ITU-R SM 1138-2-2008 Determination of necessary bandwidths including examples for their calculation and associated examples for the designation of emissions《必要带宽的确定及其计算举例与相应的发射标识的举.pdf
《ITU-R SM 1138-2-2008 Determination of necessary bandwidths including examples for their calculation and associated examples for the designation of emissions《必要带宽的确定及其计算举例与相应的发射标识的举.pdf》由会员分享,可在线阅读,更多相关《ITU-R SM 1138-2-2008 Determination of necessary bandwidths including examples for their calculation and associated examples for the designation of emissions《必要带宽的确定及其计算举例与相应的发射标识的举.pdf(8页珍藏版)》请在麦多课文档分享上搜索。
1、 Rec. ITU-R SM.1138-2 1 RECOMMENDATION ITU-R SM.1138-2 Determination of necessary bandwidths including examples for their calculation and associated examples for the designation of emissions (1995-2007-2008) Scope This Recommendation serves as a basis for the determination of necessary bandwidths of
2、 emissions under amplitude, frequency and pulse modulation by various types of signals. Sample calculations and designation of emissions are also provided. The ITU Radiocommunication Assembly, considering a) that the assignment of frequencies requires the determination of the necessary bandwidth of
3、emissions; b) that necessary bandwidth is a key data element of all automated spectrum-management systems, recommends 1 that the formulae given in Annex 1 shall be used to calculate the necessary bandwidth when required by the Radio Regulations (RR). Annex 1 Determination of necessary bandwidths, in
4、cluding examples for their calculation and associated examples for the designation of emissions 1 The necessary bandwidth is not the only characteristic of an emission to be considered in evaluating the interference that may be caused by that emission. 2 In the formulation of the table, the followin
5、g terms have been employed: Bn: necessary bandwidth (Hz) B: modulation rate (Bd) N: maximum possible number of black plus white elements to be transmitted per second, in facsimile M: maximum modulation frequency (Hz) C: sub-carrier frequency (Hz) D: peak deviation, i.e. half the difference between t
6、he maximum and minimum values of the instantaneous frequency. The instantaneous frequency (Hz) is the time rate of change in phase (rad) divided by 2 t: pulse duration (s) at half-amplitude 2 Rec. ITU-R SM.1138-2 tr: pulse rise time (s) between 10% and 90% amplitude K: an overall numerical factor wh
7、ich varies according to the emission and which depends upon the allowable signal distortion. In the case of orthogonal frequency division multiplexed multi-carrier signal, K is the number of active sub-carriers as defined by equation (52) in Recommendation ITU-R SM.328 Nc: number of baseband channel
8、s in radio systems employing multichannel multiplexing fp: continuity pilot sub-carrier frequency (Hz) (continuous signal utilized to verify performance of frequency-division multiplex systems) Ns: frequency separation between two sub-carriers (kHz). Necessary bandwidth Description of emission Formu
9、la Sample calculation Designation of emission I. NO MODULATING SIGNAL Continuous wave emission NONE II. AMPLITUDE MODULATION 1. Signal with quantized or digital information Continuous wave telegraphy, Morse code Bn= BK K = 5 for fading circuits K = 3 for non-fading circuits 25 words per minute B = 2
10、0, K = 5 Bandwidth: 100 Hz 100HA1AAN Telegraphy by on-off keying of a tone modulated carrier, Morse code Bn= BK + 2M K = 5 for fading circuits K = 3 for non-fading circuits 25 words per minute B = 20, M = 1 000, K = 5 Bandwidth: 2 100 Hz = 2.1 kHz 2K10A2AAN Selective calling signal using sequential
11、single frequency code, single-sideband full carrier Bn= M Maximum code frequency is: 2 110 Hz M = 2 110 Bandwidth: 2 110 Hz = 2.11 kHz 2K11H2BFN Direct-printing telegraphy using a frequency shifted modulating sub-carrier, with error-correction, single-sideband, suppressed carrier (single channel) Bn
