Page:United States Statutes at Large Volume 49 Part 2.djvu/435

 TELECO~fMU~IC.ATIOX COXVENTION. DECEMBER 9,1932. 2451 ARTICLE 4 Ohoice of Apparatus (37] § 1. The choice of radio apparatus and devices to be used in a Cbolce of apparatus. station shall be unrestricted, provided that the waves emitted satisfy the provisions of the present Regulations. [3S] § 2. However, within limits compatible with economic require- ments, the choice of transmitting, receiving, and measuring apparatus must be guided by the most recent technical progress as shown, notably, in the Opinions of the C.C.I.R. ARTICLE 5 Classification of Emissions rll] § 1. Emissions shall be divided into two classes: A. Continuous waves, B. Damped waves, defined as follows: [40] Clas8 A: Waves the successive oscillations of which are identical under fixed conditions. [41] Class B: Waves composed of successive series of oscillations the amplitude of which, after uttaining a maximum, decreases gradually. [-12] § 2. The following types of waves are derived from Class A waves: [':3] Type At. Continuous waves the amplitude or frequency of which varies under the effect of telegraph keying. lUl Type A2. Continuous waves the amplitude or frequency of which varies according to a periodic audiofrequency law, combined with telegraph keying. [45] Type AS. Continuous waves the amplitude or frequency of which varies according to a complex and variable audio- frequency law. An example of this type is radio- telephony. ["6] Type A4. Continuous waves the amplitude or frequency of which varies according to any law of frequencies greater than audible frequencies. An example of this type is television. [47] § 3. The foregoing classification into waves of types AI, A2, A3, and A4 shall not prevent the use, under conditions fixed by the ad- ministrations concerned, of waves modulated or keyed by methods not included in the definitions of types AI, A2, A3, and A4. [48] § 4. These definitions shall not relate to systems of transmitting apparatus. [49] § 5. Waves shall be indicated first by their frequency in kilo- cycles per second (kc). Following this indication there shall be indi- cated, in parentheses, the approximate length in meters. In the pres- ent Regulations, the approximate value of the wave length in meters is the quotient of the number 300,000 divided by the frequency expressed in kilocycles per second. Classification of emissions.