Modem with optimum gain echo canceller adaptation.

摘要

The modem of the system includes a data sending access (45) for sending symbols to a remote apparatus, a receiving access (46) for receiving symbols originating from this remote apparatus, echo cancelling means consisting of filtering means (50, 54) with adjustable coefficients and of a phase-shifting means (56) in cascade for supplying information originating from the said sending access, filtered and phase-shifted to a subtraction means (58, 52) in order to remove the said filtered phase-shifted information from the receiving access data, a control means for acting on the filtering means and the phase-shifting means in order to cancel any possible echo at the output of the subtraction means. This method proposes the following stages: - estimation of the energy of the echo for a time corresponding to a certain number of symbols, - assignment of this energy to a number in simple form - carrying on with the setting of the coefficients and of the phase-shifting element by means of the said allocation. Application: data transmission. <IMAGE>