Code shift keying (CSK) apparatus and method for spectrum spread communication

摘要

In a Code Shift Keying (CSK) communication method and apparatus on the signal transmitting side, two Manchester M series equal in code length are produced with a predetermined period. The Manchester M series to actually be transmitted has a maximum value of the absolute value of its autocorrelation which is always larger than that of the cross-correlation of the two Manchester M series. In every predetermined period, one of the two series is selected; the selection depends on whether the transmitting data is "1" or "0", so that the selected series is transmitted as a transmitting signal. On the signal receiving side, a receiving signal is compared with each of two Manchester M series which are the same as those on the signal transmitting side, to provide two correlation outputs. The correlation outputs are subjected to comparison, and the receiving data "0" or "1" is selected according to the result of comparison.