In this paper, we evaluate the influence by a continuous wave (CW) interference on the bit error rate (BER) performance of the spread spectrum (SS) system using a real-valued Huffman sequence under the additive white Gaussian noise (AWGN) environment. The aperiodic correlation function of the sequence has zero sidelobes except at the left and right shift-ends. The system can give the unified communication and ranging system because the output of a matched filter (MF) is the ideal impulse by generating transmitted signal of period N from the sequence of length M = 2(k) N + 1, k is nonnegative integer. As a result, the BER performance of the system under the AWGN and CW interference environment is improved with increase in the sequence length M.