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Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 16, Issue 12, 5 June 1980

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Volume 16, Issue 12

5 June 1980

Velocity, electromechanical coupling factor and acoustic loss of surface shear waves propagating along x-axis on rotated Y-cut plates of LiNbO3
  • Author(s): Hiroomi Kojima ; Yasuaki Kinoshita ; Mitsuaki Hikita ; Toyoji Tabuchi
  • Source: Electronics Letters, Volume 16, Issue 12, p. 445 –446
  • DOI:  10.1049/el:19800313
  • Type: Article
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  • p. 445 –446 (2)
    Velocity and propagation loss of surface shear waves are measured on free-space and metallised surfaces of LiNbO3 crystals along the x-axis of rotated Y-cut plates as a function of rotation about the x-axis between 35° and 70°. The coupling factor obtained from the velocities is 0.20 for a 35° rotated Y-cut plate and 0.09 for a 70° plate. The coupling factor changes linearly with the rotation angle. The propagation losses over the whole range measured here are less than 5 dB/cm on both free-space and on metallised surfaces. These losses are fairly low and very favourable for fabricating s.a.w. filters.
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Resonant s.a.w. filter using surface shear wave mode on LiTaO3 substrate
Filters using digital techniques to improve operation of a fast digital phasemeter
Frequency dependence of effective path length in prediction of rain attenuation statistics
Subjective assessment method for television digital codecs
Terminations for magnetostatic waves
Moment-method solution of directed dipole antennas
1.5–1.6 μm GaInAsP/InP Integrated twin-guide lasers with first-order distributed Bragg reflectors
Single-mode oscillation under high-speed direct modulation in GaInAsP/InP integrated twin-guide lasers with distributed Bragg reflectors
  • Author(s): Y. Sakakibara ; K. Furuya ; K. Utaka ; Y. Suematsu
  • Source: Electronics Letters, Volume 16, Issue 12, p. 456 –458
  • DOI:  10.1049/el:19800321
  • Type: Article
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  • p. 456 –458 (3)
    Spectral behaviour of 1.3 μm GaInAsP/InP integrated twin-guide lasers with first-order distributed Bragg reflectors under high-speed direct modulation was measured. It was confirmed that stable single-longitudinal-mode operation is maintained for applied modulating current pulse width of only 1 ns. The rise time and width of the light output pulse were less than 0.3 and 3 ns, respectively.
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7B8B balanced code with simple error detecting capability
Relationship between power added efficiency and gate-drain avalanche in GaAs m.e.s.f.e.t.s
Sampling theorem application to s.a.w. diffraction simulation
Inclusion of amplifier finite gain and bandwidth in analysis of switched-capacitor filters
Simple self-centring technique for mounting microsphere coupling lens on a fibre
Estimating the pitch period of voiced speech
  • Author(s): E. Ambikairajah ; M.J. Carey ; G. Tattersall
  • Source: Electronics Letters, Volume 16, Issue 12, p. 464 –466
  • DOI:  10.1049/el:19800327
  • Type: Article
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  • p. 464 –466 (3)
    In speech processing an estimation of the speech pitch period is important. Real time pitch detection is only possible by the selection of an efficient algorithm suitable for implementation on a programmable processor or in special-purpose hardware. The use of the periodogram algorithm (p.a.) is proposed to detect the pitch period of voiced speech. This algorithm is attractive for the following reasons: (a) it has no multiply operation; (b) when implemented on a 16-bit computer (e.g. microprocessor) the computation can be done in integer arithmetic without exceeding the microprocessor's dynamic range; (c) it is a simple technique for estimating the pitch period with reasonable accuracy. Results of the analysis of speech signals and sinusoids using the periodogram algorithm are presented and comparisons are made with the average magnitude difference function (a.m.d.f.) which is an alternative method of estimating the pitch period of the voiced speech.
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Practical realisation of mod p, p prime multiplier
Impact ionisation in multilayered heterojunction structures
  • Author(s): R. Chin ; N. Holonyak ; G.E. Stillman ; J.Y. Tang ; K. Hess
  • Source: Electronics Letters, Volume 16, Issue 12, p. 467 –469
  • DOI:  10.1049/el:19800329
  • Type: Article
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  • p. 467 –469 (3)
    Calculations are reported showing that in multilayered heterojunction structures the effective impact ionisation rates for electrons and holes can be very different, even if they are the same in the basic bulk materials. The reason for this is the difference in the band-edge discontinuities for electrons and holes and the lower phonon mean free path for holes in quantum well structures.
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Effect of deposition rate on spectral loss of GeO2-P2O5-SiO2 graded index fibres
