METHOD AND ARRANGEMENT FOR LOCKING A CONTROL VOLTAGE TO A VOLTAGE-CONTROLLED OSCILLATOR

摘要

To lock a control voltage to a voltage-controlled oscillator (1) in correspondence with a desired frequency (fref), a comparator (7) compares the output frequency (fvco) of the voltage-controlled oscillator (1) with the desired frequency (fref). A signal is generated in response to any frequency difference to adjust the control voltage until the frequency difference is zero. A copy of the control voltage is generated at least when said frequency difference is zero, and this generated copy is applied as control signal to the voltage-controlled oscillator (1) to lock its output frequency at the desired frequency (fref).