| 摘要 |
PURPOSE:To simplify the circuit constitution by receiving a demodulation spread code signal and a 1st spread spectrum signal, applying inverse spread to the 1st spread spectrum signal by multiplication and outputting a demodulated PSK signal. CONSTITUTION:Since a delay circuit 17 is constituted to retard a sum conversion output signal Ps(t) by one time slot, the input and output sides of the delay circuit 17 are as shown in waveforms C, D. Both the signals are multiplied by a multiplier 5 and a carrier component is eliminated by an LPF 24 to detect a spread code signal P(t) equivalent at modulation as shown in (E). The spread code signal P(t) is supplied to a multiplier 4 to apply inverse spread by the multiplication with the spread spectrum signal S1(t) from an adder 18. Thus, a signal being the demodulation of the spread spectrum signal S1(t) is obtained from the multiplier 4 and an undesired frequency component is eliminated by a BPF 11 and a biphase PSK signal d(t)cosomegac1t is outputted from an output terminal Out2. Thus, the circuit is simplified. |
