RECEIVING APPARATUS

摘要

A receiving apparatus for receiving information transmitted from a bottomhole to a surface by means of electromagnetic waves. The receiving apparatus includes a receiving antenna for receiving a transmitted signal from the bottomhole, a noise detector for detecting noise current received by the receiving antenna, and a noise canceller for removing noise components received by the receiving antenna by comparing an output signal from the receiving antenna and an output signal of the noise detector. The noise canceller is a noise canceller using parallel adaptive filters, and includes a plurality of adaptive filters arranged in parallel fashion, an adder for summing output signals of the plurality of adaptive filters, and a subtracter for subtracting an output signal of the adder from a main input signal.