| 摘要 |
PURPOSE: To provide an inexpensive demodulator with simple configuration by constituting an input transducer and transducers which generate first and second signals having correlative delay by means of a surface acoustic wave device placed on a piezo-electric substrate, a phase shift means, first and second multiplying means and deciding means. CONSTITUTION: An SAW device 100 to which a received fixed code wide band differential phase modulation data signal is supplied is provided with the input transducer 140 and output transducers 142 and 144 which are attached to the piezo-electric substrate 130. The transducers 142 and 144 generate the first and the second signals which respectively coincide with a fixed code, are correlatively replaced from the transducer 140 for the portion of distance by a prescribed mark rate and is provided with correlative delay corresponding to the period of the mark. The multiplier 110 generates the third signal by multiplying the first signal by the second signal. Moreover, the multiplier 110 multiplies the first signal by the second signal which is phase-shifted by a phase shift circuit 108 so as to generate the fourth signal. The deciding circuits 116 and 118 generate output data signals which expresse data received in response to the third and the fourth signals. |
