Frequency detector for measuring and tuning frequency of controlled oscillator

A frequency detector for measuring and tuning a frequency of a controlled oscillator comprising:

• a pulse generator for generating sampling pulses;
• a multi-stage frequency divider connected to the output of the controlled oscillator;
• a sample circuitry for sampling output states from each stage of the divider;
• and
• a digital processing unit;
• wherein the sample circuitry is configured to sub-sample the output states of the divider at a sampling frequency lower than the frequency of the controlled oscillator;
• and
• the digital processing unit is configured to calculate a frequency offset of the controlled oscillator based on the sampled output states and generate a control signal based on the frequency offset to tune the frequency of the controlled oscillator.

A method for measuring and tuning a frequency of a controlled oscillator comprising:

• sub-sampling states of the controlled oscillator at a sampling frequency lower than the frequency of the controlled oscillator;
• calculating a state difference between pairs of adjacent sampled states;
• estimating a frequency offset based on the state differences;
• generating a control signal based on the frequency offset;
• and
• tuning the frequency of the controlled oscillator based on the control signal.