An electrical circuit includes: at least one inductor, at least one varactor, and at least two transistors, all of which electrically arranged to form a voltage controlled oscillator (VCO) having an oscillation frequency; wherein the at least two transistors includes a first transistor and a second transistor; wherein the first transistor has a first bulk terminal and a first parasitic diode disposed between the first bulk terminal and the first transistor; wherein the second transistor has a second bulk terminal and a second parasitic diode disposed between the second bulk terminal and the second transistor; wherein application of a first control voltage to the first bulk terminal, application of a second control voltage to the second bulk terminal, or application of first and second control voltages to the first and second bulk terminals, respectively, is effective to change the oscillation frequency of the VCO.

A system includes a voltage-controlled oscillator (VCO) to generate an output signal based on an input voltage and a multi-stage delay network to receive the output signal from the VCO. Each stage of the delay network produces a phase-shifted output signal. The system includes a multi-stage digital-to-analog converter (DAC) network, where each stage of the DAC network is associated with a corresponding stage of the delay network. Each stage of the DAC network receives the phase-shifted output signal from its corresponding stage of the delay network and generates a weighted output signal based on the received phase-shifted output signal. The DAC network combines the weighted output signal of each stage. A weighting factor for each stage of the DAC network is selected to reduce harmonic content of the combination of weighted output signals.

Capacitors connected between gate terminals of a plurality of parallel-connected power transistors are charged and discharged in each switching cycle to provide a plurality of power transistor control waveforms from a single gate driver waveform that equalize power losses/temperatures or steady-state currents among the plurality of power transistors. The capacitors are charged to different voltages by diverting current from one transistor driver by disabling another power transistor driver at different respective times in response to measured transient or steady state current or temperature or other operational parameter.

An integrated circuit includes a drive circuit with a first inverter circuit with a first transistor of a first conductivity type and a second transistor of a second conductivity type. The drains of the first and second transistors are connected. An output circuit is provided having a third transistor of the second conductivity with a gate connected to the drains of the first and second transistors. A capacitor is connected between the gate and a drain of the third transistor and has a capacitance greater than 0.5 pF and less than or equal to 3.0 pF. A gate width of the first transistor when divided by a gate width of the third transistor has a value of less than 1/100. The output circuit is configured to output a transmission signal from the drain of the third transistor.

In some embodiments, a phase-locked loop (PLL) system comprises a phase-frequency detector (PFD) configured to compare a phase-frequency reference signal and a feedback signal, a charge pump (CP) electrically coupled to the PFD and configured to produce a first tuning signal based on an output of the PFD, multiple integrator cells electrically coupled to the CP and configured to output multiple second tuning signals based on a voltage of the first tuning signal relative to a voltage reference signal, and a voltage-controlled oscillator (VCO) electrically coupled to the CP and to the multiple integrator cells and configured to adjust a capacitance value of the VCO based on the multiple second tuning signals. The capacitance value and the first tuning signal affect a frequency of the feedback signal.

A loop filter with an active discrete-level loop filter capacitor can be used in a VCO (such as for CDR). A loop filter capacitor function is simulated by sensing input loop filter current (such as with a current mirror and source follower in the input leg), and forcing back a loop filter (VCO) control voltage. Loop filter voltage control is provided using a VDAC with a discrete-level VDAC feedback voltage, incremented/decremented based on the sensed loop filter current. In one embodiment, the VDAC voltage is provided as the non-inverting input to an amplifier, with the inverting input providing the control voltage, forced to the VDAC feedback voltage. The VDAC feedback voltage can be provided by increment/decrement comparators based on a voltage deviation on a C2 capacitor (from a reference voltage) that receives the sensed loop filter current (effectively multiplying the C2 capacitance to provide a simulated loop filter capacitance).

