Karl Jay Mccormick

US Patent:

40030180, Jan 11, 1977

Filed:

Feb 9, 1976

Appl. No.:

5/656680

Inventors:

Karl McCormick - Channelview TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

G01V 116

US Classification:

340 15

Abstract:

A method and apparatus for testing a plurality of geophones disposed in either a series or series-parallel arrangement for both their activity and distortion. The activity of geophones is checked by applying a plurality of constant amplitude current pulses to the geophones and measuring the peak value of the resulting voltage. The distortion of the geophones is measured by applying a constant amplitude sinusoidal current to the geophones and detecting the harmonics of the resulting voltage.

US Patent:

40939235, Jun 6, 1978

Filed:

Dec 22, 1976

Appl. No.:

5/753658

Inventors:

Karl McCormick - Houston TX

Assignee:

Shell Oil Company - Houston TX

International Classification:

G11C 2702
H04B 1504

US Classification:

328165

Abstract:

A system for cancelling an unwanted or noise signal having a constant frequency, amplitude and phase while preserving a desired signal having the same frequency but a different phase. The system samples the noise signal N times each cycle and stores the sampled values of the signal. The sampling is terminated and the stored signals feedback at the sample rate with reversed polarity to cancel the noise signal.