| 摘要 |
PURPOSE:To attain high speed processing suitable for a burst receiving wave by making respectively the best of features of the inverse modulating system and the base band costas loop system to constitute a demodulating system. CONSTITUTION:A 4-phase PSK modulated wave signal is multiplied by 2 at a 2- multiplication circuit 1 and converted into a form of a 2-phase PSK modulated signal. A signal after conversion is applied to a mixer 4 and the signal is subjected to inverse modulation by an output signal of a base band signal producing circuit 3. The inversely modulated signal passes through a filter 5, where only a desired signal component cos2omegact is extracted and a true carrier wave component cosomegact is extracted by a 1/2 frequency divider. Then, the carrier wave is applied to a regenerated data extracting circuit 2 in order to demodulate the 4-phase PSK wave. The extracting circuit 2 forms the components of sinomegact and cosomegact based on this carrier wave and applied them to demodulators 8-1 and 8-2 respectively. |
