摘要 |
An apparatus for cancelling an undesired signal includes a programmable filter in which differential waveforms of a desired signal are superimposed on one another to form a composite signal similar to an undesired signal, a control circuit for detecting a level of the undesired signal to control the gain of a level adjusting circuit of the programmable filter so as to have a value proportional to the undesired signal, and a subtracter for subtracting the composite signal from an input signal.
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