摘要:

In recent years optical techniques have been utilized in a number of different signal processing systems. Certain types of operation such as multiplication and Fourier transformation are easily implemented using optical techniques, and this paper describes a selection of signal processing systems which incorporate some optical components and have possible applications in many fields such as seismology, radar, sonar, speech recognition and vibration analysis.Particular attention has been directed towards systems in which the interaction of acoustic waves and monochromatic light is used to provide a dynamic means for modulating the light with signal waveforms, and some adaptations of existing systems of this type are proposed.

DOI:10.1049/ree.1966.0049

出版商:IERE    

年代:1966

数据来源: IET

摘要:

Experimental results are presented for the type 2N502 micro-alloy graded-base transistor, which show the significance of parametric amplification at the collector-base diode in addition to normal mixing at the emitter-base diode. The latter is primarily due to the resistive non-linearity at the emitter, the parametric action at the collector being due to the non-linear junction capacitance.

DOI:10.1049/ree.1966.0051

出版商:IERE    

年代:1966

数据来源: IET

摘要:

This paper investigates the usefulness of barium titanate rods as the non-linear element of an S-band resonant cavity parametric amplifier, the pump power being at X-band. An analysis is made of the variation of reactance of a small diameter loss free rod as a function of diameter (d) and relative permittivity (ε′r). This shows that there is a large change in the resonant frequency of the cavity for a small change in the permittivity of the rod at a number of values ofπd/λ√ε′r. Taking the loss into account removes all except the smallest optimum value ofπd/λ√εr, and this is about unity.For solid polycrystalline barium titanate (ε′r≃ 5000) the optimum diameter becomes impractically small. This paper therefore deals particularly with the application of composition rods 0.2 cm diameter made of various percentages of powdered barium titanate and powdered polythene. Microwave measurements at X- and S-bands have shown that relative permittivity values between 10 and 65 can be obtained quite easily, but that these values change only by one or two percent with a d.c. biasing field of 7 kV/cm. A quality factor for these rods is defined analogously to that for varactor diodes, but the measured values compare very unfavourably with that for a typical diode.Based on one of these composition rods a resonant cavity parametric amplifier was built for a signal frequency at S-band and the pump power at X-band but no evidence of gain was detected.

DOI:10.1049/ree.1966.0052

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The metal-oxide-semiconductor transistor (MOST) offers the possibility of integrating large amounts of switching circuitry on a small area of semiconductor. Potential advantages stemming from this are low cost, reliable logic and storage arrays fabricated from active elements only in a relatively simple production process.The design of uni-channel and complementary MOST circuits, and the relationship between device parameters and circuit performance, are described in the first part of the paper. The second considers ways in which storage arrays might be assembled, with particular reference to the problems of inter- and intra-connection of circuit elements.Practical results for circuits using discrete devices are given. It is probable that integration would produce at least a doubling of the speeds obtained and a much lower power consumption.

DOI:10.1049/ree.1966.0053

出版商:IERE    

年代:1966

数据来源: IET

摘要:

A 3-cm pulsed Doppler radar constructed at the Royal Radar Establishment is described and the use of this equipment to increase knowledge of atmospheric precipitation processes is explained. With the aerial pointing vertically in widespread rain it is possible to deduce the drop size distribution in the free atmosphere and to study its variation with height. In showers it is possible to derive height-time sections of both vertical air motion and maximum particle velocity; examples of these sections are shown and discussed. A new mobile Doppler radar designed for investigation of thunderstorms is briefly mentioned. Finally, the application of Doppler radar operating at low angles of elevation to the measurement of horizontal convergence and vertical velocity of the air during widespread rain is described and initial results shown.

DOI:10.1049/ree.1966.0054

出版商:IERE    

年代:1966

数据来源: IET

摘要:

An essential feature of Bosnia's theory of the three-port stripline junction circulator is the smallness of the splitting of a degenerate pair of normal modes. This results in only a small asymmetric distortion of the isotropic field configuration in the disks. A new junction geometry is described which makes use of a garnet ring around a ceramic disk instead of the conventional garnet disk shape. When the degenerate modes of the two isotropic configurations are identical, the circulation adjustment for each geometry is nearly the same. This new circulator geometry is characterized by a low insertion loss and a large thermal capacity.

DOI:10.1049/ree.1966.0056

出版商:IERE    

年代:1966

数据来源: IET

摘要:

The SI system of units is based on the MKSA system with the addition of specifications of units for temperature and luminous intensity. There are also changes to several derived units.

DOI:10.1049/ree.1966.0057

出版商:IERE    

年代:1966

数据来源: IET