Abstract: Methods for assessing cable insulation are provided that can include engaging a first tine gap interdigital capacitor assembly with the exterior of the cable jacket to determine a first capacitance and dissipation factor value of the insulation using the first tine gap interdigital capacitor assembly; engaging a second tine gap interdigital capacitor assembly with the exterior of the cable jacket to determine a second capacitance and dissipation factor value of the insulation using the second tine gap interdigital capacitor assembly. Systems for assessing cable insulation are also provided. The systems can include a cable jacket encompassing cable insulation and conductive material; at least two tine gap interdigital capacitor assemblies engaged with the cable jacket; and processing circuitry operatively engaged with the capacitor assemblies.

Abstract: In an exemplary embodiment, a system for measuring smoke absorption into food products includes a surrogate that reacts to a presence of smoke in air ambient to the surrogate and the food products, the surrogate including an open container of a liquid and a probe in the form of a toroidal conductivity sensor that measures electrical conductivity of the liquid; wherein the electrical conductivity of the liquid increases as smoke is absorbed by the liquid and simultaneously into the food products; and a control that receives a signal from the toroidal conductivity sensor and in response generates a signal and/or a display indicative of the electrical conductivity of the liquid that corresponds to a selected amount of smoke absorption by the food products exposed to the smoke.

Abstract: In a general aspect of the examples described, motion is detected based on bi-directional channel sounding. In an example, a first set of channel information is obtained from a first device. The first set of channel information is based on a first set of wireless signals transmitted from a second device through a space at a first time in a timeframe. A second set of channel information is obtained from the second device. The second set of channel information is based on a second set of wireless signals transmitted from the first device through the space at a second time in the timeframe. The first and second sets of channel information are analyzed to detect a category of motion or a location of detected motion in the space during the timeframe.

Abstract: An electric circuit includes a compensation circuit. The compensation circuit includes at least one directional coupler with an adjustable coupling factor. The compensation circuit is coupled between a first signal path and a second signal path of the electric circuit via the at least one directional coupler. Furthermore, the electric circuit includes a detector circuit coupled at least to the second signal path. The detector circuit is configured to detect an interfering signal portion of a signal of the first signal path in the second signal path. Furthermore, the electric circuit includes a control circuit. The control circuit is configured to adjust a transfer characteristic of the compensation circuit based on the detected interfering signal portion. Adjusting the transfer characteristic includes adjusting the coupling factor of the at least one directional coupler.

Abstract: An inverter anti-islanding control system includes a phase-shift loop (10) and a drive circuit (20). The phase-shift loop (10) includes a first input end (11), a second input end (12), a third input end (13), a fourth input end (14), a first output end (15), and a second output end (16). The drive circuit (20) includes a first input end (21), a second input end (22), a third input end (23), and an output end (24). The first output end (15) of the phase-shift loop (10) is connected to the first input end (21) of the drive circuit (20), and the second output end (16) of the phase-shift loop (10) is connected to the second input end (22) of the drive circuit (20).

Abstract: In a general aspect, a motion detection system manages leaf nodes used for sounding by one or more access points. For example, an access point identifies one or more static leaf nodes based on presence activity of each leaf node in a calibration window. A health score is determined for each AP-leaf node link for each calibration window based on AP-leaf node link quality information. One or more of the static leaf nodes are selected to be used for sounding in the motion detection system based on the health scores for each of the AP-leaf node links. The motion detection system is then updated to use the selected one or more static leaf nodes for motion detection.

Abstract: In a general aspect, a motion detection system manages leaf nodes used for sounding by one or more access points. For example, an access point obtains presence information for a plurality of AP-leaf node links for a plurality of calibration periods. Presence activity is determined for each AP-leaf node link in each calibration period based on its respective presence information. Static leaf nodes are identified based on the presence activity for the plurality of AP-leaf node links in a calibration window, the calibration window comprising a number of the plurality of calibration periods. The motion detection system is updated to use at least one of the identified static leaf node as a sounding node for motion detection.

