Frequency calibration device and method for programmable oscillator
AssigneePixart Imaging Inc.
InventorsChih Yen Wu, Chien Jung Huang, Hsiang Sheng Liu, Ching Chih Chen
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Abstract
A frequency calibration method for a programmable oscillator includes the steps of: counting an oversampling number of an oversampling signal and estimating an accumulated bit number of a USB data stream according to the oversampling signal; calculating a difference between the oversampling number and M times of the accumulated bit number when the accumulated bit number is larger than or equal to a predetermined value; and determining a frequency calibration step of the oversampling signal according to the difference. The present invention further provides a frequency calibration device for a programmable oscillator.
Claims35
A frequency calibration method for a programmable oscillator, comprising:
- receiving a clock signal and a USB data stream;
- estimating an accumulated bit number of bits between a first bit of a SYNC field and a bit immediately preceding an End-of-Packet of a data packet in the USB data stream according to the clock signal and counting an oversampling number of the clock signal;
- comparing the oversampling number and M times of the accumulated bit number when the accumulated bit number is larger than or equal to a predetermined value;
- decreasing the frequency of the clock signal when the oversampling number is larger than the M times of the accumulated bit number;
- and
- increasing the frequency of the clock signal when the oversampling number is smaller than the M times of the accumulated bit number.
A frequency calibration method for a programmable oscillator, for calibrating an oversampling signal sent from the programmable oscillator according to a USB data stream, the method comprising:
- counting an oversampling number of the oversampling signal;
- estimating an accumulated bit number of bits between a first bit of a SYNC field and a bit immediately preceding an End-of-Packet of the USB data stream according to the oversampling signal;
- calculating a difference between the oversampling number and M times of the accumulated bit number when the accumulated bit number is larger than or equal to a predetermined value;
- and
- determining a frequency calibration step of the oversampling signal according to the difference.
A frequency calibration device for a programmable oscillator, for calibrating an oscillation frequency of the programmable oscillator according to a USB data stream, the device comprising:
- a processing unit configured to count an oscillation number of the programmable oscillator, estimate an accumulated bit number of bits between a first bit of a SYNC field and a bit immediately preceding an End-of-Packet of the USB data stream according to the oscillation number, and compare the oscillation number and M times of the accumulated bit number to output a frequency calibration step;
- and
- a controller coupled to between the processing unit and the programmable oscillator and configured to calibrate the oscillation frequency of the programmable oscillator according to the frequency calibration step.
A frequency calibration method for a programmable oscillator, comprising:
- receiving a clock signal and a USB data stream;
- counting an oversampling number of the clock signal;
- estimating a bit number between adjacent transition edges according to the oversampling number corresponding to the adjacent transition edges in the USB data stream and accumulating the bit number between consecutive adjacent transition edges to obtain an accumulated bit number;
- comparing the oversampling number and M times of the accumulated bit number when the accumulated bit number is larger than or equal to a predetermined value;
- decreasing the frequency of the clock signal when the oversampling number is larger than the M times of the accumulated bit number;
- and
- increasing the frequency of the clock signal when the oversampling number is smaller than the M times of the accumulated bit number.
A frequency calibration method for a programmable oscillator, for calibrating an oversampling signal sent from the programmable oscillator according to a USB data stream, the method comprising:
- counting an oversampling number of the oversampling signal;
- estimating a bit number between adjacent transition edges according to the oversampling number corresponding to the adjacent transition edges in the USB data stream and accumulating the bit number between consecutive adjacent transition edges to obtain an accumulated bit number;
- calculating a difference between the oversampling number and M times of the accumulated bit number when the accumulated bit number is larger than or equal to a predetermined value;
- and
- determining a frequency calibration step of the oversampling signal according to the difference.
A frequency calibration device for a programmable oscillator, for calibrating an oscillation frequency of the programmable oscillator according to a USB data stream, the device comprising:
- a processing unit configured to count an oscillation number of the programmable oscillator, estimate a bit number between adjacent transition edges according to the oscillation number corresponding to the adjacent transition edges in the USB data stream, and accumulate the bit number between consecutive adjacent transition edges to obtain an accumulated bit number and comparing the oscillation number and M times of the accumulated bit number to output a frequency calibration step;
- and
- a controller coupled to between the processing unit and the programmable oscillator and configured to calibrate the oscillation frequency of the programmable oscillator according to the frequency calibration step.
Dependencies are inferred from the claim text.