| 摘要 |
PURPOSE:To embody a simple circuitry as compared with a conventional active correlation and a synchronizing capture which is low cost and high speed. CONSTITUTION:A received spreaded spectrum signal is inversely spread in a mixer 38. The correlation pulse width of the inverse spread output corresponds to the frequency error of the carrier wave of the spreaded spectrum signal and the reference frequency. At first, the loop switch SW2 of a PLL loop 48 is opened, offset voltage is imparted to WCO 32 so that the correlation pulse width of the inverse spread output may be long and the oscillation frequency is controlled. When it is detected that the frequency error becomes small by the correlation pulse width and the PLL loop 48 can be drawn to a lock state, the timing that the phases of a reception side for inverse spread PN code and the transmission side PN code of the spread spectrum signal roughtly coincide is detected by a correlation pulse, the loop switch SW2 of the PLL loop 48 is turned on and a synchronizing capture is performed. |
