A method and system for enabling the determination of a position of a receiver within a space includes transmitting a beacon signal from each of a plurality of beacon devices located at different locations within the space. The beacon signal transmitted from each beacon device has a unique information component and may have a unique frequency pattern of multiple frequencies. Each beacon signal can be distinguishable from the beacon signals transmitted from any other of the beacon devices based on the combination of its unique information component and its unique frequency pattern. The beacon signals are received at a receiver. At the receiver, for each beacon signal of a working subset, time-delay information of the received beacon signal is determined and multilateration is applied to determine the position of the receiver based on the location of each beacon device of the working subset.

A method and system for enabling the determination of a position of a receiver within a space includes transmitting a beacon signal from each of a plurality of beacon devices located at different locations within the space. The beacon signal transmitted from each beacon device has a unique information component and may have a unique frequency pattern of multiple frequencies. Each beacon signal can be distinguishable from the beacon signals transmitted from any other of the beacon devices based on the combination of its unique information component and its unique frequency pattern. The beacon signals are received at a receiver. At the receiver, for each beacon signal of a working subset, time-delay information of the received beacon signal is determined and multilateration is applied to determine the position of the receiver based on the location of each beacon device of the working subset.

In one aspect, an apparatus includes: a mixer to receive a radio frequency (RF) signal and downconvert the RF signal into a second frequency signal; an amplifier coupled to the mixer to amplify the second frequency signal; an image rejection (IR) circuit coupled to the programmable gain amplifier (PGA) to orthogonally correct a gain and a phase of the amplified second frequency signal to output a corrected amplified second frequency signal; and a complex filter to filter the corrected amplified second frequency signal.

In one aspect, an apparatus includes: a mixer to receive a radio frequency (RF) signal and downconvert the RF signal into a second frequency signal; an amplifier coupled to the mixer to amplify the second frequency signal; an image rejection (IR) circuit coupled to the programmable gain amplifier (PGA) to orthogonally correct a gain and a phase of the amplified second frequency signal to output a corrected amplified second frequency signal; and a complex filter to filter the corrected amplified second frequency signal.

A system can include a housing that defines an interior space; a shaft disposed at least in part in the interior space of the housing where the shaft includes a longitudinal axis, a curved surface and an end surface; a submersible electric motor operatively coupled to the shaft where the submersible electric motor includes a cable connector; two proximity sensors where each of the proximity sensors includes a sensor aperture disposed in the interior space of the housing; and circuitry operatively coupled to the proximity sensors that determines position values of the shaft with respect to time based at least in part on output of the proximity sensors.

An automatic filtering method and device includes a step of analyzing an input signal so as to obtain its frequency spectrum; and a step of selecting, on the basis of the frequency spectrum, at least one filter from among a plurality of preset filters and filtering the input signal. The method and device automatically use a suitable filter on the basis of the frequency spectrum and repeat simulation of automatic fine adjustment to ensure a filtering effect against noise.

A method and apparatus to compensate for distortion of a waveform due to the skin effect in a current shunt. The method includes modeling the complex impedance of the shunt as component complex impedances. By designing a filter corresponding to the component complex impedances, the distortion of a waveform across the shunt may be reversed to provide an accurate replica of the undistorted waveform.

A method and apparatus to compensate for distortion of a waveform due to the skin effect in a current shunt. The method includes modeling the complex impedance of the shunt as component complex impedances. By designing a filter corresponding to the component complex impedances, the distortion of a waveform across the shunt may be reversed to provide an accurate replica of the undistorted waveform.

A measurement apparatus and method for measurement of a radio frequency, RF, signal, said measurement apparatus comprising a signal input adapted to receive an RF-signal being split into a first measurement signal path and into a second measurement signal path of said measurement apparatus, wherein said first measurement signal path is adapted to measure the split RF-signal within a predefined first frequency band around a predefined measurement frequency, wherein said second measurement signal path is adapted to measure a current frequency at a power maximum of the split RF-signal in a predefined second frequency band, and wherein the RF-signal measured in said first measurement signal path is shifted in the frequency domain depending on the current frequency measured in said second measurement signal path.

A measurement apparatus and method for measurement of a radio frequency, RF, signal, said measurement apparatus comprising a signal input adapted to receive an RF-signal being split into a first measurement signal path and into a second measurement signal path of said measurement apparatus, wherein said first measurement signal path is adapted to measure the split RF-signal within a predefined first frequency band around a predefined measurement frequency, wherein said second measurement signal path is adapted to measure a current frequency at a power maximum of the split RF-signal in a predefined second frequency band, and wherein the RF-signal measured in said first measurement signal path is shifted in the frequency domain depending on the current frequency measured in said second measurement signal path.