Method of frequency search for DCO and decoder using the same
AssigneeMediatek Inc.
InventorHsiang-Hui Chang
Life of this patent
Estimating the term…
Abstract
A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands. The method comprises providing multiple workable pre-control codes, each control code comprising a most significant bit (MSB), corresponding to each frequency of the DCO for selection, selecting one of the workable pre-control codes according to the MSBs thereof, and providing the selected control code to the DCO.
Claims24
A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands, the method comprising:
- dividing an output signal received from a loop filter to generate multiple workable pre-control codes corresponding to a frequency of the DCO for selection, wherein each pre-control code comprises a most significant bit (MSB);
- selecting one of the workable pre-control codes according to the MSBs thereof;
- and
- providing the selected pre-control code to the DCO.
A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands each corresponding to a first predetermined number of delay units, comprising:
- dividing an output signal of a filter by a second predetermined number, wherein the second predetermined number is half of the first predetermined number;
- providing a quotient of the division and an integral part of a remainder of the division as first and second parts of a first workable pre-control code respectively;
- generating a first part of a second workable pre-control code by subtracting the first part of the first second workable pre-control code by one;
- generating a second part of the second workable pre-control code by adding the second part of the first second workable pre-control code by the second predetermined number;
- selecting one of the workable pre-control codes according to the first parts thereof;
- and
- providing the selected pre-control code to the DCO.
A method of frequency search for a digitally controlled oscillator (DCO) with overlapped sub-bands each corresponding to a first predetermined number of delay units, comprising:
- dividing an output signal of a filter by a second predetermined number, wherein the second predetermined number is half of the first predetermined number;
- providing a quotient of the division and an integral part of a remainder of the division as first and second parts of a first workable pre-control code respectively;
- generating a first part of a second workable pre-control code by adding the first part of the first second workable pre-control code by one;
- generating a second part of the second workable pre-control code by subtracting the second part of the first second workable pre-control code by the second predetermined number;
- selecting one of the workable pre-control codes according to the first parts thereof;
- and
- providing the selected pre-control code to the DCO.
A decoder providing a control code for a digitally controlled oscillator (DCO) with multiple sub-bands, the decoder comprising:
- a first pre-control code generator dividing an output signal received from a loop filter to generate a first pre-control code comprising first and second parts;
- a second pre-control code generator generating a second pre-control code comprising first and second parts according to an output of the first pre-control code generator;
- a comparator receiving the first parts of the first and second pre-control codes and generating a control signal;
- and
- a multiplexer receiving the first and second parts of the first and second pre-control codes and selecting one of the same as the control code according to the control signal.
A decoder providing a control code for a digitally controlled oscillator (DCO) with multiple sub-bands, the decoder comprising:
- a first pre-control code generator arranged to receive an output signal of a filter and divide the output signal to generate a first pre-control code;
- a second pre-control code generator arranged to receive the first pre-control code of the first pre-control code generator;
- a comparator coupled to the first and second pre-control code generators;
- and
- a multiplexer coupled to the comparator.
A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands, comprising:
- dividing a current output signal of a filter to generate first and second workable pre-control codes at different frequency search paths for selection, respectively, wherein periods of the DCO set by the first and second workable pre-control codes are the almost same;
- selecting one of the first and second workable pre-control codes according to a previous output signal of the filter;
- and
- providing the selected pre-control code to the DCO.
A method of frequency search for a digitally controlled oscillator (DCO) with multiple sub-bands, comprising:
- dividing a current output signal of a loop filter to determine first and second frequency search paths for a frequency of the DCO;
- selecting one of the first and second frequency search paths according to a previous frequency search path based on a previous output signal of the filter;
- and
- controlling the frequency of the DCO according to the selected frequency search path.
Dependencies are inferred from the claim text.