Operating Manual Vol 1 - ES Documentation

SMIQDigital Modulation2.10.1.3 FSK ModulationFor FSK modulation, frequency shifts are assigned to the modulation symbols. The modulation index hof this digital frequency modulation is determined byh = 2⋅∆ f / f SymbThe symbol rate f SYMB can be freely set to a maximum of 2.5 Msymb/s for all FSK modulations. WithGMSK selected, the frequency deviation∆f (FSK deviation) cannot be set since the modulation index isfixed to a value of h = 0.5. The following table shows the assignment of modulation symbols andfrequency deviations for the different FSK methods.Table 2-7Frequency deviations for FSK methodsMod. symbol 2FSK, GFSK MSK, GMSK 4FSK APCO0 −∆f −∆f −∆f +∆f/31 +∆f +∆f −∆f/3 +∆f10 - - +∆f/3 −∆f/311 - - +∆f −∆fAll FSK modulation methods can be combined with COS, SQR_COS, GAUSS and BESSEL basebandfilters. A combination with IS-95 filters is not permissible.2.10.1.4 CodingModulation symbols are coded directly before an assignment of I and Q values or frequency shifts.Coding is thus directly related with modulation methods which is the reason why codings are not freelycombinable with modulation methods. The following table shows which combinations are possible.Table 2-8Possible combination of modulation method and codingCoding Selection CODING Combinable with MOD TYPE Example of useDifferential coding DIFF all except for 256QAMGray + differentialcodingGRAY+DIFF all except for 256QAM D8PSK for VDRGSM differential coding GSM FSK, GFSK, GMSK Mobile radio standard GSMπ/4DQPSK differentialcodingNADC; PDC;..π/4DQPSKMobile radio standards NADC,PDC, PHS, APCO25, TFTS,TETRAPhase differential coding INMARSAT QPSK ISAT Satellite system INMARSAT-MPhase differential coding PHASE DIFF 16 , 32 , 64 , 256 QAM DVB in line with ETS 300429VDL coding VDL 8PSK VHF Digital LinkThe effect of differential coding on π/4DQPSK has been described in section 'Modulation π/4DQPSK'.Common coding types are listed in the following table.1125.5555.03 2.89E-9