In this paper, we theoretically analyse the influence of intersymbol interference (ISI) and continuous wave interference (CWI) on the bit error rate (BER) performance of the spread spectrum (SS) system using a real-valued Human sequence under the additive white Gaussian noise (AWGN) environment. The aperiodic correlation function of the Human sequence has zero sidelobes except the shift-end values at the left and right ends of shift. 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 the bit duration T = NTc, N = 2n, n = 1
2
from the sequence of length M = 2kN + 1, k = 0
1
, where Tc is the chip duration and N is the spreading factor. As a result, the BER performance of the system is improved with decrease in the absolute value of the shift-end value, and is not influenced by ISI if the shift-end value is almost zero-value. In addition, the BER performance of the system of the bit duration T = NTc with CWI is improved with increase in the sequence length M = 2kN + 1, and the system can decrease the influence of CWI.