Echo cancellation in two-wire transmission path repeaters

摘要: A two-wire transmission path repeater includes, between two hybrid circuits coupled to the path, an echo canceller and amplifier for each direction of transmission, including a transversal filter subtracting circuit. The power ratio signals before after circuit is used distinguish simplex duplex signals. If exceeds given value, which dependent upon input signal power, only one then in opposite determined, gain reduced, adaptation coefficients prevented. both directions falls below value amplifiers increased transfer filters continued short period, reduced prevented, thereby facilitating stable operation repeater.