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Echo Suppressor Disclosure Number: IPCOM000060875D
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09

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Couturier, C Galand, C [+details]


In a digital voice network connected to a telephone network, the voice signal is transmitted over a bidirectional 2-wire line to a hybrid transformer which separates incoming from outgoing signals. In conventional echo suppressors, the echo is detected by comparing incoming EL and outgoing ER signal energies within the digital voice processor and opening a switch S whenever ER>EL. In the present application, the process is performed over segments of voice signals 20 ms long. This process presents main drawbacks whenever the local station is talking. A method is proposed here to avoid these drawbacks. The energy ER of the Xout(n) and the energy ER of the Xin(n) signals are computed over each 20 ms block of samples through 10 consecutive values (each 2 ms long, and including 16 samples).