| 摘要 |
<p>PURPOSE:To improve the transmission quality by compressing the level of a modulation input signal to apply SSB modulation, sending the result while a carrier signal is added, applying amplitude limit to a reception signal, detecting the signal, and applying level expansion so as to restore the signal thereby reducing audible noise. CONSTITUTION:An information signal such as a modulation signal inputted to a modulation signal input terminal 1 of a sending section 8 is inputted to a level compressor 2. An SSB modulator 4 applies SSB modulation to an output of a carrier oscillator 3 by a level compression output, the SSB signal added by the carrier is obtained by an adder circuit 5 and the result is irradiated from a transmission antenna 6 by a transmitter 6. A signal received by a reception antenna 9 of a reception section 15 is inputted to an amplitude limiter 11 through a receiver 10. The output of the amplitude limiter brougnt into a prescribed amplitude is detected by a detector 12 and the detection output is led to a demodulation signal output terminal 14 through a level expander 13. Thus, audible noise is reduced to improve the quality of transmission.</p> |