Abstract: There is provided a method for acquiring information regarding terrain and/or objects within a volume, said method comprising: transmitting signals over time (“node signals”) from one or more nodes of a wireless network (“subject network”); receiving the node signals after their traversing a medium (“node resultant signals”) using one or more receiving units (“node signal receivers”); measuring one or more physical attributes (“signal attributes”) for one or more of the node resultant signals, wherein at least one of the signal attributes is of at least one of the following types: (a) time difference between node signal transmission by the applicable transmitting subject network node and node resultant signal reception by the applicable node signal receiver; (b) phase difference between the transmitted node signal and the received node resultant signal; (c) power ratio between the transmitted node signal and the received node resultant signal; (d) frequency difference between the received node resultant signa

Abstract: An intelligent jack provides a physical port identifier (PPID) to an upstream device, such as a network switch. The network switch receives the PPID on a particular physical port. The network switch accesses port configuration data to configure the particular physical port, such as to a particular virtual local area network (VLAN). Port connection data associating the physical port with the PPID may be generated. Changes to the port connection data may generate an alarm.

Abstract: A communication device is provided. The communication device can include a processing device for communicating data via a data connection or receiving power via an electrical connection and a connector for providing the data connection or electrical connection. The connector can include at least one terminal and a sensing module. The terminal can be communicatively coupled to the processing device. The terminal can form the data connection or electrical connection with at least one external terminal of a mating connector. The sensing module can detect a movement associated with removing the mating connector. The sensing module can provide a termination signal to the processing device to terminate the data connection or electrical connection. The processing device can terminate data communication via the data connection or current flow via the electrical connection in response to the termination signal.

Abstract: A protection relay is provided for protection of an electric network. The protection relay measures an electric signal in the network, converts the measured signal to a frequency domain representation of the measured signal, and generates a measuring phasor based on the frequency domain representation, where the phase rotation of the measuring phasor is dependent on one or more frequency components present in the measured electric signal. The protection relay compares the measuring phasor to the reference phasor, where the phase rotation of the reference phasor is based on either a nominal or a measured frequency of the electric network, and launches protection if the comparison of the of the measuring phasor and the reference phasor fulfils a predetermined criterion.

Abstract: A method of extracting complex impedance from selected volumes of the material under test (MUT) combined with various embodiments of electrode sensor arrays. Configurations of linear and planar electrode arrays provide measured data of complex impedance of selected volumes, or voxels, of the MUT, which then can be used to extract the impedance of selected sub-volumes or sub-voxels of the MUT through application of circuit theory. The complex impedance characteristics of the sub-voxels may be used to identify variations in the properties of the various sub-voxels of the MUT, or be correlated to physical properties of the MUT using electromagnetic impedance tomography and/or spectroscopy.

Abstract: A failure detecting apparatus that detects an isolation failure between a plurality of coils included in a signal detection apparatus. The failure detecting apparatus includes a voltage applying unit that applies a DC voltage to a coil in the plurality of coils; a differential signal generating unit that generates a differential signal from a voltage at the coil and a predetermined voltage; a threshold voltage setting circuit that outputs a threshold voltage; and a comparator that compares the differential signal with the threshold voltage, thereby detecting whether or not an isolation failure exists. The differential signal generating unit includes either first setting unit for setting an absolute value of the differential signal to be amplified with a predetermined gain or second setting unit for setting the predetermined voltage to be different from a ground potential, and the predetermined gain is set to a value different from one and zero.

Abstract: A measurement system, for use in RF power measurements, allows an arbitrary Bruene-type RF coupler to be calibrated at a number of different power levels and frequencies with an idealized transfer function being created for each calibration power point. Following calibration, when the coupler is used in an operational (measurement) mode, the DC voltage corresponding to the present power measurement is read, and the discrete idealized transfer functions generated during the power and frequency calibration phases are used to determine a best fit idealized transfer function, which is used in conjunction with the exact DC voltage being measured to create a highly accurate power measurement.