A phase locked loop (PLL) includes a controllable oscillator, a charge pump, a type II loop filter, a frequency divider, a phase error processing circuit, a phase frequency detector and a phase alignment circuit. The controllable oscillator generates an oscillating signal. The charge pump circuit generates a charge pump output in a calibration mode. The type II loop filter generates a first control signal to the controllable oscillator according to the charge pump output. The frequency divider performs frequency division upon the oscillating signal for generating a feedback signal. The phase error processing circuit outputs an adjusting signal by comparing a reference signal with the feedback signal. The phase frequency detector generates a detection signal by comparing the feedback signal and the reference signal. The phase alignment circuit generates a second control signal in the calibration mode.

An apparatus includes an integrated circuit (IC). The IC includes a power controller, which includes a regulator and a controller. The regulator receives a plurality of input voltages and provides a regulated output voltage. The controller controls the regulator to generate the regulated output voltage from the plurality of input voltages. The power controller provides power to a load integrated in the IC from a set of arbitrary input voltages. The set of arbitrary input voltages includes the plurality of input voltages.

To provide a clock selection circuit capable of reducing clock omission generated when switching from a state of being synchronized with a first clock to a second clock. The clock selection circuit is equipped with a clock detection circuit which detects a first clock to output a detected signal, a switch which outputs the first clock when the detected signal is at a first level and outputs a second clock when the detected signal is at a second level different from the first level, and a one-shot circuit which outputs a one-shot pulse in response to switching of the detected signal from the first level to the second level. The output of the switch and the output of the one-shot circuit are added to be outputted as an output clock.

A radio-frequency (RF) switch includes a field-effect transistor (FET) disposed between a first node and a second node, the FET having a source, a drain, a gate, and a body. The RF switch further includes a coupling circuit including a first path and a second path, the first path being connected between the gate and one of the source or the drain via a first resistor in series with a first capacitor, the second path being connected between the body and the one of the source or the drain via a second resistor in series with a second capacitor, the coupling circuit configured to allow discharge of interface charge from either or both of the gate and body.

This application relates to methods and apparatus for phase locked loops. A phase-and-frequency detector (101) receives a reference clock signal (CKref) and a feedback signal (SFB) and outputs a first adjustment signal (U) that is modulated between respective first and second signal levels to provide control pulses indicating that an increase in frequency required for phase and frequency lock, and a second adjustment signal (D) that is modulated between respective first and second signal levels to provide control pulses indicating that a decrease in frequency required for phase and frequency lock. First and second time-to-digital converters (201-1 and 201-2) receive the first and second adjustment signals respectively and output respective first and second digital signals indicative of the duration of said control pulses. Each time-to-digital converter comprises a controlled-oscillator (401, 801) configured so as to operate at a first frequency when the respective adjustment signal is at the first signal level and operate at a second frequency when the respective adjustment signal is at the second signal level and a counter (403) configured to produce a count value of the number oscillations of the controlled-oscillator in each of a succession of count periods defined by a count clock signal. The first and second digital signals are based on the count values output from the respective counters. The difference between the first and second digital signals may be determined and input to digital loop filter (203) before driving numerically-controlled-oscillator (204) to produce the output signal.

Disclosed is an anode for a molten carbonate fuel cell (MCFC) having improved creep property by adding an additive for imparting creep resistance to nickel-aluminum alloy and nickel as materials for an anode. Improved sintering property, creep property and increased mechanical strength of a molten carbonate fuel cell may be obtained accordingly.

A flowing electrolyte fuel cell system design (DHCFC-Flow) is provided. The use of a flowing oxygen-saturated electrolyte in a fuel cell offers a significant enhancement in the cell performance characteristics. The mass transfer and reaction kinetics of the superoxide/peroxide/oxide ion (mobile oxygen ion species) in the fuel cell are enhanced by recirculating an oxidizing gas-saturated electrolyte. Recirculating oxygen-saturated electrolyte through a liquid channel enhances the maximal current observed in a fuel cell. The use of a oxygen saturated electrolyte ensures that the reaction kinetics of the oxygen reduction reaction are fast and the use of convection ameliorates concentration gradients and the diffusion-limited maximum current density. The superoxide ion is generated in situ by the reduction of the oxygen dissolved in the gaseous electrolyte. Also, a dual porosity membrane allows the uniform flow of fuel (e.g., methane) on the fuel side, without allowing phase mixing. The capillary pressure for liquid intrusion into the gas phase and vice versa is quite large, estimated to be 1-10 psi. This makes it easier to control the fluctuations in gas/liquid velocity which might otherwise lead to phase mixing and the loss of fuel cell performance. In one variation, a dual-porosity membrane structure is incorporated in the system to allow uniform flow of fuel and prevent mixing of fuel with a liquid electrolyte.

