| 摘要 |
PURPOSE:To eliminate the need for a large-capacity capacitor for integration which is necessary before by applying digital technology to a bridged tap equivalent circuit. CONSTITUTION:An input signal E0 containing an echo is led to an output terminal E1 through an analog adder 31 and a part of the signal is converted through OP amplifiers 32, 33, and 34 into digital signals E2-E4, which are led to a control part 35. Then, outputs E5 and E6 of this control part are applied to an up/ down counter 36 which accumulates the amounts of echo after one time slot and an up/down counter 37 which accumulates the amount of echo after two time slots. The outputs of both counters 36 and 37 are processed by addition or subtraction through a digital adder and subtracter 38 and then converted by a D/A converter 39 into an analog signal, which is smoothed by a smoothing circuit 40 and then supplied as an echo canceler signal to an adder 31. |
