| 摘要 |
PURPOSE:To attain narrow-band and constant-amplitude efficient transmission by performing Nyquist waveform transmission by providing PLL circuits to transmission and reception parts and a bit integrating circuit to the reception side. CONSTITUTION:On a transmission side and reception, PLLs are composed of phase detectors 12 and 15, loop filters 13 and 16, and VCOs 14 and 17, and on the reception side, bit integrating circuit 19, etc., are added. In this constitution, transfer characteristic FT(s) of filter 13 are represented by closed-loop transfer function HT(s)=thetaOT/thetaiT denoting constants of detector 12 and VCO14 by KDT and KOT respectively. Here, thetaiT and thetaoT are phase characteristics of respective parts. As to the reception side, HR(s)=thetaoR/thetaiR is obtained similarly. Next, output VI of filter 16 is passed through phase equalizer 18 and circuit 19 to obtain output V2=ETAT(s). HR(s).HE(s).thetaiT/KoR. Here, amplitude characteristics are made to approximate by a rational function to obtain transfer characteristics FT and FR, which are mixed by a circuit, so that the overall characteristics will satisfy the 1st Nyquist postulate. |