A flow battery includes a positive electrode, a positive electrode electrolyte, a negative electrode, a negative electrode electrolyte, and a polymer electrolyte membrane interposed between the positive electrode and the negative electrode. The positive electrode electrolyte includes water and a first redox couple. The first redox couple includes a first organic compound which includes a first moiety in conjugation with a second moiety. The first organic compound is reduced during discharge while during charging the reduction product of the first organic compound is oxidized to the first organic compound. The negative electrode electrolyte includes water and a second redox couple. The second couple includes a second organic compound including a first moiety in conjugation with a second moiety. The reduction product of the second organic compound is oxidized to the second organic compound during discharge.

The described technology relates to an electrolyte solution comprising a sulfur dioxide-based ionic liquid electrolyte, and a sodium-sulfur dioxide (Na—SO2) secondary battery having same, one purpose of the described technology being to enhance the storage characteristics of sulfur dioxide gas in an electrolyte solution. The sodium-sulfur dioxide secondary battery includes a negative electrode which is formed from an inorganic material and which contains sodium. The battery also includes a positive electrode which is formed from a carbon material and a sulfur dioxide-based inorganic electrolyte solution. Here, the electrolyte solution contains a sulfur dioxide-based ionic liquid electrolyte prepared by injecting SO2 gas in an ionic liquid.

The invention relates to a housing (10) for accommodating a plurality of battery cells (20), in particular lithium-ion battery cells, wherein the housing (10), in particular a plastic housing, comprises a cooling device with an inlet point (30) and an outlet point (40) for an air stream (22) for cooling the battery cells (20). In addition, the housing (10) is designed as a single piece together with the cooling device integrated in the housing (10), and the cooling device additionally has spacers (34; 34a, 34b) for arranging all accommodated battery cells (20) with an intermediate space (23) for guiding air between the battery cells (20), by which means an air channel (25) is provided for the air stream (22) between the battery cells (20). The invention further relates to a battery pack (50) and to a motor vehicle comprising such a battery pack (50).

A crosslapper receives a card web and folds it into a lap intended to be needle-punched or consolidated by other ways. The web includes zones which are more condensed, having a spectrum of orientation of fibers with a component parallel to the width of the web, alternating with less condensed zones having a longitudinal unidirectional spectrum of orientations. The zones which are less condensed are used to form the edge zones of the lap. The result is that the lap has different respective spectra of orientation which pre-compensate for the unwanted changes produced by the needle-punching or other consolidation which follows. A needle-punched lap is obtained having a uniform MD/CD ratio (relationship between longitudinal and respectively transverse tensile strengths) or having a sought profile of the MD/CD ratio across the width of the lap.

The present invention provides cellulose-based fibers including cellulose and at least one polymer selected from the group consisting of a polysiloxane, a polyacrylic acid, a polyacrylamide, an m-aramid, and a polyvinylalcohol/polystyrene copolymer, and a tire cord including the same. Furthermore, the cellulose-based fibers of the present invention have an advantage in superior elongation and tenacity of the prior cellulose fibers by blending at least one polymer having a functional group that is capable of a hydrogen bond with a hydroxyl group of a cellulose molecule.

