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# SPECTRAN V6 100% POI at different FFT rates

The SPECTRAN V6 advanced processing architecture combined with its 245MHz analysis bandwidth (RSA500X or RSA2000X with 245MHz RTBW option) provides a 100% POI (Probability Of Intercept) for signals with durations as short as 49ns.

The POI thow highly depends on the used FFT and is calculated as FFT/sampling rate. But since we need at least a second FFT with 50% overlapping for a 100% POI our total FFT time will also increase by 50%.

The following table at different FFTs will make it more clear:

• FFT of 8 @245MHz = 8/245Mio * 1,5 = 49ns 100% POI
• FFT of 16 @245MHz = 16/245Mio * 1,5 = 98ns 100% POI
• FFT of 32 @245MHz = 32/245Mio * 1,5 = 196ns 100% POI
• FFT of 64 @245MHz = 64/245Mio * 1,5 = 392ns 100% POI
• FFT of 128 @245MHz = 128/245Mio * 1,5 = 784ns 100% POI
• FFT of 256 @245MHz = 256/245Mio * 1,5 = 1,6µs 100% POI
• FFT of 512 @245MHz = 512/245Mio * 1,5 = 3,1µs 100% POI
• FFT of 1024 @245MHz = 1024/245Mio * 1,5 = 6,3µs 100% POI
• FFT of 2048 @245MHz = 2048/245Mio * 1,5 = 12,5µs 100% POI
• FFT of 4096 @245MHz = 4096/245Mio * 1,5 = 25µs 100% POI

An even lower 100% POI down to 12ns can be achieved by directly triggering on the IQ power level by using our RTSA-Suite PRO software.

Using a lower RTBW/Samplingrate e.g. the RSA250X with 80MHz RTBW would offer around 3 times higher POIs. E.g. a FFT of 8 would offer a POI of 150ns instead of 49ns with 245MHz RTBW.