| 摘要 |
PURPOSE:To lessen the S/N deterioration caused by the multiplier by dividing into two parts the output of the mixer which mixes the output between the phase transition circuit and the double-multiplication circuit via the output of the band limit filter and then eliminating the phase indeterminacy of the reproduced carrier. CONSTITUTION:The double 2-phase modulation wave sent from input terminal 3 with band limit applied is given to double-multiplier 21 to generate the signal featuring both the bright line spectrum and the continous spectrum. And this signal is applied to one side of mixer 22. At the same time, the clock signal applied to terminal 5 is applied to the other side input terminal of mixer 22 through phase transistion unit 23. Thus the bright line spectrum of double carrier frequency is generated to the output mixer 22 to be applied to carrier synchronous circuit 101. The noise component is removed through filter 24 provided to circuit 101, and the undesired amplitude component is eliminated through amplitude limiter 25 for the signal the noise of which is removed. This signal is then applied to 1/2 divider 26 for the frequency division, thus delivering the reproduced carrier to output terminal 4. |
