Wireless Modem Data Pump
FX909A
Figure 13 Interleaving - Input/Output
1.5.5.4
Scrambling
All formatted bits of a Mobitex Data Block are passed through a 9-bit scrambler. This scrambler is
initialised at the beginning of the first Data Block in every Frame. The 511-bit sequence is generated
with a 9-bit shift register with the output of the 5th and 9th stages XOR'ed and fed back to the input of
the first stage. The scrambler is disabled during all other tasks, apart for TSO.
ã 1996 Consumer Microcircuits Limited
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D/909A/4