A transmitter system for transmitting a plurality of input transmission signals on respective antenna ports, the transmitter system comprising: ▪ a plurality of signal paths, each signal path comprising: ∘ an input node (32-1,..., 32-M) for receiving an input transmission signal of the plurality of input transmission signals; ∘ an antenna port (33-1,..., 33-M); ∘ an analogue portion of the signal path connected to the antenna port (33 -1,..., 33-M), said antenna port (33-1,..., 33-M) being associated with a multi-antenna array; ∘ a Dual-Input Digital Predistortion, DI DPD, module (30-1,..., 30-M) coupled to the input node (32-1,..., 32-M) and the analogue portion of the signal path, the DI DPD module being configured to provide a predistorted input transmission signal to the analogue portion of the signal path in response to a received Crosstalk and Mismatch, CTM, signal and the input transmission signal; and ▪ one or more Crosstalk and Mismatch, CTM, modules configured to receive one or more of the plurality of transmission signals, and characterized by the one or more CTM modules being further configured to separately generate for each DI DPD module (30-1,..., 30-M) the CTM signal, said CTM signals representing CTM distortions caused by one or more output transmission signals of each said analogue portion of the corresponding signal path. ▪ a plurality of signal paths, each signal path comprising: ∘ an input node (32-1,..., 32-M) for receiving an input transmission signal of the plurality of input transmission signals; ∘ an antenna port (33-1,..., 33-M); ∘ an analogue portion of the signal path connected to the antenna port (33 -1,..., 33-M), said antenna port (33-1,..., 33-M) being associated with a multi-antenna array; ∘ a Dual-Input Digital Predistortion, DI DPD, module (30-1,..., 30-M) coupled to the input node (32-1,..., 32-M) and the analogue portion of the signal path, the DI DPD module being configured to provide a predistorted input transmission signal to the analogue portion of the signal path in response to a received Crosstalk and Mismatch, CTM, signal and the input transmission signal; and ∘ an input node (32-1,..., 32-M) for receiving an input transmission signal of the plurality of input transmission signals; ∘ an antenna port (33-1,..., 33-M); ∘ an analogue portion of the signal path connected to the antenna port (33 -1,..., 33-M), said antenna port (33-1,..., 33-M) being associated with a multi-antenna array; ∘ a Dual-Input Digital Predistortion, DI DPD, module (30-1,..., 30-M) coupled to the input node (32-1,..., 32-M) and the analogue portion of the signal path, the DI DPD module being configured to provide a predistorted input transmission signal to the analogue portion of the signal path in response to a received Crosstalk and Mismatch, CTM, signal and the input transmission signal; and ▪ one or more Crosstalk and Mismatch, CTM, modules configured to receive one or more of the plurality of transmission signals, and characterized by the one or more CTM modules being further configured to separately generate for each DI DPD module (30-1,..., 30-M) the CTM signal, said CTM signals representing CTM distortions caused by one or more output transmission signals of each said analogue portion of the corresponding signal path.