Abstract: A Dicke-switched radiometer including a signal channel comprising of an antenna for receiving an input signal and a first stage amplification circuit for amplifying an output of the antenna and generating an amplified input signal; a reference channel comprising of a resistive load, a second stage amplification circuit and a matching filter for matching a frequency and an impedance of the amplified input signal to a frequency and an impedance of the amplified reference signal; a Dicke switch coupled to first stage amplification circuit and the matching filter for inputting the amplified input signal and an output of the matching filter to generate a difference signal; a third stage amplification circuit coupled to an output of the Dicke switch for amplifying the difference signal; and a detector coupled to an output of the third stage amplification circuit to obtain the amplified difference signal and generate a detected difference signal.

Abstract: A method for measuring distance includes transmitting a first pair of RF pulses from an airborne interrogator, where the first pair of RF pulses are temporally separated from each other by a first time interval and each of the RF pulses in the first pair of RF pulses has a first pulse waveform. The method also includes receiving a second pair of RF pulses transmitted by a ground transponder. The RF pulses in the second pair of RF pulses have a second pulse waveform characterized by a filtered asymmetric Gaussian function or a smoothed trapezoidal function. The method further includes determining an elapsed time between transmitting the first pair of RF pulses and receiving the second pair of RF pulses and determining a distance between the airborne interrogator and the ground transponder based on at least the elapsed time.

Abstract: A method for measuring distance includes transmitting a first pair of RF pulses from an airborne interrogator, where the first pair of RF pulses are temporally separated from each other by a first time interval and each of the RF pulses in the first pair of RF pulses has a first pulse waveform. The method also includes receiving a second pair of RF pulses transmitted by a ground transponder. The RF pulses in the second pair of RF pulses have a second pulse waveform characterized by a smoothed concave polygonal function and/or a smoothed concave hexagonal function. The method further includes determining an elapsed time between transmitting the first pair of RF pulses and receiving the second pair of RF pulses and determining a distance between the airborne interrogator and the ground transponder based on at least the elapsed time.

Abstract: Methods of detecting a plug insertion into a plug aperture of a communications connector are provided in which a control signal is transmitted to a control signal input circuit of the connector that includes a reactive coupling element. The control signal is electromagnetically coupled through the control signal input circuit. The electromagnetically coupled control signal is thereafter detected on a first differential pair of conductive paths that are included in the connector. A determination is made that a plug is present in the plug aperture based at least in part on detecting the electromagnetically coupled control signal on the first differential pair of conductive paths.

Abstract: An inductive proximity switch for detecting the presence of an object in a monitored area includes a coil (2), a pulse source (4) for supplying the coil (2) with transmitting current pulses (S1, S2, S3) at a period (T) larger than the duration (Ts) of the transmitting current pulses, and a processing circuit (6) for generating an output signal (9) based on received voltages (Ui1, Ui2, Ui3) varying in dependence of a change of position of the object. The received voltages are induced in the coil (2) after the duration (Ts) of a transmitting current pulse by the decaying current which previously flows in the object due to the voltage induced therein by the coil. The proximity switch has a suppression circuit (13, 13a, 13b, 13c) for suppressing a signal duration lower than a predetermined perturbation time (Tc1, Tc2) in the output signal (9).

Abstract: Methods of detecting a plug insertion into a plug aperture of a communications connector are provided in which a control signal is received that is electromagnetically coupled across a plug aperture of the communications connector using a reactive coupling element. A determination may be made that a mating plug (e.g., an RJ-45 plug or a connector on a fiber optic jumper cable) has been inserted into the plug aperture based on this received control signal. Related connectors are also provided.