In a device on a spinning room preparation machine, for example a fiber flock feeder, carding machine, cleaner or the like, for supplying and/or discharging fiber material, a tray-like guide element having a guide surface co-operates with at least one conveyor roll located opposite, the fiber material being guided towards and along the guide surface. In order to provide a simple way of supplying and/or discharging fiber material without undesirable adhesion of fibers, the guide element located opposite the at least one conveyor roll is arranged to be set in vibration by at least one actuator.

The present invention relates to a method for the continuous production of laid staple fiber fabrics with aligned fiber orientation, in which method the laid fabrics are produced by continuous plaiting down of carded fiber web at defined laying angles onto a synchronized transport belt (1), wherein the carding machine (2) and plaiting means (3) arranged downstream of it are arranged at an acute angle with respect to the advancing direction of the transport belt. Said laid staple fiber fabrics are used for producing high-strength fiber-reinforced plastic composites, as are used in wind power plants, aircraft construction and the automotive industry. In particular in the loading direction, said composites have high composite strengths and rigidities, to which end a defined fiber orientation is required. In addition to a defined orientation of the finite fibers, the laid fabrics also have a defined mass per unit area.

The purpose of the invention is to reduce the abrasive impact of the fiber or the yarn on the rollers coated with elastic material, which are used for drafting and guiding purposes in yarn production techniques, and thus keep the operating conditions and yarn quality parameters constant. The fiber on the top rollers coated with elastic material especially in the mechanical ring compact yarn production among the yarn production techniques, is an apron cladding method, over the top roller and the bearing guide arms connected to a bearing body found on the bearing unit placed on the pressure arm, in a way that it would cover these together. The method includes the operation steps of stretching the aprons by application of tension via a tension component and, while the fiber drafting operation continues, the bearing unit carrying the aprons being shifted in the horizontal plane in certain intervals.

Systems and methods for removing material, e.g., linters, from seeds, e.g., ginned cottonseeds, are provided. The systems and methods involve rotating the seeds in a rotatable drum having a plurality of longitudinal brushes. The centrifugal force created by the rotation of the drum and the plurality of longitudinal brushes urge the seeds against an interior surface of the drum that is lined with a brush insert. In this way, work is performed that removes the material from the exterior of the seeds. The material is removed using reduced pressure and the processed seeds are removed. The system may include a brush insert that is easily removed from the rotatable drum. Other systems and methods are disclosed.

A module feeder system is disclosed. The module feeder system comprises a module feeder which has an unload bed, a feeder bed, a first side wall and a second side wall. A cutting device is attached to the feeder bed. At least one hydraulic cylinder is positioned on each of the first and second side walls. Each hydraulic cylinder is configured to project in a direction away from the sidewalls and over the feeder bed. A method used to unwrap a cotton module is also disclosed.

A reclaimer cylinder for use in reclaiming cotton seeds containing spinnable lint from partially ginned cotton seeds utilizes channel saws mounted axially on a cylindrical body with axially closely spaced teeth that virtually eliminate the variation in likelihood the teeth will fail to grasp the fibers present on such cotton seeds. Triangular grid bars facilitate removal of fully ginned seeds that are not entrained in fibers of other seeds.

The device for producing a uniform or profiled fleece or a fiber flock mat includes a material dispensing device which produces a fleece and a transport device for the further transport of the fleece. The device also includes a measuring device to determine a transverse profile and a longitudinal profile of the fleece by measuring the mass per unit area of the fleece across its width, and a profile-changing device for supplying individualized fibers or fiber flocks to the fleece. A control unit controls the profile-changing device on the basis of the results of the measuring device in such a way that the profile-changing device supplies the individualized fibers or fiber flocks section by section in a targeted manner. Thus, depending on the purpose of the application, a uniform fleece or a fleece with a nonuniform transverse profile or longitudinal profile can be produced.

A connection device for setting up an arrangement of a plurality of loudspeaker boxes that are suspended beneath one another comprises a first assembly rail which is provided for assembly on a first loudspeaker box and to which a latching part is attached, and a second assembly rail which is provided for assembly on a second loudspeaker box and to which a retaining element that interacts with the latching part is attached. Herein, a free path length of a longitudinal displaceability of the latching part in relation to the first assembly rail is preselectable. Furthermore, the position of the retaining element in relation to the second assembly rail is preselectable.

