Operating a phase locked loop

A phase locked loop comprising:

• means for generating an alternating-current output signal having a frequency which depends on an applied control voltage;
• means for providing a control voltage to said means for generating an alternating-current output signal, said control voltage reflecting determined phase differences between a potentially frequency divided output signal of said means for generating an alternating-current output signal and a reference signal;
• means for detecting frequency deviations between said potentially frequency divided output signal of said means for generating an alternating-current output signal and a reference signal, wherein a resolution employed for detecting said frequency deviations is lower than a resolution employed for determining said phase differences;
• and
• means for adding a direct-current voltage shift to said control voltage provided by said means for providing a control voltage, in case a frequency deviation is detected by said means for detecting frequency deviations.

A phase locked loop comprising:

• a voltage controlled oscillator adapted to generate an alternating-current output signal having a frequency which depends on an applied control voltage;
• a loop filter adapted to provide said control voltage to said voltage controlled oscillator, said control voltage reflecting determined phase differences between a potentially frequency divided output signal of said voltage controlled oscillator and a reference signal;
• and
• a coarse tuning circuit adapted to detect frequency deviations between said potentially frequency divided output signal of said voltage controlled oscillator and said reference signal, wherein a resolution employed for detecting said frequency deviations is lower than a resolution employed for determining said phase differences, and adapted to add a direct-current voltage shift to said control voltage provided by said loop filter, in case a frequency deviation is detected.

A mobile electronic device comprising a phase locked loop with:

• a voltage controlled oscillator adapted to generate an alternating-current output signal having a frequency which depends on an applied control voltage;
• a loop filter adapted to provide said control voltage to said voltage controlled oscillator, said control voltage reflecting determined phase differences between a potentially frequency divided output signal of said voltage controlled oscillator and a reference signal;
• and
• a coarse tuning circuit adapted to detect frequency deviations between said potentially frequency divided output signal of said voltage controlled oscillator and said reference signal, wherein a resolution employed for detecting said frequency deviations is lower than a resolution employed for determining said phase differences, and adapted to add a direct-current voltage shift to said control voltage provided by said loop filter, in case a frequency deviation is detected.

A communication system comprising an electronic device, which electronic device includes a phase locked loop with:

• a voltage controlled oscillator adapted to generate an alternating-current output signal having a frequency which depends on an applied control voltage;
• a loop filter adapted to provide said control voltage to said voltage controlled oscillator, said control voltage reflecting determined phase differences between a potentially frequency divided output signal of said voltage controlled oscillator and a reference signal;
• and
• a coarse tuning circuit adapted to detect frequency deviations between said, potentially frequency divided output signal of said voltage controlled oscillator and said reference signal, wherein a resolution employed for detecting said frequency deviations is lower than a resolution employed for determining said phase differences, and adapted to add a direct-current voltage shift to said control voltage provided by said loop filter, in case a frequency deviation is detected.