V.H.F. and u.h.f. Gunn-effect oscillators

In this letter, the use of the Gunn device as a broadband negative resistance, somewhat analogous to a tunnel diode, is explored. v.h.f. and u.h.f. oscillators are described; the frequency is determined by an external resonant circuit and is very nearly independent of the parameters of the Gunn-effect sample.     

Switching in m.i.s.m. and m.i.s.i.m. structures

Switching has been observed in metal?thin-insulator?n-p+ structures, where the thin insulator is SiO2, or polycrystalline silicon. In this letter two alternative structures are discussed in which the n-p+ junction is replaced by a Schottky barrier. In the second device proposed two thin-insulator structures back-to-back are shown to exhibit bidirectional switching.     

Semiconductor-diode v.h.f. and u.h.f. noise sources

The v.h.f. and u.h.f. noise properties of silicon and gallium-arsenide diodes are discussed. A formula for calculating the noise output is given.     

Noise calibrator for v.h.f. and u.h.f. field-strength-measuring receivers

A simple noise generator, based on a semiconductor diode of the Zener type and suitable for use in the frequency range 30?900 MHz, can be used to check both absolute gain and noise performance of sensitive receivers.     

O.M. v.p.e. growth of AlGaSb and AlGaAsSb

The epitaxial growth of AlGaSb and AlGaAsSb alloys by o.m. v.p.e. is reported. The growth technique and the dependence of the alloy composition on the input flux of gases are discussed.     

Noise behaviour of the m.o.s.f.e.t. at v.h.f. and u.h.f.

The optimum noise figures of an m.o.s.f.e.t. at u.h.f. and at pinch-off are calculated using a simplified equivalent circuit. The noise parameters are also determined experimentally. Theory and experiment are shown to be in good agreement. Noise parameters of the m.o.s.f.e.t. for the frequency range 0.1?0.8 GHz are given.     

X and Ku band GaAs m.e.s.f.e.t.

A GaAs Schottky-barrier f.e.t. (m.e.s.f.e.t.) with a 1 ?m gate has been built, which is suitable for X band and Ku band applications. The unilateral power gain over the X band is above 9 dB and the noise figure is only 5 dB at 10 GHz.     

Bandwidth and demodulation gain in q.s.s.b. f.m.

Expressions for the bandwidth and the output to input signal/noise ratio in quasisingle sideband f.m. are derived as a function of the modulation index and the peak input amplitude to the exponentiator, to show that q.s.s.b. f.m. provides higher demodulation gains, while requiring approximately the same bandwidth as s.s.b. f.m.     

Gain expansion and intermodulation in a m.e.s.f.e.t. amplifier

A simple way of biasing and tuning an X-band m.e.s.f.e.t. for gain expansion is presented. The measured gain and phase of an experimental amplifier make possible a prediction of the third-order intermodulation using a simple power series. The calculated and measured intermodulation are in agreement with each other.     

Decoding of B.C.H. and R.S. codes with errors and erasures using continued fractions

Using continued fractions, a simplified algorithm for decoding B.C.H. and R.S. codes is developed that corrects both erasures and errors on a finite field GF(qm). The decoding method is a modification of the Forney-Belekamp technique. It is believed that the present scheme is both simpler to understand and to implement than more conventional algorithms.     

Grounding and shielding. I. Noise

Noise affects most devices. Designing adequate shielding does not have to be a black art-in fact, it should not be. Some basic understanding and the application of appropriate principles will eliminate most problems. This article is the first of a four-part series that covers the basics of noise, grounding, and shielding. This article describes various mechanisms of noise-understanding them will give immediate insight into avoiding noise problems     

Grounding and shielding. II. Grounding and return

Shielding for noise has several possible configurations, with grounding as one of the concerns in designing an effective shield. Unfortunately, some people think that picking a ground connection is the panacea for their noise problems. The author attempts to dispel that notion by illustrating some principles for grounding and return configurations     

Synthesis and analysis of d.l.t.s. spectra from m.o.s. surface states

Given Nss and ?ss as functions of energy and temperature, a procedure is developed to synthesise d.l.t.s spectra under arbitrary experimental conditions. Methods of analysis are then considered to determine Nss and ?ss from capture experiments.