Method and apparatus of locating channels in a frequency band

A method for locating a channel in a frequency band, comprising:

• (a) setting an initial frequency and a first frequency step, determining a frequency point based on the initial frequency and the first frequency step, and checking whether the frequency point satisfies a first condition which is continuously detecting a horizontal signal a predetermined number of times;
• (b) when the first condition is satisfied, recording the frequency point as an entrance point, and when the first condition is not satisfied, updating the frequency of the frequency point according to the first frequency step, and going to step (a);
• (c) based on the entrance point, a second frequency step and a frequency control signal, determining a second frequency point, wherein the second frequency step is less than the first frequency step, and checking whether the second frequency point satisfies a second condition which is continuously detecting a vertical signal or the horizontal signal the predetermined number of times;
• (d) when the second condition is satisfied, determining whether a gap between the second frequency point and a target frequency is less than a first frequency gap;
• (e) when the second condition is not satisfied, updating the initial frequency to be the frequency of the entrance point;
• (f) if the gap determined in step (d) between the second frequency point and target frequency is less than the first frequency gap, recording that a television channel exists at the second frequency point;
• and
• (g) repeating steps (a)-(f) through the frequency band.