A civil moderate (CM) code and a civil long (CL) code are time division multiplex (TDM) as a combined code having alternating code chips that spectrum spread a transmitted signal received by a receiver tracking the spectrum spreading code using a two-level correlator operating with +1 and -1 values to alternately correlate the received CM and CL code chips using a gating signal to gate by time the correlation of the two codes. The time gated two-level TDM correlation can be used in communication receivers, such as GPS receivers, receiving the TDM spectrum spreading codes.
Keywords: multiplexed, spectrum, correlator
International Class: H04B1/69, H03D1/02, H04B1/707, H04B7/212, G01S1/00