Abstract: A proximity switch assembly and method for detecting activation of a proximity switch assembly is provided. The assembly includes a plurality of proximity switches each having a proximity sensor providing a sense activation field and control circuitry processing the activation field of each proximity switch to sense activation. The control circuitry monitors the signal responsive to the activation field and determines a differential change in generated signal, and further generates an activation output when the differential signal exceeds a threshold. The control circuitry further distinguishes an activation from an exploration of the plurality of switches and may determine activation upon detection of a stable signal.

Abstract: A vehicle proximity switch and method are provided having sensitivity control based on a user selected sensitivity input. The switch includes a proximity sensor such, as a capacitive sensor, installed in a vehicle and providing a sense activation field. The proximity switch also includes control circuitry for processing the sense activation field to sense user activation of the switch by comparing the sense activation field to a threshold. The proximity switch further includes a user sensitivity input for receiving a user selected sensitivity input. The control circuitry controls sensitivity of the comparison based on the user selected sensitivity input.

Abstract: A Dicke-switched radiometer including a signal channel comprising of an antenna for receiving an input signal and a first stage amplification circuit for amplifying an output of the antenna and generating an amplified input signal; a reference channel comprising of a resistive load, a second stage amplification circuit and a matching filter for matching a frequency and an impedance of the amplified input signal to a frequency and an impedance of the amplified reference signal; a Dicke switch coupled to first stage amplification circuit and the matching filter for inputting the amplified input signal and an output of the matching filter to generate a difference signal; a third stage amplification circuit coupled to an output of the Dicke switch for amplifying the difference signal; and a detector coupled to an output of the third stage amplification circuit to obtain the amplified difference signal and generate a detected difference signal.

Abstract: A locating appliance configured to sense an article includes a push-pull measurement bridge and a comparator. The push-pull measurement bridge is configured to actuate a first electromagnetic device and a second electromagnetic device, in each case in a variable ratio. The first electromagnetic device takes the actuation as a basis for producing an electromagnetic alternating field in a region of the article. The comparator is configured to sense the article if the variable ratio differs from a predetermined ratio by more than a predetermined amount.

Abstract: In one aspect, a method to detect an object in an area includes forming a wireless network among a plurality of nodes, each of the nodes being configured to generate an electromagnetic field (EMF) in the area and determining changes in the EMF between two nodes based on: a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value, a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and a third difference in link quality values between a previously determined link quality value and a currently determined link quality value. The method further comprises detecting the object based on the changes in the EMF.

Abstract: A system and method for controlling an impedance tuner system. In one embodiment, a web-enabled electronic controller controls an impedance tuner system including a signal transmission line and an electronically-controllable impedance-varying system coupled to the signal transmission line for affecting the impedance presented by the signal transmission line. The controller has a communication port, and an electronic processor configured to process external command signals and generate electronic control signals to configure the impedance-varying system in response to the command signals. An electronic memory stores sets of data and one or more web pages. The controller has a communication server and is configured to receive or send signals through a communication channel from or to a client computer system. The communication server is configured to be responsive to a request message from a client computer system to send a response comprising a web page to the client computer system.

Abstract: A device determines a first voltage measurement of an output of a first brick. The device further determines a second voltage measurement associated with a second brick. The first brick is larger in size than the second brick. The device ramps up an output voltage of the second brick when the second voltage measurement is less than the first voltage measurement.

Abstract: A method includes receiving data corresponding to a voltage level over time and a current level over time. The method also includes determining a first ratio corresponding to a voltage ramp percent or a voltage falling edge percent with respect to a peak in the voltage level and determining a second ratio corresponding to a current ramp ratio or a current falling edge ratio with respect to a peak in the current level. The method further includes determining, based on a comparison between the first ratio and the second ratio, whether to increment, decrement, or maintain an inductance compensation estimation value corresponding to an estimated inductance present in one or more secondary components associated with the welding operation.

