Reply to comments on "Improving accuracy of intrinsic coercivity measurement for magnetically soft materials"

For original article by G. Hilton et al. see ibid., vol.41, no.8, p.2322-7, Aug. 2005. For comments by H.K. Lachowicz see ibid., vol.42, no.3, p.481, March 2006.     

Efficient angular spectrum decomposition of acoustic sources. II. Results

For pt.I see ibid., vol.40, no.3, p.238-49 (1993). Results of angular spectrum computations are presented for three applications: general decomposition, pressure field calculation, and modeling of pulse-echo measurements. Wherever possible, analytical (exact) results are used as reference for the decomposition results. This permits the accuracy of the angular spectrum decomposition to be evaluated for specific choices of M and N where M is the number of samples across the maximum characteristic length, d, of the source region and N is the total number of samples along each side of the source decomposition plane, and for both sampling techniques. Based on the results for the three applications, guidelines for choosing M and N are presented in a graphical format.     

Comments on “efficient angular spectrum decomposition ofacoustic sources-parts I and II”[and reply]

Problems with the angular spectrum analysis of a recent pair of papers (see ibid., vol. 40, p. 238-49, 1993 and vol. 40, p. 250-57, 1993)are described. An alternative numerically correct approach is described and is used to efficiently and accurately re-compute a result considered in the original papers. The original authors give their reply to the comments     

Target velocity estimation with FM and PW echo ranging Doppler systems. II. Systems analysis

For part I see ibid., vol.40, no.4, pp.366-372 (1993). In Part I, the encoding of the velocity and range information into the received and demodulated signals based on transmission of coherent repetitive linear sweep signals, was discussed. In the present work, two different implementations of FM Doppler systems that can be used to obtain velocity profiles are presented. The first implementation is similar to the implementation of a conventional pulsed wave (PW) Doppler system, based on measurement of phase shift (correlation based system): the second implementation is a frequency-domain analog to the PW Doppler system, based on time shift measurements (cross correlation-based system).     

Comments on "A novel wide-band differential amplifier"

The circuit proposed by Khan and Arun Kumar in ibid, vol. 41, p.555-559 (Aug. 1992) has been originally proposed by Soliman and Ismail (see IEEE Trans. Circuits Syst., vol.CAS-26, p.112-117, 1979), who have derived the condition for minimum phase error, taking into account the single-pole model of the OA. The effect of second pole on this actively compensated finite gain amplifier has been analyzed by the author (see AEU, vol.42, p.192-194, 1988), wherein this circuit has been completely compared with other state of the art realizations regarding (a) gain error, b) phase error, (c) conditions required for minimizing phase error and gain error, (d) matching of active devices whether required, and (e) condition for stability taking into account the second pole of the opamp.<>     

Comments on "Frequency shifts in a resonator due to submersion in a fluid"

A critical analysis of the paper by Yang (see ibid., vol.53, no.3, p.662, 2006) is presented. The results presented in the paper are correct. Still, it is necessary to point out a few shortcomings that are possibly due to the fact that the author was not aware of some earlier papers when he submitted his paper     

REPLY - CONCERNING THE COMMENTS ON 'EFFICIENT EVOLUTIONARY STRATEGY OPTIMISATION PROCEDURE TO SOLVE THE NONCONVEX ECONOMIC DISPATCH ROBLEM WITH GENERATOR CONSTRAINTS'

For comments by A. Immanuel Selvakumar and Thanushkodi see ibid., vol.1, no.2, p.364-66, Jan. 2007     

Hardware implementation of a new phase measurement algorithm

A hardware implementation of the phase measurement algorithm developed by S.M. Mahmud (see ibid., vol.38, p.6-9, Feb. 1989) is presented. The proposed circuit was built and tested. The circuit can automatically adapt itself over a wide frequency range of the input wave     

Comments, with reply, on `Effect of various dither forms oquantization errors of ideal A/D converters' by M.F. Wagdy

In the above-titled paper (see ibid., vol.38, p.850-5, Aug. 1989), the effect of dithering on correlation (covariance) between the signal and the quantization error and on the spectrum of quantization errors was addressed. The commenter shows that for the evaluation of the correlation (or covariance) more effective methods exist, and the covariance between the signal and the quantization error can be easily made equal to zero with appropriate dithering. It is also pointed out that the mean value of the signal must be taken into account. Some misunderstandable statements on the error spectrum are stated precisely. The author replies that the commenter misunderstood the original paper and further amplifies his work in support of this assertion     

Comments on “Electron and Hole Current Characteristics of n-i-p-Type Semiconductor Quantum Dot Transistor”

It is pointed out that all of the four integrals used in Fujihashi et al. (see ibid., vol.6, no.3, p.320, 2007) can be reduced to closed forms involving elementary expressions.     

Comment on "Nanorobotics control design: a collective behavior approach for medicine"

Following the paper by Calcavani and Freitas (see ibid., vol.4, no.2, p.133-40, 2005), the limitations on nanorobot design and activity imposed by Brownian motion events, communication problems, and the nature of the intercellular space are discussed. It is shown that severe problems exist for a nanorobot designed to enter tissues for therapeutic purposes when it is smaller than about 1 /spl mu/m in any one of its dimensions.     

