A
radio system includes an audio device, and a control device operatively connected to the audio device to store a first
radio frequency of the audio device as a preset frequency, wherein the control device may be configured to determine whether a second broadcast
signal received through a second
radio frequency is equal to a first broadcast
signal received through the first
radio frequency stored in a preset
list when the second radio frequency of the audio device is added as the preset frequency, generate the preset
list including the first and second radio frequencies when the first broadcast
signal is different from the second broadcast signal, and generate the preset
list including the first or second radio frequency when the first and second broadcast signals are broadcast signals of a same radio broadcast.