Title: Digital echo canceler for a modem for data transmission by means of modulation of a carrier

Abstract: Digital echo canceler for a modem for data transmission by means of phase and, possibly, also amplitude modulation of a carrier, the ratio between carrier frequency f.sub.o and modulation rate 1/T having the form P/Q, P and Q being integers. The echo canceler receives the binary data to be transmitted for generating an echo copy signal. An echo canceler of a simple implementation is obtained in that the echo canceler comprises means responsive to each symbol configuration at each instant iT for generating at least a number depending on the amplitude allotted to the carrier at said instant iT and for applying this number to at least a given section of an assembly of adaptive digital filter whose output signals are combined for forming a digital version of the echo copy signal, the coefficients of these filters being adjusted by an assembly of adjusting circuits receiving said error signal in digital form and arranged for minimizing a predetermined function of said error signal.

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Inventors: Baudoux, Jean-Pierre (Paris, FR)
Macchi, Cesar D. (Orsay, FR)

Application Number: 869508
Filing Date: 1978-01-16
Publication_date: 1979-07-24
Assignee: Telecommunications Radioelectriques et Telephoniques TRT (Paris, FR)
Primary Class(es): 379/406.08 370/290
Other Classes:
US Patent Ref:

3732410	May, 1973	Mackechnie	179/170.
3903377	Sep, 1975	Sato	179/170.
4072830	Feb, 1978	Gitlin et al.	179/170.
4074086	Feb, 1978	Falconer et al.	179/170.
4087654	May, 1978	Mueller	179/170.
4117277	Sep, 1978	VAN DEN Elzen et al.	179/170.

Other Refs:
Primary Examiner: Claffy, Kathleen H.
Assistant Examiner: Myers, Randall P.
Attorney: Briody; Thomas A., Streeter; William J.