristics of inductively coupled lines as a function of the superconductor thickness and the operating temperature. An equivalent circuit, with the same dispersion equation, is presented along with the relationship between the circuit element values and the physical parameters of the line. The characteristic impedances of the two dominant coupled-line modes are derived from the equivalent circuit expressions. >

Hi‐bicmos 32‐bit execution unit

AbstractThe applicability of the Hi‐BiCMOS (High Performance Bipolar CMOS) technology to the 32‐bit execution unit has been researched to improve the function and speed of such processors as minicomputers CPUs. The HiBiCMOS technology enables MOS devices with performance comparable to pure CMOS LSIs and bipolar devices with performance comparable to pure bipolar LSIs to be combined on the same substrate. Device integrations comparable to CMOS LSIs have been achieved by the utilization of macrocells composed mainly of MOS circuits. Attempts have been made to speed‐up the macrocells by adding Hi‐BiCMOS circuits.In this paper, the feedback‐type smallamplitude precharge circuit is proposed and fabricated. This circuit affords precise bus voltage. Also, the carry propagation circuit that uses the bipolar sense amplifier to achieve the machine cycle of 25 ns is proposed. Consequently it is confirmed that the precharge circuit operates two times faster and the carry propagation circuit 3.3 times faster than pure CMOS circuits. Thus, one of the promising candidates for the ultrahigh‐speed one‐chip processors is shown.

低温焼成ガラス・セラミック基板 高速伝送，高密度実装基板

低温焼成ガラス・セラミック基板 高速伝送，高密度実装基板

Computer simulation of the operation of a magnetic bubble domain propagation circuit modeled after a current-access device

The operation of a bubble-domain straight-line propagation circuit has been simulated successfully. This simulation has been achieved by our approximating the motion of an s = 0 frozen-azimuth bubble placed under a drive field H_{Z}(X, Y, T)= -H_{p} \cdot \cos [2\pi(X/R_{X} - n(T)/4)] \cdot \exp [-(Y/R_{Y})^{2}] . The simulation has been generated from a previously developed numerical scheme to simulate the motion of a bubble, whose domain shape and magnetization structure along its domain wall were variable. The drive field has been modeled after a dual conductor-sheet, current-access propagation structure, which has a bit period R X and a transverse width on the order of 2R_{Y} . The entire field contour has been advanced stepwise in the positive X direction by an increase of the integer n(T) , which represents the drive-phase number. The bubble motion has been observed during the first six drive phases to produce operating margin diagrams for drive frequencies of 250 KHz, 796 KHz and 1 MHz. The method of calculation and the results of the simulation are given.

Magnetic bubble propagation for the dual conductor current-access test circuit

In this paper, the design and propagation results for the dual conductor current-access test circuit are presented. Bias margins as large as 10 Oe were obtained at 500 KHz for the straight line propagation circuit (propagation normal to the drive currents), the structure period being 12 μm. At 900 kHz also, propagation was observed. A (Y, Sm, Lu, Ca) 3 (Fe, Ge) 5 O 12 garnet film was used and the bubble diameter of this material was 3.3 μm.

Novel permalloy gapless propagation circuit

A novel, gapless single-Permalloy, propagation circuit for field access bubble memories has been developed which has a period-to-minimum-feature ratio of 5:1 and a similar packing density to that of C or chevron elements. The circuit consists of gapless chevron-like elements with magnetic lock between them to prevent domain oscillation. Instead of gaps, the minimum feature is the smallest width of the structure, which might be about the diameter of a bubble. The results show low minimum drive field requirement of the structure and a typical short-term propagation margin of at least 15% of the bias field under normal operating conditions.

The optimum design of magnetic bubble propagation circuits

This paper describes a procedure for the optimal design of field access bubble propagation circuits. Each type of propagation circuit is described by the assignment of a set of parameters. An objective function of these parameters is formulated to describe the ideal to be achieved. An optimization procedure is applied to the objective to compute the set of optimum parameters. Various objectives can be used, one such is: maximizing the speed of the device by maximizing the propagating potential-well gradients, and minimizing bubble size fluctuations by adjusting the potential-well profile. The optimization package used permits the application of constraints on the circuit parameters such as the assuring of propagation past critical points in the circuit and limiting the parameters to realistic ranges. An example is given to show the results of optimizing the performance of a T-I propagation circuit.

The corrugated reflector model for one-hop oblique propagation

The corrugated reflector model for simulating the effect of Travelling Ionospheric Disturbances is cast in a form enabling the compilation of families of curves for comparison with experimental observations. The expected Doppler, azimuthal and elevation variations in the received signal on a one-hop propagation circuit are discussed. Much information concerning the TID can be inferred from observations at a single receiving station.

