Crystal-free wireless devices
A crystal-free wireless device includes a frequency calibration module and a local radio frequency (RF) oscillator having a first frequency and configured to communicate with the frequency calibration module. The crystal-free wireless device also includes a relaxation ring oscillator configured to communicate with the frequency calibration module. The relaxation ring oscillator is further configured to receive a calibration signal or periodic radio frequency packets from a wireless network and provide a reference signal to the frequency calibration module. The relaxation ring oscillator is a crystal-free oscillator. The frequency calibration module is configured to generate a calibration signal that is fed back through a Frequency Locked Loop (FLL) to the local RF oscillator to calibrate the local RF oscillator. The calibrated local RF oscillator is configured to generate a clock signal.
1. A crystal-free wireless device, comprising:
a frequency calibration module;
a local radio frequency (RF) oscillator having a first frequency and configured to communicate with the frequency calibration module; and
a relaxation ring oscillator configured to communicate with the frequency calibration module, the relaxation ring oscillator being further configured to receive a calibration signal or periodic radio frequency packets from a wireless network and provide a reference signal to the frequency calibration module,
wherein the relaxation ring oscillator is a crystal-free oscillator,
wherein the frequency calibration module is configured to generate a calibration signal that is fed back through a Frequency Locked Loop (FLL) to the local RF oscillator to calibrate the local RF oscillator, and
wherein the calibrated local RF oscillator is configured to generate a clock signal.
2. The device according to claim 1 , wherein the clock signal comprises a radio clock signal.
3. The device according to claim 1 , wherein the frequency calibration module comprises a counter configured to measure a divided frequency generated by dividing the first RF frequency based on the calibration signal from the relaxation ring oscillator.
4. The device according to claim 1 , wherein the periodic RF packets are used to provide a timing reference to the frequency calibration module.
5. The device according to claim 1 , wherein the clock signal comprises a 2 MHz frequency signal for IEEE 802.15.4, a 1 MHz frequency signal for the BLE, a ADC clock signal, discrete time signal processing, or a digital baseband processor clock, or any combination thereof.
6. The device according to claim 1 , wherein the local RF oscillator has a better jitter performance than the relaxation ring oscillator for generating the clock signal.
7. The device according to claim 1 , wherein the relaxation ring oscillator comprises an RC-based oscillator.
8. The device according to claim 1 , wherein the local RF oscillator comprises an LC-based oscillator.
9. A wireless network comprising:
a plurality of nodes, one or more of the plurality of nodes being configured to generate a frequency calibration signal to calibrate a remaining plurality of nodes,
wherein the one or more of the plurality of nodes comprises:
a frequency calibration module;
a local radio frequency (RF) oscillator having a first frequency and configured to communicate with the frequency calibration module; and
a relaxation ring oscillator configured to communicate with the frequency calibration module, the relaxation ring oscillator being further configured to receive a calibration signal or periodic radio frequency packets from a wireless network and provide a reference signal to the frequency calibration module,
wherein the relaxation ring oscillator is a crystal-free oscillator,
wherein the frequency calibration module is configured to generate a calibration signal that is fed back through a Frequency Locked Loop (FLL) to the local RF oscillator to calibrate the local RF oscillator, and
wherein the calibrated local RF oscillator is configured to generate a clock signal.
10. A crystal-free wireless device, comprising:
a frequency calibration module; and
a local radio frequency (RF) oscillator having a first frequency and configured to communicate with the frequency calibration module to provide a reference signal to the frequency calibration module,
wherein the local radio frequency (RF) oscillator is a crystal-free oscillator,
wherein the frequency calibration module is configured to generate a calibration signal that is fed back to the local RF oscillator to calibrate the local RF oscillator, and
wherein the calibrated local RF oscillator is configured to generate a clock signal.