Patent ID: 6181211
Filing Date: 2001-01-30
Classification: H03L

Abstract:
Method of locking the frequency of an oscillator's output signal to the frequency of a loop's input signal in a loop circuit, includinga phase comparator producing a control variable which is proportional to the phase difference between the loop's input signal and the oscillator's output signal,a controlled oscillator (55) having an output signal frequency which changes in response to the control variable which is functionally connected to a control input,characterized in that during the locking:the oscillator's control variable is attenuated essentially so that it is in the optimum range of the range of variation of the control variable,an additional control is applied to the oscillator's control input, in response to which additional control the oscillator's central frequency will change,the oscillator's central frequency is compared to a reference signal frequency,the attenuation of the oscillator's control variable is removed after the oscillator's central frequency has come sufficiently close to the reference signal frequency, andthe additional control is frozen to its value of that moment.