Developments in magnetic bubble memories

Two new developments for magnetic bubble memories, a bubble propagation circuit and a bubble detector, are presented. The propagation circuit uses a channel with periodic traps coupled with asymmetrically placed bars of soft magnetic material to propagate bubbles nondirectionally with an alternating transverse magnetic field. This structure lends itself to very compact corners and transfer gates used in bubble memories with operating margins virtually identical to those of the straight line propagation circuit. A major-minor loop memory structure based on the channel-bar propagator is discussed. The structure yields independent propagation in the assembly and the storage loops using two mutually perpendicular transverse magnetic fields. The active bubble detector designed to match the excellent properties of the above circuit and to provide a means of nondestructive read-out is also discussed. The detector is based on a magneto-elastic phenomenon and does not require any electric current to operate.

Control function margin degradation in a bubble memory chip

Chip control function and propagation circuit margin degradation due to long-term memory operation, was observed, using the bias field switching technique. 16 kbit major-minor loop organized bubble memory chips with 28 μm bit period, which had an average access time of 2.7 ms for a 100-kHz rotating field, were used. It was seen that degradations in the lower side of the bias field range were independent of chip functional elements. However, at the upper side of the bias field range, degradations in the performance can be classified by dividing the elements into two categories. These were propagation circuits (Permalloy patterns only) such as H-bars, chevrons, etc., and control functions (Permalloy and conductor patterns), such as generators, replicators, etc. Also, it was found that the degradation in the performance of propagation circuits is small compared with that of the control functions. These differences were considered to be caused by a failure in the Permalloy steps over conductors and/or by the magnetic interaction of the bubble and the conductor current.

Dynamics of normal magnetic bubble domains in propagation circuit

Dynamics of normal magnetic bubble domains in propagation circuit

Dynamic conversion of magnetic bubble domain walls at megahertz frequencies in epitaxial garnet films

We have measured the circuit propagation characteristics of magnetic bubble domains in 15 different epitaxial films of Y1.9Sm0.1Ca1Ge1Fe4O12, using a TX propagation circuit with 28.8−μm period. For film thicknesses of 2 μm or less, reliable propagation was observed up to 1.7 MHz. Thicker films ceased to propagate reliably at frequencies as low as 0.5 MHz. Propagation failure is attributed to dynamic conversion of the bubble domain walls, and reasonably good quantitative agreement is shown between our measured critical frequencies and the critical frequencies calculated from a recently published model for dynamic conversion.

An experimental investigation of potential wells and drive fields in bubble domain circuits

The effect of an in-plane field on the diameter of a bubble located under a permalloy element can be used to measure the potential wells and drive fields of a propagation circuit. The wells decrease in depth with increasing separation between the garnet film and permalloy element, but increase in depth with increasing in-plane fields. The wide variation in well depth with element geometry accounts for the previously observed uneven motion along propagation tracks. Changes in the operating margins for bubble propagation have been studied as a function of the silica spacing thickness, and can be qualitatively understood by reference to the potential well behaviour. A method is described for determining material mobilities of the garnet films from a knowledge of (a) the potential wells under stable locations, and (b) time-of-flight measurements between those positions.

Conductor propagation circuits for high-density bubble- domain memories

Garnet epitaxial wafers are now available [1,2] which permit data to be stored at densities greater than one million bits per square inch (>200 000/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and which allow data to be shifted at rates greater than one megahertz. We are developing circuits to fully utilize these materials which will be directly compatible with integrated-circuit peripherial electronics. They contain a number of independent storage loops, typically 512 bits, which are randomly accessible. Data is read by propagating the domain stream past a magnetoresistance domain detector element when the peripheral electronics applies a series of bipolar pulses (typically 2 volts and 8 mA) to the single-conductor propagation circuit of the loop to be read. The propagation circuit consists of a pattern of serrated-edge grooves etched into the epitaxial garnet layer [3,4] and overlapped with a serpentine conductor [5]. Information has been coded onto a complete stream of domains (one per bit) by using the lateral displacement technique [6]. Memory chips of the type described here are easily designed into small or large systems since the only external mechanical requirements are a constant magnetic bias field (supplied by a permanent magnet) and a reasonable amount of shielding from stray magnetic fields.

Negative Sudden Phase Anomaly

IT sometimes happens that even when the flux from a soft X-ray flare on the Sun is sufficient to ionize the neutral constituents of the Earth's atmosphere at the level where very low frequency (VLF) radio waves are reflected, no sudden phase anomaly is observed on VLF propagation circuits that are in the sunlit hemisphere of the Earth, or are in a daytime condition even though part of the circuit is in darkness1,2. This is referred to as a “no SPA effect” or “null SPA effect”. I have explained1,2 the null effect in terms of waveguide theory using the exponential ionospheric model3 and I concluded that the null effect would occur when the enhancement of the intensity of the solar soft X-ray flux is small and moreover when the representative solar zenith angle on the VLF propagation circuit is large. At that time I predicted the existence of “negative SPAs” when the conditions that give rise to the null effect are strongly developed2.