| 摘要 |
PURPOSE:To always eliminate phase ambiguity by changing over a phase locked loop for continuous wave and an octal phase PSK signal reference carrier regenerating circuit in a digital multiplication type Costas loop. CONSTITUTION:An input signal is divided into two (1), and phase detectors 2a, 2b synthesize a signal with 90 deg. lead signal and a signal with unchanged phase from a branching circuit 10. Then an output of detectors 2a, 2b is inputted to identification circuits 3a-3h directly or via adders 7a, 7c, 7e, 7f and subtractors 7b, 7d. The output of each identification circuit is inputted to EX-NOR circuits 4a-4d. An output of the identification circuit 8g is ORed with an external control signal at an OR circuit 17. An output of the circuits 4a-4d is inputted to EX-OR circuits 5a, 5b and its output takes EX-NOR logic 6. The circuits 4c, 5a take NOR18 and OR19 logic with the external control signal. An output of the circuit 6 is given to an LPF 8 and a voltage controlled oscillator 9. Thus, the device is miniaturized. |
