# Electrical Engineers, Proceedings of the Institution of

## Filter Results

Displaying Results 1 - 25 of 28
• ### Digital video: sub-Nyquist sampling of Pal colour signals

Publication Year: 1978, Page(s):779 - 786
Cited by:  Papers (5)
| |PDF (1239 KB)

The use of sub-Nyquist sampling frequencies for coding monochrome video signals or the separate components of colour signal is well known as a means of reducing bit rates. However, such techniques are usually unsatisfactory for coding composite colour signals. This paper describes a technique which may be used for composite Pal signals in which a sub-Nyquist sampling frequency equal to twice the c... View full abstract»

• ### Residue-calculus solution of the TM10-mode problem in circular corrugated waveguides

Publication Year: 1978, Page(s):787 - 792
| |PDF (680 KB)

The problem of finding the propagation behaviour of the TM10 mode in a circular corrugated waveguide is formulated using the residue-calculus technique. This method proves to be computationally efficient, yields very accurate results and provides a prior assurance of satisfying edge conditions. Graphical results are presented to show the effect of changing corrugation depths on the propagation con... View full abstract»

• ### Electrically short monopole antennas with dielectric or ferrite coatings

Publication Year: 1978, Page(s):793 - 803
Cited by:  Papers (10)
| |PDF (1434 KB)

A comprehensive analysis of the electrically-small material-clad monopole is performed by representing the various fields by discrete and continuous eigenvalue spectrums. The cladding creates a dominant quarter-wavelength resonant-cavity effect whereby the leakage of radiation at the terminal plane is transformed into a low impedance at the annular feed. The mode coupling taking place at both feed... View full abstract»

• ### Medium-wave propagation in built-up areas

Publication Year: 1978, Page(s):804 - 808
Cited by:  Papers (3)
| |PDF (519 KB)

An investigation has taken place into the problems of medium frequency (m.f.) ground-wave propagation in built-up areas. Measurements were made which showed that, in such conditions, the field-strength/distance relationship is often different from that expected on the basis of conventional theories. These conventional theories have been extended and applied to explain the results. A computer predi... View full abstract»

• ### Utilisation of radiosonde data in propagation research

Publication Year: 1978, Page(s):809 - 810
| |PDF (196 KB)

A computer program is presented for the calculation of the spatial distribution of radio refractivity and potential refractive modulus using data obtained from radiosonde ascents. View full abstract»

• ### Decomposition technique for acquiring combined pseudorandom-noise signals

Publication Year: 1978, Page(s):811 - 814
| |PDF (637 KB)

A new technique for fast acquisition of pseudorandom-noise (p.r.n.) signals is derived. By considering that the period of a long combined p.r.n. sequence is equal to the product of the periods of its component sequences, we found that phase synchronisation can be achieved much easier after directly decomposing the received p.r.n. sequence into its component sequences, thus eliminating the sequenti... View full abstract»

• ### Two-way transmission of baseband digital signals

Publication Year: 1978, Page(s):815 - 824
| |PDF (1358 KB)

This paper investigates a novel technique for the transmission of baseband digital signals over a cable in both directions simultaneously. The arrangement relies on the use of narrow transmitted pulses which, after suitable line equalisation, yield substantially wider received signals. Directional separation is then obtained by exploiting the local difference between the transmitted and received s... View full abstract»

• ### Transverse spreading of a high-field domain in a bulk negative-conductance semiconductor. Two dimensional computer simulation and equivalent-circuit model

Publication Year: 1978, Page(s):826 - 830
| |PDF (612 KB)

Transverse spreading of a high-field domain in negative differential conductivity semiconductors has been analysed by a 2-dimensional computer simulation for various conditions. The results show that the transverse-spreading phenomena are very sensitive to the initial domain size in addition to the bias field, sample length and other parameters. During the domain spreading in the transverse direct... View full abstract»

• ### Evaluation of the reluctance-augmentation principle in shaded-pole motors

Publication Year: 1978, Page(s):831 - 835
Cited by:  Papers (7)
| |PDF (682 KB)

This paper examines the principle of reluctance augmentation, as applied to shaded-pole motors, to assess its value. The assessment is accomplished using a computer-borne analysis to redesign an existing commercially manufactured motor. The characteristics of the redesigned machines obtained with and without the use of the reluctance-augmentation effect are then compared. It is shown that the grea... View full abstract»

• ### Stability study of induction motors under variable-frequency modes in the presence of external inductors

Publication Year: 1978, Page(s):836 - 840
Cited by:  Papers (1)
| |PDF (515 KB)

With variable-frequency (v.f.) modes of speed control of induction motors, investigation reveals that the low-frequency instability zones exhibited by machines having low inertia constants can be avoided by connecting suitable inductors externally to the rotor circuit (or stator leads). For machines having large inertia constants, which may not exhibit low-frequency instability zones, the inherent... View full abstract»

• ### High-frequency instabilities in variable-reluctance stepping motors

Publication Year: 1978, Page(s):841 - 847
Cited by:  Papers (6)
| |PDF (900 KB)

An analytical study of the dynamic instability of a variable-reluctance stepping motor is described. This type of instability occurs at speeds where the machine is operating essentially as a synchronous device, and is characterised by the presence of a low-frequency velocity oscillation superimposed on the synchronous speed. The frequency of the mechanical oscillation and the applied stepping freq... View full abstract»

• ### Plugging of capacitor motors

Publication Year: 1978, Page(s):848 - 852
| |PDF (567 KB)

