Frequency calibration circuit for automatically calibrating frequency and method thereof
AssigneeEtron Technology, Inc.
InventorsHuan-Hsiang Shen, Chih-Kao Chen, Chien-Cheng Kuo
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Abstract
A serial interface engine generates a series of digital data according to a pair of differential signals received from a high-speed Universal Serial Bus host and/or a full-speed universal serial bus host. Then, a packet identification (PID) unit identifies a packet identification of a start of each frame and a first period between two consecutive packet identifications according to the series of digital data. A count comparator is used for generating a calibration signal to calibrate an output frequency of an oscillator according to the first period.
Claims13
A method for automatically calibrating frequency, the method comprising:
- generating a series of digital data according to a pair of differential signals received from a high-speed Universal Serial Bus (USB) host and/or a full-speed Universal Serial Bus (USB) host;
- identifying a packet identification (PID) of a start of each frame according to the series of digital data;
- and
- calibrating an output frequency of an oscillator according to a first period between two consecutive packet identifications.
A frequency calibration circuit for automatically calibrating frequency, the frequency calibration circuit comprising:
- a serial interface engine for generating a series of digital data according to a pair of differential signals received from a high-speed Universal Serial Bus (USB) host and/or a full-speed Universal Serial Bus (USB) host;
- a packet identification unit for identifying a packet identification (PID) of a start of each frame and a first period between two consecutive packet identifications according to the series of digital data;
- an oscillator;
- and
- a count comparator for generating a calibration signal to calibrate an output frequency of the oscillator according to the first period.
Dependencies are inferred from the claim text.