An intermediate support structure for an escalator or moving walk having a dampening device with slots formed therein allowing a supported escalator truss to be free to move laterally to accommodate lateral displacement caused by story drift during an earthquake or seismic event.

A gimbal system, including apparatus and methods, with one or more gimbals having non-preloaded or preloaded vibration isolators, a biased preloading compensation mechanism, sag compensation, and/or lateral snubbing.

An apparatus for reverse mounting an electronic device in a server housing is provided. The apparatus includes a first bracket, a second bracket, and a coupling. The first bracket couples to the device body and extends outward from the device body toward a front rail of the server housing. The first bracket includes a first end configured to releasably couple to front rail of the server housing. The second bracket includes a protrusion that extends outward from the device body in an opposite direction relative to the first bracket. The coupling includes a first portion that couples to a rear rail of the server housing and a second portion defining a channel that receives the protrusion of the second bracket.

Embodiments are disclosed that relate to mounting brackets for speakers. In some embodiments, a mounting bracket includes a first plate portion; a second plate portion, the second plate portion perpendicular to the first plate portion; and a slot extending continuously from the first plate portion to the second plate portion.

This invention is a mounting system for a loudspeaker system that is capable of positioning and re-positioning the box-like device of the loudspeaker without requiring the use of any retaining/tensioning fasteners. A bracket facilitates constraining the positioning and repositioning for the roll and pitch axes while simultaneously providing audible feedback angular movement indication that enable vertical and horizontal orientation with respect both to the installation environment and to match its positioning to other like installed systems.

A transformable bed for examinations in pediatric ophthalmology, especially suitable for the use of general anesthesia when conducting eye examinations, is provided. The bed may include a fixed bed board, a movable bed board, a movable seat, a movable support, a securing strap, and a main frame. The bed may be fixedly connected to the top of the main frame, the movable bed board may be rotationally connected to the top of the main frame, and the movable seat may be rotationally connected to the top of the main frame. The securing strap may be disposed on the movable bed board, in which one end of the movable support may be removably connected to the movable bed board, and another end may be removably connected to the main frame. The transformable bed may function both as an anesthesia bed and a handcart, and may be quickly switched therebetween.

A backboard for an automated cardio pulmonary resuscitation system, said backboard comprising a board element, the board element defining a plane and having a top edge, a bottom edge a first side edge and a second side edge; a set of connectors adapted for connection of the backboard to an automated cardio pulmonary resuscitation unit, said connectors being provided at said side edges; and at least one set of stabilizing elements extending away from an edge and transversely to said plane.

Levitation devices are disclosed for use with beds. In one embodiment, the levitation device is configured to facilitate rotation of a mattress with respect to a box spring. In another embodiment, the levitation device is configured to facilitate making a bed which allows sheets and blankets to be tucked between the mattress and the box spring without the need to lift the mattress. In a third embodiment, the levitation device functions as a hybrid device and can be used for making a bed or rotating a mattress.

The present invention provides a patient positioning device, which enables the latest advances in Stereotactic Radiation Therapy. The geometry, which incorporates at least one window or lateral cut-out, is designed to allow clear treatment access to the patient during non-coplanar treatment regimes through the use of windows or lateral cut-outs. A laterally positionable diaphragm compression device allows the full use of the geometry. The development of a stand-alone device and a couch top insert device allows for a maximum number of protocol methods while minimizing the skin surface radiation dose to the patient.

A movable lift device including a rotatable bed which can be lifted or rotated by a user, with laying a user thereon. The movable lift device having a rotatable bed includes a base frame comprising a plurality of wheels installed therein; a post rotatably coupled to the base frame, the post upwardly extended from the base frame a predetermined length in an “L” shape; and a bed comprising a bed part that is able to ascend along the post, the bed part allowing a user to lie thereon. The post rotatably supporting the bed has an “L” shape and the supporting point of the post rotatably supporting the bed is formed in the center of the base frame, such that the structure may be stably maintained even when the bed having the patient lying thereon is rotated, only to prevent an accident of overturning the movable lift device.

