Audio system for providing alternative frequency, vehicle having the same, and method for providing alternative frequency

An operation method of an audio system, the operation method comprising:

• setting, by a control device, a frequency of an audio device included in the audio system to a first radio frequency corresponding to a selected radio broadcast and receiving a first broadcast signal;
• receiving, by the control device, a second broadcast signal for an alternative frequency associated with the first broadcast signal with receive sensitivity of predetermined first reference sensitivity or more than the predetermined first reference sensitivity, while the first broadcast signal is received through the audio device, and verifying and storing a second radio frequency for transmitting a same broadcast as a radio broadcast of the first radio frequency based on a comparison between the first broadcast signal and the second broadcast signal;
• receiving, by the control device, a third broadcast signal for the alternative frequency, in response that the first broadcast signal with receive sensitivity less than the predetermined first reference sensitivity, but greater than or equal to predetermined reference sensitivity is received, and changing the frequency of the audio device from the first radio frequency to a third radio frequency corresponding to the alternative frequency based a comparison between the first broadcast signal and the third broadcast signal;
• and
• changing, by the control device, the frequency of the audio device based on the second radio frequency, in response that the first broadcast signal with receive sensitivity less than the predetermined second reference sensitivity is received.