Carrier regeneration circuit including area judging device
Patent 5594389 Issued on January 14, 1997. Estimated Expiration Date: 
November 30, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 30, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesQAM Demodulator carrier recovery loop using n-m LSB's Demodulator with AGC circuit for multi-level quadrature amplitude-modulated carrier wave Method and apparatus for recovering a qam carrier Patent #: 5519733 InventorsAssigneeApplicationNo. 565732 filed on 11/30/1995US Classes:331/12, With phase-shifted inputs329/309, Including logic element (e.g., logic gate or flip-flop)331/17, Particular error voltage control (e.g., intergrating network)375/326, Carrier recovery circuit or carrier tracking375/327, Phase locked loop375/376Phase locked loopExaminersPrimary: Grimm, Siegfried H.International ClassesH03L 007/085H04L 027/38 Foreign Application Priority Data1995-03-20 JPAbstractA carrier regeneration circuit achieves quick frequency synchronization without using a sweeper. An area judging device judges whether a baseband signal, quadrature-demodulated with a regenerated carrier output from a voltage-controlled oscillator, lies inside a designated area in a phase plane. If it is inside the designated area, an output of a phase comparator is selected, and if it has exited the area, the previous value is held. The designated area is set so that the direction of control indicated by the phase comparator, just before the baseband signal rotating in the phase plane exits the area, coincides with a direction that suppresses the rotation.Field of SearchPlural comparators or discriminatorsWith phase-shifted inputs Particular error voltage control (e.g., intergrating network) With parallel signal combiners (e.g., Costas loop) Including logic element (e.g., logic gate or flip-flop) Phase locked loop Carrier recovery circuit or carrier tracking Phase locked loop | |
