SEAMCAT Handbook (pdf) - Cept

7.2.2.1 User‐defined modeIn this case, the Blocking is provided in dB and represents the attenuation of the receiver at a given frequency offset(see Figure 8(b)). The resulting receiver attenuation equals the user‐defined input values. Then, the iRSS blocking at theinterferer operating frequency may be calculated as follows (Note: The It bandwidth is not considered in the iRSS blockingcalculation):iRSS blocking (f it ) = Pe + Ge + Gr ‐ L ‐ Att (f it )iRSS blocking = 33 (dBm) + 11 + 9 ‐ (32.5 + 10 log(32) + 20 log(1000)) ‐ 40(dB)iRSS blocking = ‐94.5 dBmThis can be checked by running a simulation and displaying the iRSS blocking in case of User‐defined mode calculated bySEAMCAT (Figure 45).7.2.2.2 Sensitivity modeFigure 45: Mean iRSS blocking in case of User‐defined modeIn this calculation mode the function block Max Interf Signal (f) entered by the user represents the absolute power level (indBm) of maximum interfering signal (maximum acceptable interfering power), which might be tolerated by thereceiver at a given frequency separation (see Figure 8 (a)).In this case SEAMCAT calculates the receiver attenuation, Attenuation (f), to be applied to the interfering signal byusing the following expression:Attenuation(f) = block Max Interf Signal (f) (dBm) ‐ sens vr (dBm) + C/(N+I) (dB)where: f f It - f Vr is the frequency separationsens vr is the sensitivity of the Vr (dBm) as defined in the simulation scenario.To achieve a realistic value, the user may define the sensitivity (sens vr ) as (see Figure 46 ):Sensitivity = Noise Floor + C/(N+I)Sensitivity = ‐110 dBm + 16 = ‐94 dBmFigure 46: Setting up the sensitivity in SEAMCAT52