Abstract: A method and apparatus of determining the condition of a bulk tissue sample, by: positioning a bulk tissue sample between a pair of induction coils (or antennae); passing a spectrum of alternating current (or voltage) through a first of the induction coils (or antennae); measuring spectrum of alternating current (or voltage) produced in the second of the induction coils (or antennae); and comparing the phase shift between the spectrum of alternating currents (or voltages) in the first and second induction coils (or antennae), thereby determining the condition of the bulk tissue sample.

Abstract: Systems provide for a test system for capacitors in a digitally controllable oscillator (DCO). The system includes: capacitor toggling logic configured to switch on and off a selected one of the capacitors at a modulation frequency; a tone generator configured to generate a tone; a mixer configured to receive the tone and an output carrier signal from the DCO while the capacitor toggling logic is switching the selected one of the capacitors on and off and to output an intermediate frequency signal having FM sidebands based on the modulation frequency and relative capacitor size; and an evaluation circuit configured to evaluate a frequency deviation associated with the selected one of the capacitors based on at least one of the FM sidebands.

Abstract: A method for controlling an amplitude of an incoming light is provided. The method includes attenuating a portion of the incoming light within a first band having a tunable peak attenuation wavelength using a tunable filter; passing a portion of the incoming light from the tunable filter within a second band using a fixed filter; and controlling the amplitude of the incoming light by tuning the peak attenuation wavelength of the tunable filter.

Abstract: An FET RF signal detector circuit comprising two unbalanced differential transistor pair circuits is disclosed. A current mirror output circuit is included for generating an output current derived from currents flowing in the differential transistor pair circuits. The first unbalanced differential transistor pair circuit comprises two branches, each with a respective tail, and a first variable resistor between the branch tails. The first unbalanced differential transistor pair circuit connects to a first current source tail arrangement. The second unbalanced differential transistor pair circuit comprises two branches, each with a respective tail, and a second variable resistor between the branch tails. The second unbalanced differential transistor pair circuit connects to a second current source tail arrangement.

Abstract: In a sensor control circuit, an impedance signal output unit has a HPF, a P/H circuit, a LPF, etc., and detects an element impedance of a sensor element on the basis of an impedance response signal which is alternately changed in response to an alternating current signal supplied to the sensor element. The P/H circuit has an input comparator which inputs an impedance detection voltage Vz after the HPF, a rectifying element connected to the P/H circuit, and a hold capacitor which is charged by the output of the input comparator. The input comparator has a constant current circuit and a transistor. The constant current circuit limits an updating value of a hold voltage value Vph of the hold capacitor every alternating current period. The sensor control device detects the element impedance of the sensor element with high accuracy while preventing influence of noise.

Abstract: A device with at least one channel for measuring high dynamic range, radio frequency (RF) power levels over broad-ranging duty cycles includes a power sensor circuit comprising at least one logarithmic amplifier; at least one directional RF coupler electrically connected to the at least one power sensor; at least one RF attenuator electrically connected to the at least one RF coupler; and at least one sampling circuit electrically connected to the at least one RF attenuator and the at least one RF coupler. The at least one sampling circuit performs analog-to-digital conversion of electrical signals received to provide digitals signals for measuring the RF power level in the at least one channel.

Abstract: For proximity detection, capacitance of a sensing element to ground is measured as one or more objects move into or out of proximity to the sensing element.

Abstract: A capacitive proximity sensor circuit capable of distinguishing between instances of detected user proximity includes one or more guard electrodes, a first sensor, and a second sensor. The capacitive proximity sensor is installed in a device such that a first sensor faces a first component of the device, and the second sensor faces a second component of the device. The first and second sensors measure a capacitance to detect proximity of a user relative to the respective sensor. The guard electrode is provided to mitigate stray capacitance to reduce error in the capacitance measurements obtained by the first and second sensors.

