Patent ID: 8374210

Claim:
A wide band transceiver comprising a receiver branch ( 14 ) comprising a tunable analog notch filter ( 140 ), an analog to digital converter ( 144 ) and a digital Fourier transformer ( 146 ) coupled in series; a transmitter branch ( 16 ) comprising an inverse digital Fourier transformer ( 160 ); a switchable loop-back circuit ( 12 ) coupled from the transmitter branch to an input of the notch filter; control circuitry ( 148 , 149 , 18 ) coupled from an output of the digital Fourier transformer ( 146 ) to a tuning input of the notch filter ( 140 ), the control circuitry ( 148 , 149 , 18 ) comprising a memory ( 149 a ) for storing a parameter relating an interference frequency determined from a Fourier transform produced by the Fourier transformer ( 146 ) to a control signal of the notch filter ( 140 ) when in a normal operating mode, the control circuitry ( 148 , 149 , 18 ) being configured to switch the transceiver to a calibration mode, wherein the transmitter branch ( 16 ), the loop back circuit ( 12 ) and the receiver branch ( 14 ) are simultaneously active, to determine the parameter from a response of the Fourier transformer ( 146 ) at a selected frequency position to a signal from the transmitter branch generated by the inverse digital Fourier transformer ( 160 ) with a frequency component at the selected frequency position.