A stretcher including an upper frame for mounting a lifter thereon, a front leg pivotably attached to the upper frame, a rear leg pivotably attached to the upper frame, a fixed caster attached to one end of the front leg, a swivel caster attached to one end of the rear leg, and an auxiliary swivel caster attached to the front leg, wherein the upper frame is vertically adjustable by folding the front and rear legs relative to the upper frame, and wherein the auxiliary swivel caster is positioned relative to the fixed caster such that the auxiliary swivel caster is in contact with the ground when the upper frame is fully lowered and the front leg is folded away from the rear leg, and the auxiliary swivel caster is out of contact with the ground when the upper frame is fully lowered and the front leg is folded toward the rear leg.

A foldable bed may include a first bed unit and a second bed unit. The first bed unit has a first bed frame and a second bed frame. Underneath the first and second bed frames are restorable leg and rear leg, so the first bed unit can be safely disposed on the ground. One side of the first and second bed frame has a first joint mechanism. The second bed unit has a first bed frame and a second bed frame, which are supported by a supporting leg, so the second bed unit can be safely disposed on the ground. A long slot on the first bed frame and second bed frame is provided for a securing unit to insert to connect with a connecting hole of the first joint mechanism, so the first bed unit and second bed unit can be connected as a foldable sofa bed.

An electric bed has a bed frame, multiple boards, and a motor structure. The bed frame comprises a lower bed frame and an upper bed frame, and the upper bed frame and the lower bed frame are connected by a connecting structure. The multiple boards are hinged, and at least one board is fixed onto the upper bed frame. The motor structure comprises a connecting rod, a slide bar, and a horizontal pushing motor system. The connecting rod has one end hinged with the first board of the multiple boards. The slide bar extends in the width direction of the bed frame and is arranged in a sliding chute in the length direction of the bed frame, so that it can slide along the length direction of the bed frame.

A bed vibration system to provide controllable vibrations beneath a mattress, which is located on a bed, the system comprising: a frame attachable to the bed by at least four suspension modules; at least two vibration modules, each vibration module having a rotatable element; at least two travel tracks attachable to the frame, the travel tracks configurable to have the at least two vibration modules respectively displaceable thereupon; and a vibration module control unit configurable to control vibrations and displacement of the respective vibration modules.

Disclosed is a bed clothing system that has a bottom sheet and top sheet attached together at the corners of the foot end of the bed clothing system. At the foot end of the bed clothing system on the corners, where the top and bottom sheets are attached, a stretchable piece of material is disposed in a vertical direction so that the bed sheet system is able to accommodate to any size and thickness of a mattress, while also remaining securely fixed on a mattress.

A movable privacy screen includes a plurality of privacy screen segments that are attachable to a bed or gurney. The plurality of screen segments include at least first and second screen segments. Each of the first and second screen segments include a first support pole, a second support pole and a coupler. The first support pole has a variable length to permit the first support pole to move between a collapsed configuration and an expanded configuration. The second support pole has a variable length to permit the second support pole to move between a collapsed configuration and an expanded configuration. The coupler movably couples the first and second support poles to the bed in a spaced relation to permit the first and second support poles to move between an upstanding use position and a lowered storage position. A fabric-like screen member is coupled to each of the first and second support poles. The fabric-like screen member is sized to extend between the first and second support poles, and is movable between a raised use position and a lowered storage position.

A bed with an integral toilet includes a frame, a mattress and a support for supporting the mattress on the bed frame. The mattress and support define an opening extending through the mattress and support. A robotic system removes and replaces a cushion for filling the opening and for replacing the toilet in alignment with the opening. An integral bidet, a source of clean water, a nozzle, a variable speed pump and mechanism for connecting a source of water to the bidet are included. A second opening in a lower portion of the toilet is connected to a waste storage tank. An odor eliminator is provided and a remote control allows a patient to control the unit.