Abstract: A measuring device with at least one control unit and an electrical current controller. The measuring- and operating electronics is connected to a current loop and the control unit is connected with the electrical current controller and provides the electrical current controller a reference input. The reference input corresponds to a desired value of the measurement signal current and the electrical current controller is suppliable with a primary feedback signal. The primary feedback signal corresponds to an actual value of the measurement signal current set in the current loop. The electrical current controller outputs a control signal formed from a control error signal, wherein at least one evaluation unit is provided, which compares at least one value of the control signal output by the electrical current controller with at least one reference value. The comparison indicates whether the value of the control signal exceeds or subceeds the reference value.

Abstract: Various embodiments include solutions for in-process material characterization. Various particular embodiments include a computer-implemented method including: providing instructions for transmitting oscillating electromagnetic field signals to a material under test (MUT); obtaining a return signal associated with the transmitted oscillating electromagnetic field signals; comparing the return signal with the oscillating electromagnetic field signals to determine a difference in an aspect of the return signal and the aspect of the oscillating electromagnetic field signals; comparing the difference in the aspect to a predetermined threshold; and determining a characteristic of the MUT based upon the compared difference.

Abstract: A capacitive sensor unit is disposed for contactlessly actuating a vehicle door. The sensor unit has an electrode assembly with at least three electrodes that are disposed in a spaced relationship. The electrodes include a first transmitting electrode, a second transmitting electrode, and a receiving electrode arranged between the two transmitting electrodes.

Abstract: A proximity switch assembly and method for detecting activation of a proximity switch assembly is provided. The assembly includes a plurality of proximity switches each having a proximity sensor providing a sense activation field and control circuitry processing the activation field of each proximity switch to sense activation. The control circuitry monitors the signal responsive to the activation field and determines a differential change in generated signal, and further generates an activation output when the differential signal exceeds a threshold. The control circuitry further distinguishes an activation from an exploration of the plurality of switches and may determine activation upon detection of a stable signal.

Abstract: A system for testing a DC power supply performance includes a comparison module, a judge module, and an alarm module. The comparison module receives DC voltage signals from the DC power supply, compares the DC voltage signals with a reference voltage respectively, and outputs a voltage level signal when the DC power supply is normal. The judge module receives the voltage level signal, and outputs a control signal according to the voltage level signal. The alarm module receives the control signal, and indicates status of the DC power supply according to the control signal.

Abstract: A method of detecting the position of the armature (3) of an electromagnetic actuator arranged and able to move between first and second coils (1, 2), in which a voltage jump (UB) is applied to the first and the second coils (1, 2) of the actuator connected in series. The first and the second coils (1, 2) form a voltage divider in accordance with the impedance coil principle. The voltage (U1) of the first coil (1) and the voltage (U2) of the second coil (2) are measured and, from the measurement data for the voltages at the first and the second coils (1, 2), the quotient of the difference (?U) between the two voltage values and the voltage jump (UB), normalized in relation to the size of the voltage jump (UB) is calculated, and a specific armature stroke is correlated one-to-one with each value of the quotient.

Abstract: A locating appliance configured to sense an article includes a push-pull measurement bridge and a comparator. The push-pull measurement bridge is configured to actuate a first electromagnetic device and a second electromagnetic device, in each case in a variable ratio. The first electromagnetic device takes the actuation as a basis for producing an electromagnetic alternating field in a region of the article. The comparator is configured to sense the article if the variable ratio differs from a predetermined ratio by more than a predetermined amount.

Abstract: A method, implemented by a software-controlled computer device and/or by dedicated hardware, for probing an electrically conductive target material, e.g. molten metal or semiconductor material, in a metallurgical vessel. In the method, a measurement signal is acquired from a sensor, which is inserted into the target material, during a relative displacement between the electrically conductive target material and the sensor, the measurement signal being indicative of electrical conductivity in the vicinity of the sensor. The measurement signal is generated to represent momentary changes in an electromagnetic field around the sensor, which is created by operating at least one coil in the sensor. Based on the measurement signal, a signal profile is generated to be indicative of the electrical conductivity as a function of the relative movement. The method enables a probing of the internal distribution of the target material in the vessel at any level of detail.

