In this calculation mode the function blockMax Interf Signal (Df) that you entered represents the absolute power level (in dBm) of maximum interfering signal (maximum acceptable interfering power), which might be tolerated by the receiver at a given frequency separation (see Figure 12).
In this case SEAMCAT calculates the receiver attenuation, Attenuation (Df), to be applied to the interfering signal by using the following expression:
Attenuation(Df) = blockMax Interf Signal (Df) (dBm) - sensVLR (dBm) + C/(N+I) (dB) – I/N (dB) (Eq. 23)
where:
- Df = (fILT - fVLR) is the frequency separation;
- sensVLR is the sensitivity of the VLR (dBm) as defined in the simulation scenario.
To achieve a realistic value, you may define the sensitivity (sensVLR) as (see the figure below):
Sensitivity = Noise Floor + C/(N+I)
Sensitivity = -110 dBm + 16 = -94 dBm
Figure 103: Setting up the sensitivity in SEAMCAT
Then the attenuation may be evaluated:
Attenuation (Df ) = 40 + 94 + 16 - 0 = 150 dB
iRSSblocking = Interfering Signal Level (f it )= -54.5 - 150 = -204.5 dBm
This can be checked by running a simulation and displaying the iRSSblocking in case of Sensitivity mode calculated by SEAMCAT see Figure 104.
Figure 104: Mean iRSSblocking in case of Sensitivity mode