Abstract: An apparatus for generating a frequency estimate of an output signal includes a reference signal generator configured to generate a reference clock signal. The apparatus includes frequency estimation circuitry configured to generate a cycle count based frequency estimation of the output signal based on the reference clock signal and a clock cycle count of the output signal. The frequency estimation circuitry further generates a fractional frequency estimation of the output signal based on the reference clock signal and a plurality of time-to-digital conversion phase samples of the output signal. The frequency estimation circuitry further generates the frequency estimate of the output signal using the cycle count based frequency estimation within a range and a frequency error determined from the fractional frequency estimation. The plurality of time-to-digital conversion phase samples and the cycle count based frequency estimation use a same number of reference clock cycles of the reference clock signal.

Abstract: An apparatus for generating an output oscillator signal is provided. The apparatus includes a deviation determining circuitry configured to generate a deviation signal based on a first comparison signal and a second comparison signal. Further, the apparatus includes a first oscillator configured to generate the output oscillator signal based on the deviation signal and a second oscillator signal from a second, resonator-based oscillator. The first comparison signal is based on the second oscillator signal or the output oscillator signal. The second oscillator signal has a frequency of at least 1 GHz. The second comparison signal is based on a third oscillator signal from a third oscillator. The third oscillator signal has a frequency lower than 1 GHz.

Abstract: An apparatus for generating a frequency estimate of an output signal includes a reference signal generator configured to generate a reference clock signal. The apparatus includes frequency estimation circuitry configured to generate a cycle count based frequency estimation of the output signal based on the reference clock signal and a clock cycle count of the output signal. The frequency estimation circuitry further generates a fractional frequency estimation of the output signal based on the reference clock signal and a plurality of time-to-digital conversion phase samples of the output signal. The frequency estimation circuitry further generates the frequency estimate of the output signal using the cycle count based frequency estimation within a range and a frequency error determined from the fractional frequency estimation. The plurality of time-to-digital conversion phase samples and the cycle count based frequency estimation use a same number of reference clock cycles of the reference clock signal.

Abstract: An apparatus for generating an output oscillator signal is provided. The apparatus includes a deviation determining circuitry configured to generate a deviation signal based on a first comparison signal and a second comparison signal. Further, the apparatus includes a first oscillator configured to generate the output oscillator signal based on the deviation signal and a second oscillator signal from a second, resonator-based oscillator. The first comparison signal is based on the second oscillator signal or the output oscillator signal. The second oscillator signal has a frequency of at least 1 GHz. The second comparison signal is based on a third oscillator signal from a third oscillator. The third oscillator signal has a frequency lower than 1 GHz.

Abstract: A frequency estimator for estimating a frequency, including a counter configured to count an integer number of full clock cycles during a measurement time window; a Time-to-Digital Converter (TDC) configured to measure a fraction of a clock cycle during the measurement time window; and a processor configured to determine the estimated frequency based on the counted number of full clock cycles and the measured fraction of the clock cycle.

Abstract: A frequency estimator for estimating a frequency, including a counter configured to count an integer number of full clock cycles during a measurement time window; a Time-to-Digital Converter (TDC) configured to measure a fraction of a clock cycle during the measurement time window; and a processor configured to determine the estimated frequency based on the counted number of full clock cycles and the measured fraction of the clock cycle.