摘要:

An introduction is given to the concept of colour-display systems with mechanical field-scan. The optical elements are of fundamental importance to this kind of display and various optical aspects are discussed, including the advantages of direct-viewing systems over projection, the application of cylindrical optical elements and the size of moving optical elements in relation to the required picture size. This discussion leads to the basic concept of a rotating mirror—or lens drum with a magnifying cylindrical mirror.The fundamental properties of these two solutions are compared and the favoured system with the banana tube is described in detail. The basic requirements of this system with respect to the design of the tube, the optical elements and the mechanical components are dealt with. Finally, some inherent advantages of the present system are discussed and possible further improvements are mentioned.

DOI:10.1049/pi-b-2.1961.0100

出版商:IEE    

年代:1961

数据来源: IET

摘要:

The unconventional system of beam deflection and spot formation in the banana tube is considered in detail. The discussion of electron optics includes a formulation of the requirements for the permanent-magnetic deflecting field, with a detailed description of the effect of this field on the electron spot, as well as the scanning and focusing means employed.The tube technology is considered in broad outline, including certain aspects of manfacture.

DOI:10.1049/pi-b-2.1961.0101

出版商:IEE    

年代:1961

数据来源: IET

摘要:

The major mechanical components of the banana-tube colour-television display system are described, together with the materials and manufacturing techniques used to achieve results consistent with the requirements of the system. Development has proceeded to a stage where a fully engineered version more suitable for quantity production can be considered.

DOI:10.1049/pi-b-2.1961.0102

出版商:IEE    

年代:1961

数据来源: IET

摘要:

The circuits necessary to operate the banana-tube colour display are described under the headings of tube supplies, drum synchronization and video-signal processing. Circuit techniques which are peculiar to this form of colour-picture display are described in some detail.

DOI:10.1049/pi-b-2.1961.0103

出版商:IEE    

年代:1961

数据来源: IET

摘要:

The principal sources of errors in colour reproduction of the banana tube are the colour phosphors employed, the finite spot size of the tube and the self-decoding colour circuits. The errors due to these causes are analysed, particular attention being given to the use of an incorrect green primary phosphor and to methods of evaluating the importance of random errors in the chromaticity and luminance of the phosphors. Methods of alleviating errors due to the incorrect green primary by special correction circuits are discussed.

DOI:10.1049/pi-b-2.1961.0104

出版商:IEE    

年代:1961

数据来源: IET

摘要:

The many factors which determine the potentialities and limitations of the banana tube as a possible solution to the colour-display problem are considered in some detail. Limitations imposed by tolerances set by the requirements of the system are stated and an appraisal of the picture quality is made. Some indication of possible cost compared with other displays and an overall appraisal and indication of future possibilities are given.

DOI:10.1049/pi-b-2.1961.0105

出版商:IEE    

年代:1961

数据来源: IET

摘要:

A new method is described of predicting an aerial radiation pattern from near-field measurements. The essence of this method is the expansion of the radiated field in terms of a series of radially expanding modes. The amplitude and phase of each mode are calculated by a Fourier analysis of the measured near field, and the radiation pattern is obtained as a Fourier series containing these measured amplitudes and phases. The theory is described in detail for a cylindrical (2-dimensional) aerial, and experimental results are presented to confirm the validity of this theory. The way in which the method may be extended to 3-dimensional aerials is explained. The method has the advantage that it can be applied anywhere in the near field

DOI:10.1049/pi-b-2.1961.0109

出版商:IEE    

年代:1961

数据来源: IET

摘要:

Experimental and theoretical reradiation polar diagrams are compared for theH-plane of a rectangular pyramidal horn. A distinction is made between scattering, which is found to be due to the presence of higher modes, and reradiation, which is mainly responsible for the shadow. The distinction applies to receiving aerials in general, and a theory is presented in which every receiving aerial is regarded as a potential perfect absorber. The imperfection in normal operation is explained by the extent to which the incident field fails to correspond to the ‘complementary’ field that perfect absorption would require.

DOI:10.1049/pi-b-2.1961.0110

出版商:IEE    

年代:1961

数据来源: IET

摘要:

Departure of the source impedance of a noise generator from the nominal value gives rise to an uncertainty in the measurement of noise factor. A critical examination of the problem shows that, to obtain an uncertainty on this account of less than 2%, a source v.s.w.r.of about 0.98 is required. Because existing noise generators seldom meet this requirement and because there is a need for more consistent measurements of noise than those obtained hitherto at frequencies up to about 1 200 Mc/s, a new noise generator has been developed.A description of the design, construction, calibration and use of this noise generator is given. It employs a precision source resistor of 50Ω and a pair of specially developed thermionic diodes (E2790), using a form of diode mount designed to eliminate the effects of diode capacitance so that a v.s.w.r.better than 0.98 is obtained at all frequencies in the range. It is an absolute noise generator with an accuracy in noise level of ±2% at frequencies up to about 300 Mc/s, but requires calibration at a single level for frequencies up to 1 250 Mc/s. At present, this has been achieved with an estimated uncertainty of about ±5% in noise level.

DOI:10.1049/pi-b-2.1961.0111

出版商:IEE    

年代:1961

数据来源: IET

摘要:

After referring to unsuccessful attempts based on a wafer-type mount, a coaxial unit is described which operates over the frequency band 26-40 Gc/s, and is mechanically interchangeable with American crystal 1N 53. The new crystal employs a silicon point contact of high sensitivity, and the mount was designed to give best v.s.w.r. over the entire bandwidth.The design technique is described in detail and experimental data are summarized. Notwithstanding some difficulty in manufacturing to the required sensitivity, a broad-band design has been achieved and the capabilities of Q-band detector crystals have been gauged.

DOI:10.1049/pi-b-2.1961.0112

出版商:IEE    

年代:1961

数据来源: IET