PHASE LOCKED LOOP CIRCUIT AND SIGNAL RECOVERY CIRCUIT USING IT

摘要

PROBLEM TO BE SOLVED: To incorporate a loop filter in an LSI in the PLL circuit having a digital phase comparator. SOLUTION: A 1st D/A converter 106 and a digital integration device 12 are connected to an output of a digital phase comparator 103, a 2nd D/A converter 107 is connected to the digital integration device 12 and a current controlled oscillator 109 is controlled by analog currents from the 1st and 2nd D/A converters 106, 107 to configure basically the PLL circuit. Then an oscillated output from the current controlled oscillator 109 is fed back to one input of the digital phase comparator 103 and a reference signal is fed to the other input of the digital phase comparator 103.