| 摘要 |
<p>PURPOSE:To reduce effects due to fading and to realize the system with a simple receiver by generating a signal having an amplitude proportional to a time interval of a reception signal subjected to amplitude limit at there reception side, restoring amplitude information and applying envelope detection demodulation. CONSTITUTION:A transmission section 7 adds an output of a SSB modulator 3 and an output of a carrier oscillator 2 by using an adder circuit 4 to obtain a SSB signal added with a carrier as the output. A signal reception section 15 uses a reception antenna 8 to receive a signal, which is subjected to downconvert and amplification and the result is inputted to an amplitude limiter 10. The limiter 10 suppresses the fluctuation of a reception level caused by fading to a constant amplitude and the output of the limiter 10 is given to a sawtooth wave generating circuit 11, from which a sawtooth wave proportional to the time interval of the output of the amplitude limiter crossing the zero point is generated. An undesired wave is eliminated from the output by a band pass filter 12. The output of the band pass filter 12 is detected by an envelope detector 13 and outputted to a demodulation signal output terminal 14.</p> |
