Foetal ECG extraction by means of ICA is a well-known solution, but the quality of on-line algorithms is often inadequate compared to the batch ones. A block-on-line version of the JADE algorithm aimed to follow the variations in the mixing process, avoiding traces permutation in this application domain, is presented jointly with its real-time implementation on a TMS320C6713 floating-point DSP. The results on a common benchmark are comparable with those achievable with the original batch algorithm, opening the possibility to develop a realtime diagnostic device.