| 摘要 |
PURPOSE:To improve endurability against disturbance and noise resistance, by modulating information data or voice signals with modulating circuits having different frequencies on a modulating side, executing an adding arrangement and, further, a spreading of spectrum and, on a demodulating side, adding plural signals obtained by carrying out reverse spreading and demodulating a spread spectrum signal. CONSTITUTION:Plural two-phase PSK(Phase Shift Keying) signals are prepared to one piece of information data 1, arranged closely so as not to interfere with one another, spread it with one spreading code by means of a clock signal frequency for spreading code set 10 beforehand and the period length of the spreading code, and a spreading of spectrum is executed while maintaining a condition in which they do not spectrally interfere. At the time of demodulating, plural two-phase PSK signals in an reverse spreading 23 are detected 28 and 29, added and outputted 35 respectively. Thus, though the information data is increased by the added, the noise component is added as a square root, and consequently, S/N can be improved. |
