ECHO CANCELLER DEVICE

PURPOSE:To simplify the constitution of a D/A converter and to reduce the quantized noises for an echo canceller device such as a telephone set, etc., by extracting and controlling an effective pseudo echo line signal in response to the echo properties of a hybrid circuit. CONSTITUTION:A pseudo echo signal of m-bit word length is produced on the basis of the estimated echo line properties of a hybrid circuit 1, and at the same time a squaring/totalizing process is given to an impulse answer signal showing the estimated echo properties. Based on this squared and totalized value, the n-bit component is extracted out of the m-bit pseudo echo signal. This n-bit component undergoes a D/A conversion through a D/A converter 8, and the level of this converted output signal is controlled by a level controlling circuit 17 in accordance with the squared and totalized value. Then an echo eliminating pseudo echo signal is produced and then subtracted from the output signal of the receiving terminal of the circuit 1.