Method and apparatus for cancelling powerline noise in geophysical electromagnetic exploration
This paper discusses an apparatus for cancelling a narrow band noise of known frequency in geophysical electromagnetic receiving equipment having a sensing antenna for receiving electromagnetic signals including the narrow band noise. It comprises a cancelling antenna located in proximity to the sensing antenna such that the cancelling antenna can create an electromagnetic field that is of equal amplitude to the narrow band noise as detected by the sensing antenna; alternating current means connected to the cancelling antennas for generating an alternating current in the cancelling antenna, the generated alternating current being of the same frequency as the narrow band noise, the generated alternating current in the cancelling antenna creating an electromagnetic field that is 180 degrees out of phase and of equal amplitude to the narrow band noise as detected by the sensing antenna.
- Assignee:
- Atlantic Richfield Co., Los Angeles, CA (USA)
- Patent Number(s):
- US 4996484; A
- Application Number:
- PPN: US 7-291687
- OSTI ID:
- 5296531
- Resource Relation:
- Patent File Date: 29 Dec 1988
- Country of Publication:
- United States
- Language:
- English
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