This paper analyses the braking characteristics of single-phase capacitor motors by plugging, and presents a method of selecting the best value of capacitance for quick braking. The effect of displacement angle and the turns ratio of the main and starting windings on braking performance have been investigated. It is shown that pole-changing windings can also be used for braking with advantage. View full abstract»

• ### Parameters and losses of hydrogenerator damping systems

Publication Year: 1978, Page(s):853 - 856
| |PDF (542 KB)

The paper shows the necessity for: more exact methods to calculate and measure the parameters and damping system losses of highly utilised hydrogenerators; a more exact method for measuring the damping rod currents, by means of Hall's generators, and for the design of a current measurer and the measuring circuit, and a new method to calculate losses in the damping system of a large synchronous hyd... View full abstract»

• ### Advanced theory of the delay of the commutating pole flux of a d.c. machine, and the improved machine that applies it

Publication Year: 1978, Page(s):857 - 864
| |PDF (710 KB)

When the response of the commutating flux is delayed, the appropriate electromotive force for commutation is not induced in the armature winding. The time delay of the commutating pole flux is due to eddy currents induced in the yoke or liners, and results in brush spark. The theory of time delay of the commutating pole flux has been derived by Rudenberg. However, it has been pointed out that the ... View full abstract»

• ### Improvements in high-performance lowpass filters using coupled windings

Publication Year: 1978, Page(s):865 - 872
Cited by:  Papers (1)
| |PDF (735 KB)

The use of mutually coupled windings in lowpass filters is considered. The addition of a small auxilary winding to the main filter choke allows the fundamental ripple component to be tuned outÂ¿, giving a much improved filter characteristic without the addition of any further components. Filters using this principle have been termed mutual-type filtersÂ¿. The transfer functions and conditions fo... View full abstract»

• ### Harmonics produced by direct current in convertor transformers

Publication Year: 1978, Page(s):873 - 878
Cited by:  Papers (13)
| |PDF (699 KB)

Test and analytical procedures are described that determine the relationship between direct current and resultant harmonics in a convertor transformer. It is shown that a linear relationship exists between lower-order harmonics and direct current. The effect of fluxingÂ¿ the transformer is also shown, and it is found that under-fluxingÂ¿ a transformer in the presence of direct current has little... View full abstract»

• ### Power-system state estimation using linear programming

Publication Year: 1978, Page(s):879 - 885
Cited by:  Papers (57)
| |PDF (801 KB)

The problem of estimating the state variables from measurements in an electric-power system is considered. The conventional linearised least-squares solution is shown to be ineffective in the presence of gross measurement errors. Reformulating the problem as a linear program leads to a state estimator that combines the advantages of noise filtering and bad-data elimination, and may be implemented ... View full abstract»

• ### Discussion on 'Dynamic-stability analysis of synchronous machines including damper circuits, automatic voltage regulator and governor'

Publication Year: 1978
| |PDF (139 KB)
• ### N.I.C. for error compensation of a current transformer

Publication Year: 1978, Page(s):887 - 888
| |PDF (287 KB)
• ### Directional relay offering a continuously adjustable operating zone

Publication Year: 1978, Page(s):888 - 889
| |PDF (245 KB)
• ### Sensed reconnection of induction-motor supplies

Publication Year: 1978
| |PDF (116 KB)
• ### Frequency-response estimates using discrete signals and the radix-2 f.f.t.

Publication Year: 1978, Page(s):891 - 894
| |PDF (500 KB)

Large errors occur when using pseudorandom binary sequences and the radix-2 fast Fourier transform (f.f.t.) to estimate the frequency response of linear systems. The reason for this phenomenon is discussed and it is shown that using an augmented p.r.b.s. accurate estimates of frequency responses can be made with the radix-2 f.f.t. Augmented p.r.b.s. has a further advantage, namely that of a zero m... View full abstract»

• ### Performance prediction of a wide-angle limited-motion rotary actuator

Publication Year: 1978, Page(s):895 - 898
Cited by:  Papers (7)
| |PDF (523 KB)

A doubly excited, doubly salient, concentrated winding type of rotary actuator structure is examined. Neglect of iron-member reluctances predicts a flat torque characteristic over the normal limited range of movement. In practice, a flat characteristic is not achieved. The reason for this is shown, by analysis and measurement, to be due to the significance of the iron reluctances both before and a... View full abstract»

• ### POLFAC ߝ a routine to find the factors of a polynomial with real coefficients

Publication Year: 1978, Page(s):899 - 901
| |PDF (350 KB)

This routine is suitable for inclusion in engineering-design programs that involve analysis of transients, whether these are to be batch run or interactive, and where speed, low storage and certainty of result are essential. Errors depend on register length, and 11 accurate decimal figures are obtained for 20th-degree polynomials with distinct roots and double-length working. Algol, Fortran and Ba... View full abstract»

• ### New expressions and some more precise values for Student's t-factor

Publication Year: 1978, Page(s):902 - 904
| |PDF (302 KB)

This paper gives a 6-figure table of Student's t-factors for confidence levels corresponding to the Â± Â¿, Â± 2Â¿ and Â± 3Â¿ limits of a normal distribution. These values have not hitherto been well tabulated, but they are frequently needed when expressing the random uncertainties of measurements on radio frequency and microwave components. Some closed expressions for the integral required in the ... View full abstract»

## Aims & Scope

The Proceedings of the Institution of Electrical Engineers was published by the IET between 1963 and 1979.

Full Aims & Scope