| 摘要 |
PURPOSE:To provide a demodulating device whereby VCO synchronization pull-in time inside a carrier wave reproducing part in the demodulating device used for satellite communication is shortened. CONSTITUTION:An AGC amplifying part 1 amplifying the input signal of an SCPC system to a certain output level, a demodulating part 2 demodulating the output of the AGC amplifying part and outputting first, second and third branching signals, a comparing part 4 wave-detecting the first branching signal and applying a control voltage in difference from a reference value, a carrier wave reproducing part 5 having VCO which outputs a carrier wave signal from the second branching signal and a synchronization judging part 7 counting an error number from demodulation data of the third branching signal and judging whether it is non-synchronizing or synchronizing by whether a value is larger or smaller than a prescribed threshold value are provided so that the carrier wave reproducing part stores a level where the control voltage to the AGC amplifying part becomes min. and the sweep of VCO is executed within the + or - level range restricted from the min. level. |
