Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887
banner image
image of Volume 13, Issue 19
Online ISSN 1350-911X Print ISSN 0013-5194

Electronics Letters

Volume 13, Issue 19, 15 September 1977

Volumes & issues:

Volume 13, Issue 19

15 September 1977

Calculation of forward scatter and crosspolarisation from ice spheroids
  • Author(s): P.A. Watson  and  A.W. Dissanayake
  • Source: Electronics Letters, Volume 13, Issue 19, p. 555 –556
  • DOI:  10.1049/el:19770398
  • Type: Article
  • + Show details - Hide details
  • p. 555 –556 (2)
    Forward-scatter complex amplitudes for ice particles with the same eccentricities as raindrops are presented from a field point-matching calculation to a greater accuracy than in a previous letter. However, it is noted that significantly higher crosspolarisation is expected from small ice needles or plates. Arguments for the orientation of ice needles or plates in electric fields are emphasised.
    Add to favourites
    Export citations
Satellite-ground signal depolarisation at millimetre wavelengths through thunderstorms
  • Author(s): P.F. Shutie ; E.C. Mackenzie ; J.E. Allnutt
  • Source: Electronics Letters, Volume 13, Issue 19, p. 556 –558
  • DOI:  10.1049/el:19770399
  • Type: Article
  • + Show details - Hide details
  • p. 556 –558 (3)
    Measurements are reported of 30 GHz signal fading and depolarisation occurring on a satellite-ground link during a period of severe thunderstorm activity. Simultaneous observations of the storms using both a p.p.i. and a fixed-beam radar provide further evidence of the severe depolarisation caused by hydrometeors above the freezing layer, and evidence is presented of abrupt changes in the level of depolarisation, which are associated with lightning strokes.
    Add to favourites
    Export citations
Electrical properties of thermal oxides on GaAs
Coupled slot waveguide s.a.w. resonators
  • Author(s): L.A. Coldren
  • Source: Electronics Letters, Volume 13, Issue 19, p. 559 –561
  • DOI:  10.1049/el:19770401
  • Type: Article
  • + Show details - Hide details
  • p. 559 –561 (3)
    Grooved-grating, waveguided s.a.w. resonators are coupled by the evanescent fields of single-mode slot waveguides formed by layers of MgO on SiO2 substrates. Except for higher out-of-band levels, the transfer characteristics of these devices compare favourably with alternative monolithically coupled s.a.w.-resonator geometries. A 4-pole response with a 3 dB bandwidth < 20 kHz and insertion loss < 6 dB is illustrated at 131.5 MHz.
    Add to favourites
    Export citations
Novel microstrip bandstop filter
Model for the effect of electric fields on satellite-Earth microwave radio propagation
Design tables for a class of data-transmission filters
Equal-valued grounded-capacitor active RC realisation of all-pole transfer functions
Variation of canting-angle distribution as a function of wind velocity
Numerical holographic reconstruction by a ‘projective transform’
  • Author(s): A.K. Booer ; J. Chambers ; I.M. Mason
  • Source: Electronics Letters, Volume 13, Issue 19, p. 569 –570
  • DOI:  10.1049/el:19770407
  • Type: Article
  • + Show details - Hide details
  • p. 569 –570 (2)
    A numerical method of holographic reconstruction of 2-dimensional fields is presented. Reconstructions are obtained indirectly, by generating the 2-dimensional Fourier transform of the field by using the slowness curve of the medium. Wideband data can be handled efficiently by this method, which also works in dispersive and anisotropic space. Examples of monochromatic and multifrequency holographic reconstructions are shown.
    Add to favourites
    Export citations
Experimental verification of the electromagnetic analogue of a theorem due to Dean
Effect of squall-line direction on space-diversity improvement obtainable with millimetre-wave satellite radiocommunication systems
  • Author(s): E.C. MacKenzie  and  J.E. Allnutt
  • Source: Electronics Letters, Volume 13, Issue 19, p. 571 –573
  • DOI:  10.1049/el:19770409
  • Type: Article
  • + Show details - Hide details
  • p. 571 –573 (3)
    The relative movement of intense rain cells associated with a squall line significantly affects the improvement obtained by any given pair of earth stations operating In space diversity. The letter outlines an experiment for observing the movement of rain cells across a 30 GHz space-diversity network using a p.p.i. radar, and presents in detail the analysis of a prefrontal squall event. Values of rain attenuation computed from the radar are compared with those measured on the 30 GHz network.
    Add to favourites
    Export citations
Runlength coding systems for black-and-white facsimile pictures: a comparison
Design of an active distributed RC lowpass network
  • Author(s): G.H. Tomlinson  and  L. Unsworth
  • Source: Electronics Letters, Volume 13, Issue 19, p. 575 –576
  • DOI:  10.1049/el:19770411
  • Type: Article
  • + Show details - Hide details
  • p. 575 –576 (2)
    The letter considers the design of an active distributed RC network to approximate to the magnitude characteristic of an all-pole lowpass filter transfer function. The limitations of the dominant-pole method are examined and it is shown that this method can lead to significant errors for filters with equiripple passband characteristics. A method is described and design curves are given to improve the approximation.
    Add to favourites
    Export citations
Tunable millimetre-wave ferrite bandpass filter with reduced biasing field
Hand-held tool for optical-fibre end preparation
Suppression of bulk-scattering loss at s.a.w.-resonator reflectors
  • Author(s): R.C.M. Li  and  J.A. ALUSOW
  • Source: Electronics Letters, Volume 13, Issue 19, p. 580 –581
