| 摘要 |
PURPOSE:To implement spread spectrum communication by means of a simple equipment. CONSTITUTION:At first a sender side implements spread spectrum processing by using a spread code synchronously with a carrier. The signal subject to spread spectrum processing is received by a receiver side and inputted to a comparator 72, where the waveform is shaped and a carrier modulated by the spread code is extracted. The signal and its inverting signal are given to 1st and 2nd counters 76a, b, in which the period is counted and a long wavelength in the signal is detected. The long wavelength part depends on the rising or trailing of the spread code and the leading and trailing timing of the spread code is detected by 1st and 2nd coincidence discrimination circuits 78a, b. Then the state of the 1st and 2nd flip-flop circuits 80a, b is changed by the output of the 1st and 2nd coincidence discrimination circuits 78a, b and the coincidence of the state is discriminated by a 3rd coincidence discrimination circuit 82, then the spread code is detected. |
