The present invention relates to an apparatus and a method for generating
wanted previous PN states using a clock signal once. More specifically,
the apparatus includes a PN code generator for generating current PN
states composed of current PN state values that are outputted from each
end of N shift registers; an expanded PN code generator for generating
N-1 previous state values of the shift register using the current state
values; and a means for outputting time-shifted PN states by operating
the current state values and the N-1 previous state values together with
a PN mask value, thereby shortening a great amount of time required to
generate the previous PN states.