Abstract: A vehicle proximity switch and method are provided having sensitivity control based on a user selected sensitivity input. The switch includes a proximity sensor such, as a capacitive sensor, installed in a vehicle and providing a sense activation field. The proximity switch also includes control circuitry for processing the sense activation field to sense user activation of the switch by comparing the sense activation field to a threshold. The proximity switch further includes a user sensitivity input for receiving a user selected sensitivity input. The control circuitry controls sensitivity of the comparison based on the user selected sensitivity input.

Abstract: An electronic circuit detecting proximity includes an excitation coil emitting an inductive excitation field toward a target. A first pair of detection coils obtains a first differential inductive signal that is modified by a transition of the target within the inductive field. An out-of phase second pair of detection coils obtains a second differential inductive signal that is modified by a transition of the target within the inductive field. A comparator generates a transition signal when the difference between the first and second differential signals reaches a threshold value. A stationary target, in a ferromagnetic or conductive material, creates an offset to the signals at the outlet of the coil pairs. The offset is decreased during the presence of a movable target within the same type of material or increased during the presence of a movable target within another type of material. A comparator detects the offset level.

Abstract: A unit cell of a narrow band filter is provided. The unit cell includes a matrix body having a first permittivity and an inclusion body having a second permittivity and disposed in the matrix body. The matrix body and the inclusion body are configured to reflect electromagnetic radiation incident on electromagnetic radiation facing surfaces of the matrix body and the inclusion body. A bandwidth of the reflected electromagnetic radiation is based on a difference between the first permittivity and a third permittivity, which is an average permittivity between the first permittivity and the second permittivity based on volumes of the inclusion body and a portion of the matrix body. The inclusion body is configured such that the second permittivity is adjustable to adjust the third permittivity, thereby adjusting the difference between the first permittivity and the third permittivity. A narrow band filter and a method are also disclosed.

Abstract: Systems provide for a test system for capacitors in a digitally controllable oscillator (DCO). The system includes: capacitor toggling logic configured to switch on and off a selected one of the capacitors at a modulation frequency; a tone generator configured to generate a tone; a mixer configured to receive the tone and an output carrier signal from the DCO while the capacitor toggling logic is switching the selected one of the capacitors on and off and to output an intermediate frequency signal having FM sidebands based on the modulation frequency and relative capacitor size; and an evaluation circuit configured to evaluate a frequency deviation associated with the selected one of the capacitors based on at least one of the FM sidebands.

Abstract: An inductive proximity switch for detecting the presence of an object in a monitored area includes a coil (2), a pulse source (4) for supplying the coil (2) with transmitting current pulses (S1, S2, S3) at a period (T) larger than the duration (Ts) of the transmitting current pulses, and a processing circuit (6) for generating an output signal (9) based on received voltages (Ui1, Ui2, Ui3) varying in dependence of a change of position of the object. The received voltages are induced in the coil (2) after the duration (Ts) of a transmitting current pulse by the decaying current which previously flows in the object due to the voltage induced therein by the coil. The proximity switch has a suppression circuit (13, 13a, 13b, 13c) for suppressing a signal duration lower than a predetermined perturbation time (Tc1, Tc2) in the output signal (9).

Abstract: In one aspect, a method to detect an object in an area includes forming a wireless network among a plurality of nodes, each of the nodes being configured to generate an electromagnetic field (EMF) in the area and determining changes in the EMF between two nodes based on: a first difference in received signal strength values between a previously determined received signal strength value and a currently determined received signal strength value, a second difference in received signal strength values between the currently determined received signal strength value and an average received signal strength value and a third difference in link quality values between a previously determined link quality value and a currently determined link quality value. The method further comprises detecting the object based on the changes in the EMF.