| 摘要 |
PURPOSE:To demodulate a received signal from spread spectrum communication at high speed by providing a convolving means to take correlation between the received signal and a reference code outputted from a code generating means and a demodulating means. CONSTITUTION:The convolver 2 inputs the received signal 1 and a reference signal 3 that a carrier wave generated by an oscillator 9 is phase-modulated by a modulator 8, and when both signals coincide with each other, it generates sharp peak output. Then, a threshold is set properly fixedly or variably so that only the peak output outputted from the convolver 2 exceeds the threshold when the output of a detector 5 and the threshold set beforehand are compared by a threshold detection circuit 6. Accordingly, only when the signal 1 and the signal 3 coincide, a pulse is outputted from the circuit 6, and by inputting the pulse to a code generator 7, the timing of the reference diffused code to be generated from the generator 7 is adjusted, and synchronization between the signal 1 and the signal 3 is made. Thus, the demodulation of the received signal can be started earlier through a gate pulse generator 10, a gate circuit 11 and the demodulation circuit 16, and the received signal can be demodulated at high speed. |
