Necessary BW calculation

0209-EX-ST-2011 Text Documents

General Atomics Aeronautical Systems

2011-04-06ELS_114800

Necessary Bandwidth Description
The Necessary BW is estimated based on calculation. The calculations are based on Table A in Annex J of the NTIA
manual for phase coded pulsed radar (including spread spectrum)
The calculation is based whether t/tr < 12.6 where
t is the waveform length, for our case the shortest expected pulse length of 0.2 Microsecond
tr is the rise time of the pulse expected to be < 0.01 Microsecond
Therefore
t/tr= .2/.01=20 > 12.6
Therefore
Bn = B(−20dB) = 6.36/t =6.36 /.2 = 31.8 MHz

Note some version of the NTIA manual shows the equation as 6.36/sqrt(t), let us know if we need to change to
that version.
Although the system is will be frequency hopping from 9.3-9.5 GHz, note 7 mentions that necessary bandwidth is
the instantaneous bandwidth of one of the channels

Document Created: 2011-04-06 17:54:04
Document Modified: 2011-04-06 17:54:04

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