Patent ID: 8345808

Claim:
A computational method for narrow-band interference detection based on discrete signal processing in a radio frequency receiver, the method comprising: initially estimating, via a first autocorrelation function (ACF) unit, a narrow-band interference frequency in a narrow-band interference frequency detector using a first stage of a multi-stage autocorrelation-function applied to an input signal; estimating, via a second ACF unit, at least one residue frequency based on at least one other autocorrelation stage of the multi-stage autocorrelation-function, the input signal and the initial frequency estimate; and combining the results of multiple stages of the multi-stage autocorrelation-function for final estimation, wherein the final estimation produces an estimate of the narrow-band interference frequency based on the combined results of the multi-stage autocorrelation-function, the initial frequency estimate of the first autocorrelation stage is computationally expressed as f ^ i , 1 = 1 2 ⁢ π ⁢ ⁢ T ⁢ arg ⁢ { ACF ⁡ ( m ; M , 1 ) } wherein arg{ACF (m; M,1)} is the angular function that returns the angle of a complex number, and wherein ACF(m;M,1) is the autocorrelation function (ACF) defined as ACF ⁡ ( m ; M , 1 ) = ∑ l = 0 M - 1 ⁢ R ⁡ ( m + l ) ⁢ R * ⁡ ( m + l + 1 ) where R(m+l) is a discrete received signal R at time instant m+l, m being an index of a first sample in a first segment, and l being an offset index; ( )* denotes a conjugation operator; and M is summation window size of the ACF.