| 摘要 |
<p>PURPOSE:To reduce audible noises generated owing to an abrupt drop in the reception level of a received SSB modulated signal by suppressing variation in the reception level due to fading by using an amplitude limiter and performing diversity reception. CONSTITUTION:The SSB signal obtained by adding the output of an SSB modulator 3 and the output of a carrier oscillator 2 by an adding circuit 4 is transmitted through a frequency converter and amplifier 5. The received signal is inputted to amplitude limiters 14 and 15 through frequency converter and amplifiers 10 and 11 to suppress variation in reception level due to fading, etc., and led to a detection output switch 19 through detectors 16 and 17. Outputs of the frequency converter and amplifiers 10 and 11, on the other hand, are supplied to reception level detectors 12 and 13 to detect reception levels, which are compared by a switching signal generator 18 to generate a switching signal on the basis of the comparison result, so that the signal is inputted to the detection output switch 19. The detection output switch 19 selects the detection output signal of a branch having a larger reception level according to the switching signal and output it to a demodulated signal output terminal 20.</p> |
