Patent ID: 7183771

Claim:
A method of obtaining an electromagnetic propagation measurement of a subterranean geologic formation, said geologic formation being intersected by a borehole, the method comprising: providing a device within the borehole, said device comprising: a transmitter, located on said device, for transmitting a signal; a first receiver and a second receiver located on said device, for receiving the transmitted signal; and, a processor means for processing the received signals; generating the signal from the transmitter; receiving the transmitted signal at the first and second receiver; injecting a calibration signal with a calibration circuit into the first receiver and the second receiver; processing the receiver signal and the calibration signal within the processor means and wherein the step of processing the receiver signal and the calibration signal includes calculating a phase difference free of data acquiring errors by computing the phase difference as follows: PD =(θ M1 −θ M2 )−(θ MC1 −θ MC2 ) Wherein PD is the phase difference free from acquisition errors; θ M1 is the measured phase of the uncalibrated receiver signal from the first receiver; θ M2 is the measured phase of the uncalibrated receiver signal from the second receiver; θ MC1 is the measured phase of the calibration signal from the first receiver; and, θ MC2 is the measured phase of the calibration signal from the second receiver: correcting data acquisition errors related to the receiver and the second receiver; determining the electromagnetic propagation measurement.