| 摘要 |
PURPOSE:To improve the reception S/N and to enhance the accuracy by using a signal applying spread spectrum of a signal of a transmission carrier so as to apply communication thereby making the reception band narrow. CONSTITUTION:An ON/OFF keying signal outputted from a signal generating circuit 11 is logical 1, then a transistor(TR) 12 is turned on, an active element 13 is operated to oscillate a carrier of 300MHz. The carrier is multiplied with a spread code from a spread code generating circuit 20 in a spreading circuit 21, in which spectrum is spread. An output of the circuit 21 is amplified by a transmission circuit TX and sent to an antenna 23. The transmission signal is received by a receiver 30, a tuning circuit 32 receives two line spectrums, they are amplified by a transistor(TR) 36 and detected by a diode 39. The rectified output is smoothed by a capacitor 41 and compared with a voltage of a reference voltage source 45 at a comparator 44 and an H level signal is outputted. |
