Page:United States Statutes at Large Volume 63 Part 2.djvu/294

 (3i STAT.] ItMLTILATERAL-TELECOMM.UNICATIONS-OCT. 2. 1947 (Chapter 1, art. 1 RR) (59 55 Experimental Station: A station utilizing Hertzian waves in experiments with a view to the development of science or technique. This definition does not include amateur stations. 56 Amateur Station: A station in the amateur service. Section IV. Technical Characteristics 57 Frequency Assigned to a Station: The frequency coinciding with the centre of the frequency band in which the station is authorized to work. This frequency does not neces- sarily correspond to any frequency in an emission. 58 Bandwidth Occupied by an Emission: The band of frequencies comprising 99% of the total radiated power ex- tended to include any discrete frequency on which the power is at least 0.256 of the total radiated power. 59 Frequency Tolerance: The frequency tolerance, ex- pressed as a percentage or in cycles per second, is the maxi- mum permissible deviation, with respect to the reference fre- quency", of the corresponding characteristic frequency of an emission; the reference frequency may differ from the fre- quency assigned to a station by a fixed and specified amount 59.1 1) The concept of a reference frequency becomes necessary to include the many classes of emission now coming into use, including single side- band and multiple working. This is merely a frequency which is selected in any convenient way. The actual emission includes frequencies which are characteristic of the physical emission (for example, the carrier fre- quency itself, or a particular frequency in a sideband) as distinguished from the assigned frequency and the reference frequency, which may be regarded as mere numbers. It is intended that, consistent with the phy- sical qualities of the apparatus, one of these characteristic frequencies shall always coincide with the reference frequency. This characteristic frequency may then be referred to as the one which corresponds to the reference frequency. It is the maximum permissible difference between these two frequencies, namely the reference frequency, which is a mere number, and the corresponding characteristic frequency, which represents a physical attribute of the emission, that is meant by frequency tolerance.

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