US 7,548,120 B2 · Frequency switching method

Abstract

A frequency switching method is used to make switching among a plurality of frequency signal sources each providing a specific frequency range covering multiple bands. The method includes steps of providing a target frequency data; selecting one of the frequency signal sources to output a first clock signal; generating a first frequency data according to the clock signal of the first frequency to compare with the target frequency data; outputting a second clock signal with the highest band of another one of the frequency signal sources possessing a frequency range higher than that of the selected frequency signal source when the target frequency data is greater than the first frequency data; and outputting the second clock signal with the lowest band of the selected frequency signal source when the target frequency data is smaller than the first frequency data.

Claims18

Dependent claims

A frequency switching method for switching among a plurality of frequency signal sources, each frequency signal source providing a predetermined frequency range with multiple bands, the method comprising steps of:

a) providing a target frequency data;
b) selecting a first frequency signal source among the frequency signal sources operating to generate a first clock signal;
c) generating a first frequency data according to the first clock signal to compare with the target frequency data;
d) operating the first frequency signal source at the lowest band to generate a second clock signal when the target frequency data is smaller than the first frequency data;
and
e) switching to a second frequency signal source among the frequency signal sources when the target frequency data is greater than the first frequency data, wherein the second frequency signal source possesses a frequency range higher than that of the first frequency signal source and operating at the highest band thereof to generate the second clock signal.

3 more elements

A frequency switching method for switching among a plurality of frequency signal sources, each frequency signal source providing a specific frequency range with multiple bands, the method comprising steps of:

a) providing a target frequency data;
b) selecting a first frequency signal source among the frequency signal sources operating to generate a first clock signal;
c) generating a first frequency data according to the first clock signal to compare with the target frequency data;
d) operating the first frequency signal source at the highest band thereof to generate a second clock signal when the target frequency data is greater than the first frequency data;
and
e) switching to a second frequency signal source among the frequency signal sources when the target frequency data is smaller than the first frequency data, wherein the second frequency signal source possesses a frequency range lower than that of the first frequency signal source and operates at the lowest band thereof, to generate the second clock signal.

3 more elements

Dependencies are inferred from the claim text.

Frequency switching method

Life of this patent

Frequency switching method

Life of this patent

Abstract

Claims18