A muzzle-mounted chronograph for measuring velocities of projectiles launched from firearms. The chronograph includes a sensor module and a controller. The sensor module includes a first and second coils and a device for applying a stable magnetic field to the first and second coils. The controller determines a velocity of a projectile passing by the first and second coils based on detected variations in magnetic fields at the first and second coils.

A muzzle-mounted chronograph for measuring velocities of projectiles launched from firearms. The chronograph includes a sensor module and a controller. The sensor module includes a first and second coils and a device for applying a stable magnetic field to the first and second coils. The controller determines a velocity of a projectile passing by the first and second coils based on detected variations in magnetic fields at the first and second coils.

An inductive charging system can include a transmitter device and a receiver device. The transmitter device may be adapted to detect when a receiver coil in the receiver device is coupled to a transmitter coil in the transmitter device. For example, the current input into a DC-to-AC converter in the transmitter device can be measured and coil coupling detected when the current equals or exceeds a threshold value.

An inductive charging system can include a transmitter device and a receiver device. The transmitter device may be adapted to detect when a receiver coil in the receiver device is coupled to a transmitter coil in the transmitter device. For example, the current input into a DC-to-AC converter in the transmitter device can be measured and coil coupling detected when the current equals or exceeds a threshold value.

A magnetic field probe, a magnetic field measurement system, and a magnetic field measurement method are provided. The magnetic field probe includes a probe head. The probe head includes a first and second inner metal layer. The first inner metal layer includes a first sensing part and a first connecting part coupled thereto. The first sensing part is configured for detecting a magnetic field signal of a device under test to form a first magnetic field distribution signal. The second inner metal layer includes a second sensing part and a second connecting part coupled thereto. The second sensing part is configured for detecting the magnetic field signal of the device under test to form a second magnetic field distribution signal. A distance between the first sensing part and the device under test is smaller than that between the second sensing part and the device under test.

A method of detecting a fault in a power distribution system includes placing a signal on the system at a frequency F.sub.1 and then detecting a change in the signal due to a change in the impedance of the system as a result of a fault wherein the change is one of a change in phase, a change in signal tone, or a change in voltage level at the load. In one embodiment, band reject filters can be used to diminish the signal at the load or source. In another embodiment, the power source can be a periodic pulsed power source and the signal can be placed on the system during an idle phase of the periodic pulsed power.

A method of detecting a fault in a power distribution system includes placing a signal on the system at a frequency F.sub.1 and then detecting a change in the signal due to a change in the impedance of the system as a result of a fault wherein the change is one of a change in phase, a change in signal tone, or a change in voltage level at the load. In one embodiment, band reject filters can be used to diminish the signal at the load or source. In another embodiment, the power source can be a periodic pulsed power source and the signal can be placed on the system during an idle phase of the periodic pulsed power.

A test fixture for testing performance of a trimmed cable and/or antenna components. The test fixture may be connected without the use of solder allowing for accurate testing or tuning of one or more the antenna components.

A test fixture for testing performance of a trimmed cable and/or antenna components. The test fixture may be connected without the use of solder allowing for accurate testing or tuning of one or more the antenna components.

Methods, systems and apparatus are provided to apply a magnetic pre-conditioning to magnetic tunneling junction (MTJ) sensors and other micro-magnetic devices after fabrication but before testing, trimming or other subsequent processing. The fabricated sensor device is passed through a magnetic field that has a known direction and orientation relative to the device so that the device is placed into a known state prior to final testing and trimming. Various embodiments allow the field to be applied in situ by a permanent magnet or electromagnet as the devices are being processed by a conventional device handler or similar processing system.