A digital intermediate frequency unit for a radio frequency module, comprising: an obtaining subunit , configured to obtain a digital transmit signal from a transmit channel of the radio frequency module; a calculation subunit , configured to perform non-linear transformation on the digital transmit signal to generate a cancellation signal y(k) to be used to cancel a passive inter-modulation, PIM, component; and a superimposition subunit , configured to superimpose the cancellation signal reversely on a receive channel of the radio frequency module to cancel a PIM component of a receive signal; wherein the calculation subunit is specifically configured to generate a non-linear base of the digital transmit signal, resolve a non-linear term coefficient according to a current cancellation error, and generate the cancellation signal according to the digital transmit signal, the non-linear base, and the non-linear term coefficient, characterized in that the calculation subunit is specifically configured to calculate, according to the following formulas, said cancellation signal y(k) that is used to cancel said a PIM component: y k = ∑ CH n , p , q k ∗ x k − p ∗ NL n x k − q ; CH n , p , q k + 1 = CH n , p , q k + mu ∗ e ⊗ LPF ∗ conj x k − p ∗ NL n x k − q ⊗ LPF ; wherein x( ) denotes the digital transmit signal, y( ) denotes the cancellation signal, k denotes time, p and q denote two delays, n is used to identify different non-linear bases, CH n,p,q ( ) denotes the non-linear term coefficient, NL n ( ) is a function related to the transmit signal x( ), x(k-p)∗NL n (|x(k-q)|) denotes the non-linear base, x( ), y( ), CH n,p,q ( ), and NL n ( ) are all functions of the time k, mu denotes a step factor, LPF denotes a band-limited filter coefficient, ⊗ denotes convolution, and conj denotes conjugation. an obtaining subunit , configured to obtain a digital transmit signal from a transmit channel of the radio frequency module; a calculation subunit , configured to perform non-linear transformation on the digital transmit signal to generate a cancellation signal y(k) to be used to cancel a passive inter-modulation, PIM, component; and a superimposition subunit , configured to superimpose the cancellation signal reversely on a receive channel of the radio frequency module to cancel a PIM component of a receive signal; wherein the calculation subunit is specifically configured to generate a non-linear base of the digital transmit signal, resolve a non-linear term coefficient according to a current cancellation error, and generate the cancellation signal according to the digital transmit signal, the non-linear base, and the non-linear term coefficient, characterized in that the calculation subunit is specifically configured to calculate, according to the following formulas, said cancellation signal y(k) that is used to cancel said a PIM component: y k = ∑ CH n , p , q k ∗ x k − p ∗ NL n x k − q ; CH n , p , q k + 1 = CH n , p , q k + mu ∗ e ⊗ LPF ∗ conj x k − p ∗ NL n x k − q ⊗ LPF ; wherein x( ) denotes the digital transmit signal, y( ) denotes the cancellation signal, k denotes time, p and q denote two delays, n is used to identify different non-linear bases, CH n,p,q ( ) denotes the non-linear term coefficient, NL n ( ) is a function related to the transmit signal x( ), x(k-p)∗NL n (|x(k-q)|) denotes the non-linear base, x( ), y( ), CH n,p,q ( ), and NL n ( ) are all functions of the time k, mu denotes a step factor, LPF denotes a band-limited filter coefficient, ⊗ denotes convolution, and conj denotes conjugation. <EOS>