12、= 2M + 2DK 2BM = B = 50 D = 35 Hz (70 Hz shift) K = 1.2 Bandwidth: 134 Hz 134HJ2BCN Telegraphy, multichannel with voice frequency, error-correction, some channels are time-division multiplexed, single-sideband, reduced carrier Bn= highest central frequency + M + DK 2BM = 15 channels; highest central
13、 frequency is: 2 805 Hz B = 100 D = 42.5 Hz (85 Hz shift) K = 0.7 Bandwidth: 2 885 Hz = 2.885 kHz 2K89R7BCW 2. Telephony (commercial quality) Telephony, double-sideband (single channel) Bn= 2M M = 3 000 Bandwidth: 6 000 Hz = 6 kHz 6K00A3EJN Telephony, single-sideband, full carrier (single channel) B
14、n= M M = 3 000 Bandwidth: 3 000 Hz = 3 kHz 3K00H3EJN Telephony, single-sideband, suppressed carrier (single channel) Bn= M lowest modulation frequency M = 3 000 lowest modulation frequency = 300 Hz Bandwidth: 2 700 Hz = 2.7 kHz 2K70J3EJN Rec. ITU-R SM.1138-2 3 Necessary bandwidth Description of emis
15、sion Formula Sample calculation Designation of emission 2. Telephony (commercial quality) (cont.) Telephony with separate frequency modulated signal to control the level of demodulated speech signal, single-sideband, reduced carrier (Lincompex) (single channel) Bn= M Maximum control frequency = 2 99
16、0 Hz M = 2 990 Bandwidth: 2 990 Hz = 2.99 kHz 2K99R3ELN Telephony with privacy, single-sideband, suppressed carrier (two or more channels) Bn= NcM lowest modulation frequency in the lowest channel Nc= 2 M = 3 000 lowest modulation frequency = 250 Hz Bandwidth: 5 750 Hz = 5.75 kHz 5K75J8EKF Telephony
17、, independent sideband (two or more channels) Bn= sum of M for each sideband 2 channels M = 3 000 Bandwidth: 6 000 Hz = 6 kHz 6K00B8EJN 3. Sound broadcasting Sound broadcasting, double-sideband Bn= 2M M may vary between 4 000 and 10 000 depending on the quality desired Speech and music M = 4 000 Ban
18、dwidth: 8 000 Hz = 8 kHz 8K00A3EGN Sound broadcasting, single-sideband, reduced carrier (single channel) Bn= M M may vary between 4 000 and 10 000 depending on the quality desired Speech and music M = 4 000 Bandwidth: 4 000 Hz = 4 kHz 4K00R3EGN Sound broadcasting, single-sideband, suppressed carrier
19、 Bn= M lowest modulation frequency Speech and music M = 4 500 lowest modulation frequency = 50 Hz Bandwidth: 4 450 Hz = 4.45 kHz 4K45J3EGN 4. Television Television, vision and sound Refer to relevant ITU-R documents for the bandwidths of the commonly used television systems Number of lines: 625 Nomi
20、nal video bandwidth = 5 MHz Sound carrier relative to video carrier: 5.5 MHz Total vision Bandwidth: 6.25 MHz FM sound bandwidth including guardbands: 750 kHz RF channel Bandwidth: 7 MHz 6M25C3F - 750KF3EGN 5. Facsimile Analogue facsimile by sub-carrier frequency modulation of a single-sideband emis
21、sion with reduced carrier, monochrome Bn= C + 2N+ DK K = 1.1 (typically) N = 1 100 corresponding to an index of cooperation of 352 and a cycler rotation speed of 60 rpm. Index of cooperation is the product of the drum diameter and number of lines per unit length. C = 1 900 D = 400 Hz Bandwidth: 2 89
22、0 Hz = 2.89 kHz 2K89R3CMN Analogue facsimile; frequency modulation of an audio frequency sub-carrier which modulates the main carrier, single-sideband suppressed carrier Bn= 2M + 2DK M = 2NK = 1.1 (typically) N = 1 100 D = 400 Hz Bandwidth: 1 980 Hz = 1.98 kHz 1K98J3C - 4 Rec. ITU-R SM.1138-2 Necess
23、ary bandwidth Description of emission Formula Sample calculation Designation of emission 6. Composite emissions Double-sideband, television relay Bn= 2C + 2M + 2D Video limited to 5 MHz, audio on 6.5 MHz, frequency modulated sub-carrier, sub-carrier deviation = 50 kHz: C = 6.5 106D = 50 103Hz M = 15
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