Patent ID: 7650118

Claim:
A wireless transmission system comprising a wireless transmission apparatus for sending radio signals in a selected frequency and a wireless reception apparatus for receiving the radio signals in the selected frequency and playing audio signals corresponding to the radio signals, wherein: the wireless transmission apparatus comprises: a scan unit for periodically scanning interference frequencies of candidate frequencies which are selectable as a transmission frequency, and recording characteristics of each said interference frequency; an evaluation value calculating module for calculating an evaluation value of each said candidate frequency according to the characteristics of the corresponding interference frequencies; a frequency selection module for choosing one of the candidate frequencies as a current transmission frequency according to the evaluation values; and a transmission unit for sending radio signals in the current transmission frequency; wherein the characteristics of the interference frequency comprise a signal level and a frequency thereof, and the evaluation value calculating module calculates the evaluation value according to an equation P=ΣQ=Σ((V n′t +ΔV 2 )/D 2 ), in which V n′t represents a signal level of an n'th interference frequency in a current scan period t, ΔV represents a level difference between a signal level V n′t in the current scan period t and a signal level V n′(t-1) in the immediately preceding scan period t−1, and D represents a frequency difference between the interference frequency and the candidate frequency.