A method can include in a first phase of a sensing operation, controlling at least a first switch to energize a sensor inductance; in a second phase of the sensing operation that follows the first phase, controlling at least a second switch to couple the sensor inductance to a first modulator capacitance to induce a first fly-back current from the sensor inductance, the first fly-back current generating a first modulator voltage at the first modulator capacitance, and in response to the first modulator voltage, controlling at least a third switch to generate a balance current that flows in an opposite direction to the fly-back current at the first modulator node. The first and second phases can be repeated to generate a first modulator voltage at the first modulator capacitance. the modulator voltage can be converted into a digital value representing the sensor inductance. Related devices and systems are also disclosed.

A system includes a power converter including a primary bridge unit to receive a primary voltage from a voltage source, the primary bridge unit includes a first plurality of electronic switches, and each of the first plurality of electronics switches has a turn ON time and a turn OFF time. Further, the power converter includes a transformer including a primary winding and a secondary winding, the primary winding is coupled to the first plurality of electronic switches. Also, the power converter includes a secondary bridge unit including a second plurality of electronic switches coupled to the secondary winding. Additionally, the system includes a controller to determine an inductance of the power converter based on the primary voltage, the turn ON time of the first plurality of electronic switches, a switching cycle time of the power converter, and one of an average current and a peak current in the power converter.

An inductive alignment system is provided. The system includes a power source providing a forcing function and a first inductor in communication with the power source. The first inductor exhibits a first electrical property in response to the forcing function. The system also includes a second inductor in communication with the first inductor. The second inductor exhibits a second electrical property in response to the forcing function. The system includes a comparator that compares the first electrical property with the second electrical property and generates a signal based at least in part on a deviation between the first electrical property and the second electrical property. The deviation is caused at least in part by inductive coupling between a proximate object and at least one of the first inductor and the second inductor. A method of inductive alignment using the above system is also provided.

Circuitry for estimating an inductance of an inductor in power converter circuitry, the circuitry comprising: circuitry for generating a peak inductor current signal indicative of a peak inductor current during an operational cycle of the power converter circuitry; circuitry for generating a ripple current estimate signal, indicative of an estimate of a ripple current in the power converter circuitry; and circuitry for applying the ripple current estimate signal to the peak inductor current signal to generate an average inductor current threshold signal indicative of an estimated average inductor current in the power converter circuitry during the operational cycle, wherein the ripple current estimate signal is based on: a duration of a charging phase of operation of the power converter circuitry; a voltage across the inductor; and an inductance value for the inductor; and wherein the circuitry for generating the ripple current estimate signal is operative to select an inductance value for the inductor for which the estimated average inductor current is equal to an actual average inductor current during the operational cycle to generate a value for the actual inductance of the inductor.

One inductive sensor is configured to maintain a fixed frequency in a resonant circuit. One apparatus includes an inductance-to-digital converter (LDC). The LDC includes a digital filter to measure an inductance change of a sensor and convert the inductance change to a digital value. The LDC further includes a digital control loop to maintain a fixed frequency in the sensor. The sensor forms an oscillator in the digital control loop. An output of the digital control loop is representative of the inductance change of the sensor.

Various embodiments include apparatus and methods to operate an induction measurement process in a borehole that addresses direct coupling of a signal between sensors of a measuring tool. Apparatus and methods can include a processing unit to generate formation parameters from signals received in the measurement tool. Additional apparatus, systems, and methods are disclosed.

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor with a plurality of driving signals, each driving signal of the plurality of driving signals having a respective driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure a first value of a physical quantity associated with the resistive-inductive-capacitive sensor in response to a first driving signal of the plurality of driving signals, wherein the first driving signal has a first driving frequency; measure a second value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to a second driving signal of the plurality of driving signals, wherein the second driving signal has a second driving frequency; measure a third value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the first driving signal; measure a fourth value of the physical quantity associated with the resistive-inductive-capacitive sensor in response to the second driving signal; determine a first difference between the third value and the first value; determine a second difference between the fourth value and the second value; and based on the first difference and the second difference, determine if a change in a resonant property of the resistive-inductive-capacitive sensor has occurred, and determine if a change in a quality factor of the resistive-inductive-capacitive sensor has occurred.

It is described an attenuation measurement device (100), comprising:

i) a detector unit (110) having a coupling capacitance (120), and an input capacitance (130), wherein the detector unit (110) is configured to produce a detector output signal (112a,b) in reply to an input signal received at the coupling capacitance (120) and/or at the input capacitance (130);
ii) a test unit (140), coupled to the detector unit (110), and configured to provide a test signal (141) with at least one known signal property as a first input signal to the coupling capacitance (120);
iii) a calibration unit (150), coupled to the detector unit (110), and configured to provide a calibration signal (151) as a second input signal to the input capacitance (130); and
iv) a control unit configured to
a) determine a first detector output signal (112a) produced by the detector unit (110) in response to the test signal (141),
b) identify a specific calibration signal (151) that yields a second detector output signal (112b) that is comparable to the first detector output signal (112a), and
c) derive a capacitance-indicative information based on the identified specific calibration signal (151).

A method of assessing whether a vehicle is straddled between lanes (12,14) on a multi-lane carriageway, the method comprising the steps of: a) measuring inductance change values from two adjacent inductive loops (22a, 20b) situated at a loop site, as the vehicle traverses the loop site; b) summing separate logarithms of the inductance change values, or taking a logarithm of the product of the inductance change values, to obtain a value; and c) comparing the value from step (b) against a predetermined threshold value to make a determination as to whether: i) a single vehicle is straddling multiple lanes (12,14), where the value from step (b) is on one side of the predetermined threshold value, or ii) two vehicles are present in adjacent lanes (12,14), where the value from step (b) is on the other side of the predetermined threshold value.

The device for the impedance-based probing of materials described herein comprises a two-dimensional array of coils (1) and a measurement unit (4) adapted to determine, for each coil (1), a parameter indicative of its impedance. A pulse generator (3) is able to generate current pulses in each coil (1). The circuitry drives and senses the coil array through row and column lines (rp1 . . . rpN1, cp1 . . . cpN2, c21 . . . csN2) in order to minimize the number of required components. The device can, in particular, be used for probing concrete.