Frequency detection for over-the-air calibration of oscillators
AssigneeWiliot, Ltd.
InventorsNir SHAPIRA, Shay KOREN
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Abstract
An oscillator calibration circuit is provided. The oscillator calibration circuit includes a signal frequency detector for producing a reference signal from a received over-the-air signal detecting a frequency of the over-the-air signal; and a first frequency locking circuit (FLC) coupled to the signal frequency detector and to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using the reference signal to a radio frequency (RF) carrier frequency, wherein the reference signal is utilized for calibrating the first oscillator based on the frequency of the detected over-the-air signal.
Claims20
An oscillator calibration circuit, comprising:
- a signal frequency detector for producing a reference signal from a received over-the-air signal detecting a frequency of the over-the-air signal;
- and
- a first frequency locking circuit (FLC) coupled to the signal frequency detector and to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using the reference signal to a radio frequency (RF) carrier frequency, wherein the reference signal is utilized for calibrating the first oscillator based on the frequency of the detected over-the-air signal.
The oscillator calibration circuit, wherein the signal frequency detector further comprises:
- an auxiliary oscillator;
- and
- a counter coupled to the auxiliary oscillator, wherein the counter measures a frequency of the auxiliary oscillator relative to the over-the-air signal.
The oscillator calibration circuit of 1, wherein the signal frequency detector is further configured to:
- compare the frequency measurement to a predefined lower limit and upper limit;
- and
- determine the frequency of the over-the-air signal based on the comparison.
The oscillator calibration circuit of 1, wherein the signal frequency detector is further configured to detect the frequency based on at least two over-the-air signals, wherein the two over-the-air signals are of different frequencies.
The oscillator calibration circuit of 5, wherein the signal frequency detector is further configured to:
- receive a first over-the-air signal;
- detect a frequency of the first over-the-air signal produced from the first over-the-air signal;
- receive a second over-the-air signal;
- detect a frequency of the second over-the-air signal produced from the first over-the-air signal;
- determine a ratio between the frequency of the first refence signal and the frequency of the second reference signal;
- and
- based on the ratio, determine the frequencies of the first and second reference signals and the first and second over-the-air signals.
The oscillator calibration circuit of 6, wherein the calibration of the first oscillator is aborted when the determined ratio is substantially equal to 1.
A wireless transmitter, comprising:
- an antenna;
- an oscillator calibration circuit coupled to the antenna, wherein the oscillator calibration circuit comprises:
- a signal frequency detector for producing a reference signal from a received over-the-air signal and detecting a frequency of the over-the-air signal;
- and
- a first frequency locking circuit (FLC) coupled to the signal frequency detector and to a first oscillator, wherein the first FLC calibrates the frequency of the first oscillator using the reference signal to a radio frequency (RF) carrier frequency, wherein the reference signal is utilized for calibrating the first oscillator based on the frequency of the detected over-the-air signal.
Dependencies are inferred from the claim text.