Page:United States Statutes at Large Volume 54 Part 2.djvu/375

 54STAT.] MULTILATERAL-TELECOMMUNICATION-APR. 8, 1938 APPENDIX 3 Table of Frequency-Band Widths Occupied by the Emissions (See articles 5 and 6) The frequency bands necessary for the various types of transmis- sion, at the present state of technical development, are indicated below. This table is based solely upon amplitude modulation. For frequency or phase modulation, the band widths necessary for the various transmissions are many times greater. Type of transmission Total width of the band in cycles For transmission with two sidebands AO Continuous waves, no signaling Al Telegraphy, pure, con- Numerically equal to the telegraph speed in tinuous wave bauds for the fundamental frequency, 3 Morse code times this width for the 3d harmonic, Baudot code etc. Stop-start printer [For a code of 8 time elements (dots or blanks) per letter and 48 time elements per word, the speed in bauds shall be equal to 0.8 times the speed in words per minute.] Scanning-type printer 300-1,000, for speeds of 50 words per min- ute, according to the conditions of opera- tion and the number of lines scanned (for example, 7 or 12). (Harmonics are not considered in the above values.) A2 Telegraphy modulated Figures appearing under Al, plus twice the to musical frequency highest modulation frequency. A3 Commercialradioteleph- Twice the number indicated by the C.C .I.F. ony Opinions (about 6,000 to 8,000).' Broadcasting 15,000 to 20,000. A4 Facsimile Approximately the ratio between the num- ber of picture components 2 to be trans- mitted and the number of seconds neces- sary for the transmission. A5 Television Approximately the product of the number of picture components 3 multiplied by the number of pictures transmitted per second. I'It irecognied that the band width may be wider for multiplechannel radiotelephony and secret radio telephony. 2 Two picture components, one black and one white, constitute a cycle; thus, the modulation freqmeny equals one half the number of components transmitted per second. 1595 Ant, pp. 1427,1429.

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