A magnetic field sensor for detecting motion of an object includes one or more magnetic field sensing elements configured to generate a magnetic field signal in response to a magnetic field associated with the object and a detector configured to generate a comparison signal having edges occurring in response to a comparison of the magnetic field signal and a threshold signal and occurring at a rate corresponding to a speed of motion of the object. A speed monitor responsive to the comparison signal is configured to generate a speed signal having a value indicative of the speed of motion of the object. A threshold generator having an input coupled to receive the speed signal from the speed monitor and an output coupled to the detector is configured to generate the threshold signal at a first level when the value of the speed signal indicates that the speed of motion of the object is greater than a predetermined speed and at a second level when the value of the speed signal indicates that the speed of motion of the object is less than the predetermined speed.

A magnetic field sensor for detecting motion of an object includes one or more magnetic field sensing elements configured to generate a magnetic field signal in response to a magnetic field associated with the object and a detector configured to generate a comparison signal having edges occurring in response to a comparison of the magnetic field signal and a threshold signal and occurring at a rate corresponding to a speed of motion of the object. A speed monitor responsive to the comparison signal is configured to generate a speed signal having a value indicative of the speed of motion of the object. A threshold generator having an input coupled to receive the speed signal from the speed monitor and an output coupled to the detector is configured to generate the threshold signal at a first level when the value of the speed signal indicates that the speed of motion of the object is greater than a predetermined speed and at a second level when the value of the speed signal indicates that the speed of motion of the object is less than the predetermined speed.

A magnetic field sensor for detecting motion of an object includes one or more magnetic field sensing elements configured to generate a magnetic field signal in response to a magnetic field associated with the object and a detector configured to generate a comparison signal having edges occurring in response to a comparison of the magnetic field signal and a threshold signal and occurring at a rate corresponding to a speed of motion of the object. A speed monitor responsive to the comparison signal is configured to generate a speed signal having a value indicative of the speed of motion of the object. A threshold generator having an input coupled to receive the speed signal from the speed monitor and an output coupled to the detector is configured to generate the threshold signal at a first level when the value of the speed signal indicates that the speed of motion of the object is greater than a predetermined speed and at a second level when the value of the speed signal indicates that the speed of motion of the object is less than the predetermined speed.

A magnetic field measurement cable (10) of the present disclosure includes an electric cable (1) provided at an axial part, and an outer circumferential cable (2) provided on the outer side of the electric cable (1) and helically formed by a plurality of steel wires helically wound and a magnetic field measurement optical cable (3) having an optical fiber cable (3a).

A magnetic field measurement cable (10) of the present disclosure includes an electric cable (1) provided at an axial part, and an outer circumferential cable (2) provided on the outer side of the electric cable (1) and helically formed by a plurality of steel wires helically wound and a magnetic field measurement optical cable (3) having an optical fiber cable (3a).

An exemplary magnetic field measurement system includes a wearable sensor unit and a single controller. The wearable sensor unit includes a plurality of magnetometers. The single controller is configured to generate a single clock signal and use the single clock signal to drive one or more components within the magnetometers.

An exemplary controller may include a single clock source configured to generate a single clock signal used to drive one or more components within a plurality of magnetometers and a plurality of differential signal measurement circuits configured to measure current output by a photodetector of each of the plurality of magnetometers.

The present invention describes an electromagnetically positioning system, which can measure a position and orientation of a remote object in an isolated targeted examination area with time. Specifically, the remote object is a remote miniaturized examination device. During the location process, both the electromagnetically positioning system and the remote miniaturized examination device can have expected or unexpected, controlled and can-not-be-controlled movement. By implementing the electromagnetically positioning system, disclosed herein, position and orientation information of the remote miniaturized examination device can be linked with time, any information collected by the remote miniaturized examination device, for example, the photo images collected, can be associated kinetically with time and positioning information of the examination device, when the remote miniaturized examination device travels inside an isolated target examination area.

An object of the present invention is to selectively detect a detection magnetic field without separately providing a sensor for detecting an environmental magnetic field. A magnetic field detection device includes a magnetic field detection unit 10 that generates an output signal S1 according to a magnetic field, a first signal generation unit 20 that extracts a predetermined frequency component from the output signal S1 and generates a cancel signal S2 based on the predetermined frequency component, a first magnetic field generation unit 40 that applies a first cancel magnetic field to the magnetic field detection unit 10 based on the cancel signal S2, and a second signal generation unit 30 that generates a detection signal S3 based on the output signal S1 of the magnetic field detection unit 10 to which the first cancel magnetic field is applied. According to the present invention, a cancel signal is generated based on a frequency component of an output signal, and a first cancel magnetic field is applied to a magnetic field detection unit using the cancel signal. Therefore, it is not necessary to separately provide a sensor for detecting an environmental magnetic field. Because this configuration reduces the number of parts, downsizing and cost reduction can be realized.

An object of the present invention is to selectively detect a detection magnetic field without separately providing a sensor for detecting an environmental magnetic field. A magnetic field detection device includes a magnetic field detection unit 10 that generates an output signal S1 according to a magnetic field, a first signal generation unit 20 that extracts a predetermined frequency component from the output signal S1 and generates a cancel signal S2 based on the predetermined frequency component, a first magnetic field generation unit 40 that applies a first cancel magnetic field to the magnetic field detection unit 10 based on the cancel signal S2, and a second signal generation unit 30 that generates a detection signal S3 based on the output signal S1 of the magnetic field detection unit 10 to which the first cancel magnetic field is applied. According to the present invention, a cancel signal is generated based on a frequency component of an output signal, and a first cancel magnetic field is applied to a magnetic field detection unit using the cancel signal. Therefore, it is not necessary to separately provide a sensor for detecting an environmental magnetic field. Because this configuration reduces the number of parts, downsizing and cost reduction can be realized.