GMSK Packet Data Modem and RF Transceiver
CMX990
Figure 18 Interleaving - Input/Output
5.1.5.4 Scrambling
All formatted bits of both Mobitex Data Blocks and Short Data Blocks are XORed with the
output of 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 2004 CML Microsystems Plc
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