| 摘要 |
<p>An m-sequence is a basic sequence used in generating PN codes for spread spectrum systems. When a signal is received the mobile unit must be able to 'jump' around in the m sequence easily so as to find the m-sequence of the transmitted signal, so the mobile unit can be synchronized. Jumping is accomplished by appending a mask to a linear feedback shift register (LFSR). A particular type of LSFR which generates an m-sequence is a Galois LFSR. When appending a mask to a Galois LFSR, a problem arises in that when jumping to a different m sequence, the first elements of the output may not be an m-sequence, (in other words the jump corrupts the output). The present disclosure provides a cascaded mask circuit for use with a Galois LFSR which prevents corruption of the m sequence during a jump. Another embodiment of an independent mask is also disclosed.</p> |
