Patent ID: 8090338

Claim:
An interference cancellation system, comprising: (A) an adaptively tuned quadratic control (ATQC) module ( 200 ) for providing a tuning procedure directed to a quadratic amplitude matching filter (QAMF) ( 100 ) control function to the band of interference and for externally controlling the QAMF control function subsequent to said tuning, said adaptively tuned quadratic control (ATQC) module ( 200 ) comprising: a) an inline variable lobe filter structure (VLFS) ( 201 ) for providing controlled variable time delay for generating a broadband RF tuning filter formed by a delay T and a first narrowband inline control filter for providing a near-flat quadratic control filter lobe formed by a first delay (T) and a second delay (2nT) yielding a total time delay of (2n+1)T centered in the null of the broadband RF tuning filter and weighted by an external amplitude control signal; b) a second narrowband inline control filter as a slaved lobe filter structure-down ( 104 ) for providing a down quadratic amplitude control filter lobe formed by a delay of (2m+1)T centered in the null of the RF tuning filter and weighted by an external amplitude control signal; c) a third narrowband inline control filter as a slaved lobe filter structure-up ( 105 ) for providing a up quadratic amplitude control filter lobe formed by a simple FIR filter with inter-tap spacing delay of (2o+1)T centered in the null of the tuning filter and weighted by an external amplitude control signal; d) an offline time delay tuning control (TDTC) element ( 202 ) for receiving signal samples output from the inline variable lobe filter structure (VLFS) 201 to control a first variable time delay element (T) 205 of the inline variable lobe filter structure (VLFS) 201 to provide said controlled variable time delay to form said broadband RF tuning filter and a second variable time delay element (2nT) ( 208 ) of the inline variable lobe filter structure (VLFS) 201 to provide said controlled variable time delay to generate said slope control filter lobe; (B) an adaptive control loop ( 6 ) for adjusting a complex weighting of the delayed coupled signal ( 57 ) to maximally cancel a propagated reference signal.