| 摘要 |
1,203,801. Echo suppressors. WESTERN ELECTRIC CO. Inc. 26 Oct., 1967 [31 Oct., 1966], No. 48660/67. Heading H4R. In a long-distance system such as one involving a communication satellite having one-way channels 16, 26 separated at the terminals by the usual hybrid arrangements, the signal currents arriving over the incoming channel are applied to a generalized filter 30 which supplies a number of linear transformations through gain-adjusting networks 33 to a summing amplifier 34 to be subtracted from the outgoing signals in a network 25 to cancel echo currents arising in the hybrid. The filter 30 preferably comprises simple tapped RC ladder networks adjusted to give Laguerre function responses, the transfer ratios of the elements being as indicated. On account of the erratic level variations of the outgoing signals, an error control 28, preferably employing an infinite clipper, is connected to the outgoing channel to feed modulators 31 which also receive the outputs of the filter 30 and control, through integrators 32, the gain-adjusting networks 33. This control, however, may be disabled at an interposed gate 29 by a speech detector 36 which responds to any sudden burst of double-talking. |
