Code generator for multiple correlators

Abstract

A code generation apparatus that is connected to a plurality of correlation devices connected in parallel includes an initial long code (LC) state mask, initial state registers, a state buffer, local Pseudo Noise (PN) code generators, and I and Q shift registers. The initial LC state mask inputs the mask for an LC linear feedback shift register (LFSR) that is within the local PN code generators. The initial state registers input the initial contents of in-phase and quadrature LFSRs that are also within the code generators, along with the initial contents of the LC LFSR. The local PN code generators then generate ILC and QLC sequences that are input to the I and Q shift registers respectively. The shift registers, by shifting the ILC and QLC sequences, output a plurality of shifted ILC and QLC sequences to the correlation devices. The length of the ILC and QLC sequences are greater than the number of registers within the shift registers and so, in order to compare all possible shifts in the sequences, multiple passes are required. To accomplish this, the state buffer saves the contents of the LFSRs at specific times to ensure that the next pass can begin where the last left off.