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Modified Three-Level Code Acquisition Scheme for Frequency Hopping Radio in Channels with Fading

Modified three-level code acquisition scheme for frequency hopping (FH) signals, suitable for operation in a fading environment, is presented and analyzed in this letter. This scheme uses a set of passive correlators, a message demodulator and a bank of active correlators. The multiple sync prefixes reduce the probability of missing the signal in a fading environment. The effects of two the most important acquisition parameters (number of passive correlators and number of active correlators) on acquisition performances are analyzed.