Linearizing average transfer characteristics of ideal ADC's viaanalog and digital dither

This paper is a continuation to the previous work by M.F. Wagdy (see ibid., vol. 38, p. 850-855, Aug. 1989). It further investigates the effect of various dither forms, i.e., with different probability density functions (PDF's), on the average observed transfer characteristics of ideal A/D converters (ADC's). First the deviation of the ADC characteristics from the ideal straight line is evaluated for analog dither forms using the concept of nonlinearity spectra developed in the above work. Second, two cases of digital (discrete) dither are investigated, one with rectangular envelope and the other with triangular one. Effects of dither peak-to-peak values and number of PDF impulses are investigated. The paper provides a quantitative basis for replacing analog dither with the easier to implement digital dither     

A real-time ultrasound time-domain correlation blood flowmeter. II. Performance and experimental verification

For Part I, see ibid., vol.40, no.6, p.768-775 (1993). The performance of a real-time ultrasound time-domain correlation (UTDC) flowmeter employing a high-speed residue number system correlator under various flow conditions for different correlation parameter settings is evaluated. Previous work has incorporated a weighted-averaging scheme to estimate the flow velocity over a wide number of echo signal spacings. The present evaluation indicates that a linear averaging of 50 adjacent echo signal pairs produces equivalent accuracy and precision at real-time processing speed as compared to previous non-real time systems incorporating weighted averaging.     

Wavefront amplitude distortion and image sidelobe levels. II. In vivo experiments

For part I, see ibid., vol.40, no.6, p.747-753 (1993). In vivo measurements of the rise of the sidelobe level in a single-source image obtained through the female breast as a function of the distortion of the wavefront amplitude are described. The measured sidelobe levels are the average sidelobe floor (ASF) and the peak sidelobe level (PSL). The ASF is shown to be proportional to the variance of the modulus of the wavefront normalized to the square of its mean value, with a proportionality constant close to the value predicted by theory. The PSL similarly increases linearly. The average ratio of PSL to ASF is 5 (7 dB).     

Comments to `Perfect and imperfect particles' by A. Aharoni

For original paper see ibid., vol.22, p.478-83 (Sept. 1986). The present author comments on criticisms made by A. Aharoni of some aspects of the present author's. It is not doubted that Aharoni's work gives exact results for the nucleation field (but the coercivity is of prime interest) for some `perfect' geometries. Real particles depart very markedly from these idealized forms having, e.g. blunt ends, pores, irregular shape, and an easy axis for the magnetocrystalline anisotropy which is not coincident with the axis of the particle and these solutions may not then apply. In this situation it appears to the present author that it is legitimate to look for approximate solutions better suited to more realistic models     

CFCs, ozone depletion, and their impact on the electronicsindustry. II. The way ahead

For pt.I see ibid., vol.1, no.3, p.131-41, 1992. The second part of this paper provides an insight into the consequential severe problems facing the electronics industry (particularly with regard to defluxing printed circuit boards and cleaning precision parts) and the options available to it. In addition, both the short-term and the long-term collaborative actions being undertaken world-wide to assess and implement the nonCFC cleaning regimes are outlined     

Synthetic receive aperture imaging with phase correction for motion and for tissue inhomogeneities. II. Effects of and correction for motion

For Pt.I see ibid., vol.39, p.489 (1992). The effects of tissue/transducer motion and artifacts from adaptive focusing on synthetic receive aperture (SRA) imaging are explored using experiment, simulation, and theory. The impact of these issues on the selection of SRA subaperture geometry is discussed, and a technique to address this problem is demonstrated. The results indicate that SRA with phase correction holds promise in improving ultrasonic image quality.     

Modified nodal analysis and the incorporation of multiphase, coupled networks

As a note to an original presentation ("Modified nodal analysis: an essential addition to electrical circuit theory and analysis", see ibid., vol.11, no.3, p.84-92, 2002), this paper adds a further, final comment on the efficacy of modified nodal analysis (MNA) in handling multi-phase, coupled impedance networks typical of which are multi-conductor transmission lines and cables in which the electrical length is short so that the network elements are discrete lumped impedances.     

Comments, with reply, on `A digital frequency independentphasemeter' by A. Nemat

The commenters point out that the phase-measurement scheme presented in the above-titled paper by A. Nemat (see ibid., vol.39, p.665-7, Aug. 1990) is essentially the same as that previously presented by the commenters (Proc. IEEE, vol.72, p.397-8, Mar. 1984). In fact, it is suggested that the former scheme is a special case of the latter one when the counting time interval τ is equal to the time period T _s of the signals. In reply, Nemat agrees that his scheme can be regarded as another approach to achieving the same goal. He goes on to point out some differences between his approach and that of the commenters     

Parameter estimation in strongly nonlinear circuits

The combination of the generalized Volterra approach to compute the steady-state output of strongly nonlinear systems with the maximum likelihood estimator (MLE) developed by J. Schoukens et al. (see ibid., vol.IM-37, p.10-17, 1988) yields a powerful tool to estimate the parameters in strongly nonlinear circuits. As a result, it is possible to determine system characteristics that cannot be measured directly or are difficult to obtain. The latter is illustrated by means of an inverting amplifier built around an operational amplifier causing slew-induced distortion. Two different models are used to represent the operational amplifier. The first considers only one nonlinearity, namely a saturating current source characterized by two parameters, but can only describe symmetric slew-induced distortion. The other model uses two diodes and results in a six-parameter model capable of addressing the asymmetric case. By comparing the results obtained for these approaches with measurements on the actual circuit, the capability of the identification technique for strongly nonlinear systems is demonstrated