  • DOI:  10.1049/el:19770414
  • Type: Article
  • + Show details - Hide details
  • p. 580 –581 (2)
    Tapering of the groove depth at the edges of grooved-array reflectors is shown to be effective in suppressing surface-to-bulk-wave conversion losses at such reflectors in an s.a.w. resonator. With such tapering, Q-factors of 80,000 at 174 MHz and 61,000 at 157 MHz have been measured on evacuated LiNbO3 and s.t.-quartz resonators, respectively. These measurements were made on ‘empty’ resonators having no transducers between the gratings. The latter value is within 3% of the best estimate of the material Q-factor of 63,000 at 157 MHz.
    Add to favourites
    Export citations
InP-Langmuir-film m.i.s. structures
Improved cavity-stabilised oscillator circuit for single-mode operation
  • Author(s): R. Knöchel  and  K. Schünemann
  • Source: Electronics Letters, Volume 13, Issue 19, p. 583 –585
  • DOI:  10.1049/el:19770416
  • Type: Article
  • + Show details - Hide details
  • p. 583 –585 (3)
    The well known Kurokawa circuit for cavity-stabilised oscillators is discussed, taking both circuit losses and frequency sensitivity of the diode mounting structure into account. It is found that modifying the original circuit by mismatching the d.c. bias port (damping resistor) leads to either increased output power or increased frequency stability. This result has been confirmed by measurements.
    Add to favourites
    Export citations
Suppression of higher-order modes in subsidiary resonance waveguide limiters
  • Author(s): E. Davidson  and  J. Helszajn
  • Source: Electronics Letters, Volume 13, Issue 19, p. 585 –586
  • DOI:  10.1049/el:19770417
  • Type: Article
  • + Show details - Hide details
  • p. 585 –586 (2)
    One shortcoming of the simple ferrite subsidiary resonance waveguide limiter is that its bandwidth is restricted by the onset of higher-order modes in its small-signal insertion-loss characteristic. The letter describes a simple mode suppressor consisting of a thin film wire metallisation along the length of the ferrite section. It includes the description of an 8.5–9.6GHz low-loss limiter in WR90 waveguide.
    Add to favourites
    Export citations
4-phase p.s.k. differential demodulator using a.s.w. delay lines
  • Author(s): Jeannine Henaff ; M. Carel ; G. Lainey ; M. Labasse
  • Source: Electronics Letters, Volume 13, Issue 19, p. 586 –588
  • DOI:  10.1049/el:19770418
  • Type: Article
  • + Show details - Hide details
  • p. 586 –588 (3)
    The letter describes a cheap and reliable solution, using acousticsurface-wave delay lines, for the differential demodulation of phase-shift-keyed digital signals at low digital rates (up to 20 Mbit/s). Results on 4-phase p.s.k. differential demodulators operating at 2.048 Mbit/s are reported in terms of bit error rate against energy per bit/noise spectral density ratio. In addition, using the same technology, a new multidifferential demodulator has been implemented. Owing to multiple differential demodulations carried out on the same signal, a significant improvement in both theoretical and experimental bit error rate is obtained.
    Add to favourites
    Export citations
Surface-acoustic-wave oscillator tuned by magnetoelastic effect
  • Author(s): G. Volluet
  • Source: Electronics Letters, Volume 13, Issue 19, p. 588 –590
  • DOI:  10.1049/el:19770419
  • Type: Article
  • + Show details - Hide details
  • p. 588 –590 (3)
    A new technique for achieving frequency modulation with a surface-acoustic-wave delay-line oscillator is reported. A 339MHz s.a.w. delay line has been fabricated on an epitaxial garnet film. A significant phase-velocity shift has been measured as a function of an inplane magnetic field. An s.a.w. oscillator has been implemented with this delay line and its frequency has been controlled by the magnetoelastic effect. A frequency shift of 600kHz (a relative variation of 1.75 × 10-3) has been obtained by changing the biasing magnetic field.
    Add to favourites
    Export citations
Voltage-controlled oscillator using an emitter-coupled differential pair
  • Author(s): S.B. Roy  and  D. Patranabis
  • Source: Electronics Letters, Volume 13, Issue 19, p. 590 –591
  • DOI:  10.1049/el:19770420
  • Type: Article
  • + Show details - Hide details
  • p. 590 –591 (2)
    A voltage-controlled oscillator using the antisymmetric transfer characteristics of an emitter-coupled differential pair of transistors is presented. Variation of the differential bias condition of this pair changes the average slope of Its transconductance parameter, thereby changing the frequency of the near harmonic mode of oscillation in a system which has been shown to produce van-der-Pol-type oscillations with passive parameter control only. Over a sufficiently wide range of frequency the distortion of this oscillation is reasonably low. A simple slope/differential-voltage relation is proposed to calculate the frequencies by computer solution of the general relation, as well as by approximate solution by using the method of small parameters. Experimental results are also presented for comparison.
    Add to favourites
    Export citations
Erratum: Technique for increasing the gain-bandwidth product of n-m.o.s. and p-m.o.s. integrated inverters
Erratum: Tunable Y-type waveguide power divider as standard mismatch
Erratum: Statistical model for the prediction of the bandwidth of an optical route
Erratum: Dielectric-ring-loaded waveguide feed
Erratum: Complex radar objects and polarisation dependence of received backscattered echoes

Most viewed content for this Journal

Article
content/journals/el
Journal
5
Loading

Most cited content for this Journal

Print this page
This is a required field
Please enter a valid email address