The occupied bandwidth (Hz) for 0.01 may also be calculated from the empirical equation:  L (11) is the relative build-up time of the shortest pulse of the telegraph signal, as defined in 1.10. recommends The occupied bandwidth so calculated is hardly affected by the of the telegraph signal, whereas the outof-band spectrum depends largely on this shape. The maximum divergence between the results obtained by equation (11) and those obtained by exact calculations, is as follows: 3% for  0; 2 m  20 9% for  m  20 10% for 20.  m The list above shows the limits within which equation (11) can be used with reasonable accuracy. The percentages indicated apply to the lower limit of They are less for the higher limit. m. Finally, Fig. 16 the results of calculations and measurements of occupied bandwidth employing different methods. 1.4 Shaping of the telegraph signal by means of filters See Annex 1, § 3. However, the use of minimum overshoot filters is not essential, when the transmitter is required to operate at more than two frequencies, for example in the case of diplex. 1.5 Adjacent-channel interference See 1, § 1.6. 1.6 Build-up time of the signal An out-of-band spectrum close to the limiting curve described in § 1.8 corresponds to a build-up time equal to about 8% of the initial duration of the telegraph dot, i.e. about 1/12 provided that an B, adequate filter is used for signal shaping. 1.7 Bandwidth occupied, for unshaped signals For the purpose of comparison with the formulae in § 1.1, it may be mentioned that, for a sequence of equal and rectangular (zero build-up time) mark and space signals, the occupied bandwidth is given by the following formulae: 2.6 1.4 within 2% for 2 8    D B m 2.2 3.1 within 2% for 8 20 D  B m
The occupied bandwidth L (Hz) for  0.01 may also be calculated from the empirical equation: (11) is the relative build-up time of the shortest pulse of the telegraph signal, as defined in recommends 1.10. The occupied bandwidth so calculated is hardly affected by the of the telegraph signal, whereas the outof-band spectrum depends largely on this shape. The maximum divergence between the results obtained by equation (11) and those obtained by exact calculations, is as follows: 3% for  0; 2 m  20 9% for  m  20 10% for  m 20. The list above shows the limits within which equation (11) can be used with reasonable accuracy. The percentages indicated apply to the lower limit of m. They are less for the higher limit. Finally, Fig. 16 the results of calculations and measurements of occupied bandwidth employing different methods. 1.4 Shaping of the telegraph signal by means of filters See Annex 1, § 3. However, the use of minimum overshoot filters is not essential, when the transmitter is required to operate at more than two frequencies, for example in the case of diplex. 1.5 Adjacent-channel interference See 1, § 1.6. 1.6 Build-up time of the signal An out-of-band spectrum close to the limiting curve described in § 1.8 corresponds to a build-up time equal to about 8% of the initial duration of the telegraph dot, i.e. about 1/12 B, provided that an adequate filter is used for signal shaping. 1.7 Bandwidth occupied, for unshaped signals For the purpose of comparison with the formulae in § 1.1, it may be mentioned that, for a sequence of equal and rectangular (zero build-up time) mark and space signals, the occupied bandwidth is given by the following formulae: 2.6 D  1.4 B within 2% for 2  m  8 2.2 D  3.1 B within 2% for 8 m 20
R-REC-SM.328-11-200605-I!!MSW-E.docx