Hydrocarbons converted to fuel gas by new process : J. A. Guyer (Chemical and Metallurgical Engineering, Vol 45, No. 6)
✍ Scribed by R.H.O.
- Publisher
- Elsevier Science
- Year
- 1938
- Tongue
- English
- Weight
- 117 KB
- Volume
- 226
- Category
- Article
- ISSN
- 0016-0032
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✦ Synopsis
Phase Modulation.--A new method of radio transmission and reception, which indicates that international broadcasts of the future will be transmitted over greater distances with four times the output of transmitters of present ratings, was described before the convention of the Institute of Radio Engineers by M. G. Crosby of RCA laboratories. Application of the method would make possible an even closer linking of nations and empires by voice than is now possible. Described by Mr. Crosby, whose work on the development covers ten years of research, as a system of " phase modulation," the new method makes possible greatly increased power at the transmitter, which results in a reduction of the annoying effects of static, man-made interference, and fading. One of the chief advantages of the new system, Mr. Crosby said, is to be realizable in either an increased power output for a given amount of transmitting equipment or a reduced amount of equipment for a given amount of power output. This fact holds promise for use in mobile craft communication such as airplane-to-ground transmission where the weight and space required must be small. It is not believed the new system will affect broadcasting on the standard frequency bands, because the most effective reception of phase modulated waves requires receivers especially designed for the system. As for the system's use in connection with television, the only statement that could be made at present would have to be speculative. It might show promise in solving some of the problems of television relaying. The receiver has the advantage of " exalting " the carrier wave and thereby substantially lessening the familiar distortion known as " selective " fading which is always present in some degree in all today's longdistance shortwave reception. The receiver, which is no more complicated than the average present-day broadcast receiver with automatic frequency control, is also capable of receiving the present amplitude modulated waves with the same distortion lessened. The new system conveys a radio signal of constant, maximum strength. Variation or modulation of the new waves is accomplished by shifting the electrical oscillations so that they either precede or lag in their normal frequency of occurrence. R. H. O.