Generation of surface acoustic waves by means of a c.w. laser
Parasitics-insensitive switched-capacitor ladder filters
Estimation of a sinusoid in uncorrelated noise using adaptive line enhancer
  • Author(s): V. Umapathi Reddy
  • Source: Electronics Letters, Volume 16, Issue 12, p. 473 –475
  • DOI:  10.1049/el:19800333
  • Type: Article
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  • p. 473 –475 (3)
    In applications of adaptive line enhancers (a.l.e.) for detecting sinusoidal signals in uncorrelated noise, an arbitrary value of delay Δ, the decorrelation parameter, is suggested and Δ = 1 is normally used. Exact analysis of the a.l.e. for the case of a single sinusoid in uncorrelated noise shows that an optimum value of Δ exists for which the a.l.e. yields much better estimate of the sinusoid frequency compared to that with Δ = 1. The simulation results show an excellent agreement with the predicted behaviour.
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Novel phase lead inverting integrator and its application in two-integrator loop filters
Short-channel polysilicon-gate m.o.s.f.e.t.s fabricated by c.w. argon laser annealing of arsenic-implanted source and drain
  • Author(s): T.C. Teng ; J.D. Merritt ; J. Velez ; J. Peng ; L. Palkuti
  • Source: Electronics Letters, Volume 16, Issue 12, p. 477 –478
  • DOI:  10.1049/el:19800335
  • Type: Article
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  • p. 477 –478 (2)
    Short-channel polysilicon-gate n-channel m.o.s.f.e.t.s have been successfully fabricated using c.w. argon laser annealing of arsenic-implanted source and drain. The turn-on voltage is higher for the laser annealed devices than for those annealed thermally, which were processed identically except for the source and drain annealing. Laser annealing also reduced the n+-layer sheet resistance to about half that of the thermally annealed n+ regions.
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Transmission characteristics of 116.3 km and 65.1 km graded-index v.a.d. fibres at 1.55 μm and 1.3 μm
  • Author(s): T. Edahiro ; M. Kawachi ; S. Sudo ; H. Nagai
  • Source: Electronics Letters, Volume 16, Issue 12, p. 478 –480
  • DOI:  10.1049/el:19800336
  • Type: Article
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  • p. 478 –480 (3)
    Seven long pieces of fibre with low loss and wide bandwidth properties made by the v.a.d. method were spliced with V-grooves into an 116.3 km graded-index fibre, and three long pieces of fibre into a 65.1 km fibre. Transmission characteristics of these graded-index fibres were measured with a swept-frequency method using InGaAsP/InP b.h. laser diodes operating at 1.55 μm (made by low temperature liquid-phase epitaxial growth) and 1.3 μm, respectively. The overall transmission losses and 6 dB down electrical bandwidths at the two wavelengths were 37 dB and 16.5 MHz, 35.2 dB and 36.5 MHz, respectively.
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Strays-insensitive active switched-capacitor biquad
Novel insensitive lossless inductor simulation through inverse function generation
  • Author(s): R. Nandi
  • Source: Electronics Letters, Volume 16, Issue 12, p. 481 –483
  • DOI:  10.1049/el:19800338
  • Type: Article
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  • p. 481 –483 (3)
    This communication describes a new method of active lossless single-element controlled inductor simulation by realising a function H = [1 − (Y2/Y1)]−1 with a negative impedance convertor block (n.i.c.) and then generating 1/H by an infinite-gain operational amplifier (o.a.). Suitable resistive feedback is then applied to synthesise Yin = Yo (1 − H−1) = Y0Y2/Y1 which yields a lossless inductor with Y1 = sC, Y0 = 1/R0 and Y2 = 1/R2. The lossless inductor is shown to be insensitive to active parameter changes with an appropriate choice of the active elements such as the n.i.c. implementation with a second generation current conveyor (c.c.II) and inverse generation by an o.a.
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Deep trapping centres in n-GaAs surface barrier diodes for nuclear radiation detection
  • Author(s): S.J. Pearton ; A.J. Tavendale ; A.A. Williams
  • Source: Electronics Letters, Volume 16, Issue 12, p. 483 –484
  • DOI:  10.1049/el:19800339
  • Type: Article
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  • p. 483 –484 (2)
    Deep level transient spectroscopy has been applied for the first time in the study of deep level trapping centres in n-GaAs nuclear radiation detectors. Devices from bulk and epitaxial material with net donor impurity densities from 5×1013 to 3×1016 cm−3 have been studied and several common levels observed. The Poole-Frenkel effect has been identified in three levels (Ev+0.19 eV, Ec−0.62 eV, Ec−0.73 eV) in the epitaxial GaAs. A value for the Poole-Frenkel constant of β = 4.7±1.4×10−4 eV V−½ cm½ was obtained for the Ec−0.62 eV level, compared to the theoretical value for GaAs, 2.3×10−4 eV V−1/2 cm1/2.
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Spiral antenna with integrated detector

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