DOI:10.1049/ree.1972.0048

出版商:IERE    

年代:1972

数据来源: IET

摘要:

The Josephson effects, which arise at a suitable junction between two pieces of superconducting material, have several applications at millimetre and submillimetre wavelengths. Devices based on the effects can be used as video detectors, harmonic mixers and frequency analysers, often with unique properties. These and other possible applications are described, and the current experimental situation using the ‘point contact’ type of junction is outlined.

DOI:10.1049/ree.1972.0049

出版商:IERE    

年代:1972

数据来源: IET

摘要:

Measurements of electron temperature in the ionosphere using rocket and satellite-borne probes have been made for some years by the Department of Electron Physics and Space Research of Birmingham University, using the experimental technique described. The apparatus, in its latest form, has been developed to provide a more compact and reliable system by exploiting the advantages of linear integrated circuits over the discrete component circuitry used previously. In considering the performance of the experiment, particular attention has been paid to the stability problems associated with the closed-loop system employed.

DOI:10.1049/ree.1972.0050

出版商:IERE    

年代:1972

数据来源: IET

DOI:10.1049/ree.1972.0051

出版商:IERE    

年代:1972

数据来源: IET

摘要:

The novel interconnexion of a bridge timing circuit, a switched comparator, and a complementary transistor latching scheme, permits the design of a monostable circuit which consumes ‘zero’ standby power and has a pulse widthT = CR±3% (Cand R being externally connected timing components) for a rail voltage in the range 3V to 30V.

DOI:10.1049/ree.1972.0052

出版商:IERE    

年代:1972

数据来源: IET

摘要:

This paper describes the lead-tin telluride system and its application to the fabrication of fast sensitive infra-red detectors both as single elements and arrays. The electrical and optical properties are discussed with emphasis on the sensitivity of the single elements, and the uniformity in both spectral response and sensitivity for the arrays. (12.1 μm, 800, 1) values up to 2.9 × 1010cm Hz½watt−1have been achieved for unbiased single detectors and 14×1 element arrays have been measured with a spread in D*λvalues as good as 2.2 : 1.

DOI:10.1049/ree.1972.0053

出版商:IERE    

年代:1972

数据来源: IET

摘要:

The frequencies of the hydrogen cyanide and water vapour laser emissions have been measured directly against a fundamental frequency standard by harmonic generation and mixing and beat frequency detection in point contact diodes. The value obtained for the HCN laser (337 μm) is 890 760.2 ± 0.2 MHz and for the H2O laser (118 μm) 2 527 952.5 ± 1.5 MHz. In addition some preliminary measurements have been made on the 10.7 THz H2O laser line.

DOI:10.1049/ree.1972.0054

出版商:IERE    

年代:1972

数据来源: IET

摘要:

This paper establishes the conditions under which maximum power transfer in a parametric circuit with port immittances having positive real parts will be achieved with conjugate matching at input and output, and links these results with earlier work which showed, for modulator and mixer circuits, when source and load resistance might also be equal.

DOI:10.1049/ree.1972.0055

出版商:IERE    

年代:1972

数据来源: IET

摘要:

This paper describes a photoconductive detector which, through the use of a microwave bias, is capable of demodulating a low-level signal at information bandwidths greater than 1 MHz. The principle of operation is described and the advantages over d.c. biased photoconductors highlighted. The dependence of photocurrent gain on semiconductor properties and limitations on performances are discussed. A system operating at 1 μm wavelength using a Gunn oscillator and miniaturized microwave components is described. This detector, which uses germanium as the photoconductor, has a noise equivalent power (n.e.p.) of 5×10−1W in a noise bandwidth of 10 MHz and a 10−90% rise-time of 80 ns. The system has also been operated with silicon and indium arsenide. Finally, a comparison is made between microwave biased photoconductive detectors and avalanche photodiodes.

DOI:10.1049/ree.1972.0056

出版商:IERE    

年代:1972

数据来源: IET

摘要:

In a device using binary rate multipliers and reversible counters (up/down counters or bidirectional counters) to perform arithmetic operations, the result of computations could oscillate up and down around the exact answer. This oscillation can be minimized by means of backlash units (digital filters). However the introduction of the backlash units will cause an additional error on the computing time. This paper analyses the additional error in an experiment with a system performing multiplication.

DOI:10.1049/ree.1972.0057

出版商:IERE    

年代:1972

数据来源: IET