A medical examination table includes a seat, a compartment below the seat, a first extension, a second extension, a lift mechanism, a base, and a storage section formed in the base. The first extension is configured to be stored in the compartment, and is further configured to project outward relative to the seat when in an extended configuration of the first extension. The second extension is configured to be stored in the compartment with the first extension, and is further configured to project outward relative to the first extension when in an extended configuration of the second extension. The lift mechanism is configured to raise and lower the seat, the compartment, and the first and second extensions. The base is coupled to the lift mechanism.

A patient support includes a frame, a patient support surface supported at the frame, a display incorporated into the frame, and a user interface incorporated into the frame. The patient support frame includes a controller incorporated into the frame, which has a plurality of prompts stored therein. The user interface is in communication with the controller and may be used to select a selected prompt from the plurality of prompts stored in the controller. When a prompt is selected, the controller generates a display image or text associated with the selected prompt at the display in response to a passage of time or an input to provide a visual prompt to the user.

Person support apparatuses with selectively coupled foot sections are disclosed. In one embodiment, the person support apparatus includes a base frame, a primary support frame supported on the base frame, and a foot section coupled to the primary support frame. The person support apparatus also includes a carriage that is freely translatable between a head end of the primary support frame and a foot end of the primary support frame, the carriage comprising a torso portion and a seat portion having a thigh segment and a gluteal segment. The person support apparatus further includes a selectable trunnion that selectively and severally couples the foot section to the primary support frame and the thigh segment of the seat portion.

A modular wall includes a plurality of inter-connectable and interchangeable wall modules. At least one of the wall modules includes a recessed, extendable piece of furniture, such as a bed, desk, table, work surface or chair. When in a closed configuration, the furniture folds into or otherwise resides within a recessed pocket in the modular wall. When in the closed configuration, the outer surface of the furniture forms an exterior surface of the wall module; thereby, concealing the furniture seamlessly into the modular wall. The exterior surface can comprise one or more exterior interchangeable tiles.

A method for reducing noise at a wellsite includes transmitting a plurality of first signals from a variable frequency drive (VFD) to an alternating current (AC) induction motor. A timing of a plurality of second signals is varied to control transistors in an inverter of the VFD, thereby reducing harmonic distortion of the first signals output from the VFD. The timing is varied based at least partially upon an estimation of the harmonic distortion.

In accordance with embodiments of the present disclosure, systems and methods for sensing and communicating sensed downhole parameters using a hybrid micro-structured fiber optic cable are provided. The micro-structured fiber optic cable may be used to communicate and/or amplify sensor signals indicative of the sensed downhole parameters. These sensed downhole parameters may include one or more of a downhole temperature, pressure, magnetic field, electromagnetic energy, radioactivity, telemetry signal, or some other downhole measurement. The micro-structured fiber optic cable may include opto-electronic circuitry built into the internal structure of the cable for modulating the optical signal based on the sensed parameters. The opto-electronic circuitry may include diodes, triodes, and other components that are communicatively coupled to external sensors used to measure downhole parameters. The opto-electronic circuitry may include an internal sensor in the form of a functional material disposed within the micro-structured fiber optic cable for measuring downhole parameters.

A system includes an optical fiber and an interrogator to provide source light to the optical fiber. The system also includes a receiver coupled to the optical fiber. The receiver includes at least one fiber optic coupler that receives backscattered light and that produces optical interferometry signals from the backscattered light. The receiver also includes photo-detectors that produce an electrical signal for each of said optical interferometry signals. The system also includes at least one digitizer that digitizes the electrical signals. The system also includes at least one processing unit that calculates I/Q data from the digitized electrical signals, corrects the I/Q data based on ellipse fitting, determines phase values based on the corrected I/Q data, and determines distributed sensing parameter values based on the phase values.