PHASE-LOCKED LOOP FREQUENCY CONTROL CIRCUIT Russian patent published in 2004 - IPC

FIELD: frequency-control circuits including those recovering normal mode of operation upon deactivation of phase-locked loop.

SUBSTANCE: proposed phase-locked loop has phase comparator, low-pass filter, frequency divider, means for detecting deactivation of phase-locked loop to check for presence or absence of comparison signal across frequency divider output or for oscillation frequency of voltage-controlled oscillator exceeding preset level; phase comparator has phase comparison unit and control means.

EFFECT: provision for return to normal mode of operation at abnormal operation of voltage-controlled oscillator.

3 cl, 9 dwg