32results about How to "Increase tuning speed" patented technology

A nanoparticle-enhanced liquid crystal phase shifter is provided including a first substrate layer, a plurality of electrodes attached to the substrate layer, a ground plane layer attached to a second substrate layer, and a liquid crystal layer between the ground plane layer and the first substrate layer, including a suspension of a liquid crystal material and highly polarizable nanoparticles having specific shape and size characteristics.

Planar lenses and reflectors are described comprising subwavelength high-contrast gratings (HCG) having high index of refraction grating elements spaced apart from one another in straight and/or curved segments and surrounded by low index material. The high-contrast grating is configured to receive an incident wave which excites multiple modes within the high-contrast grating and is focused for reflection and/or transmission by said high contrast grating. The width of the high contrast grating bars vary along a distribution direction of the grating bars which is perpendicular to the length of the grating bars and/or varies along the length of one or more grating bars to focus said reflection and/or transmission. The HCG is configured to provide double focusing, whose use is exemplified within a vertical cavity surface emitting laser (VCSEL) structure using focusing HCG structures for both the top and bottom mirrors.

A method for creating variants of a DTV service, a method which is simpler than the method defined in GBS0600, and the method can handle all use-case scenarios for simulcast linking in a way almost equal to that defined in GBS0600. The method introduces switching between a mother service and a variant service, the mother service being a default service to which a receiver should tune, and the variant service being a service selected at a receiver side and linked to the mother service by a service link defining a switching relation between the mother service and the variant service. The method is defined by including switching information into the data-stream of the mother service, receiving the mother service data-stream, reading the switching information, and switching from the mother service to the variant service accordingly. The switching information can be carried in EPG data and thus utilize existing data structures. EPG data of the mother service, e.g. in the form of EIT data, can be used to carry switching data, expect for variant service events different from the mother service, where the EPG/EIT data are preferably cross-carried by the mother and variant service. Preferably, the receiver selects which one of a plurality of possible variant service to switch to, e.g. based on receiver capabilities and/or user access rights. Thus, EIT carriage efficiency for services with a large degree of sharing is high, and it offers advantages in tuning speed. Further, the method will lead to simpler and consistent receiver implementations.

The invention discloses a doping structure for improving efficiency and bandwidth of a silicon-based electro-optic tuning device. The doping structure comprises a P+ type doping area arranged on the outer ridge area on one side close to the edge and is in ohmic contact with the above metal; A P type doping area is arranged on the outer ridge area connected with the P+ type doping area and extends to the inner ridge area; An N+ type doping area is arranged on the outer ridge area on the other side close to the edge and is in ohimic contact with the above metal; A N-type doping area is arranged on the outer ridge area connected with the N+ type doping area and extends to the inner ridge area and is complementary with the P type doping area; An almost-I type doping area is arranged between the P type doping area and the N type doping area and forms an almost PIN knot with the P type doping area and the N type doping area. By means of the doping structure, the silicon-based electro-optic tuning device is improved in the aspects of the modulator speed, efficiency and insertion loss, the cost is reduced, the requirement of the ion implantation process for the mask alignment accuracy is reduced, and large-scale manufacture of the device is facilitated.

A dual usage HCG VCSEL detector is provided with a high contrast grating (HCG) reflector first reflector that has a two dimensional periodic structure. The two dimensional structure is a periodic structure that is a symmetric structure with periodic repeating. The symmetrical structure provides that polarization modes of light are undistinguishable. A second reflector is in an opposing relationship to the first reflector. A tunable optical cavity is between the first and second reflectors. An active region is positioned in the cavity between the first and second reflectors. The photodetector is polarization independent. An MQW light absorber is included converts light to electrons. A dual usage HCG VCSEL-detector includes a high contrast grating (HCG) reflector first reflector, and a second reflector in an opposing relationship to the first reflector. A tunable optical cavity is between the first and second reflectors. An active region is positioned in the cavity between the first and second reflectors. The dual usage HCG VCSEL-detector that operates as a dual usage HCG VCSEL and as a tunable photodetector.

The invention relates to a dynamic wavelength identification method and a device with fast temperature tuning of a laser diode, the periodic current is imposed on a thermoelectric refrigerator in the laser diode component for realizing the fast scanning of the temperature of a laser; the real-time resistance value is obtained by sensing the voltage values at two ends of an NTC thermosensitive resistor in the laser diode component, the resistance value is converted to the real-time temperature value of the thermosensitive resistor, the temperature compensation value is figured out through the temperature change rate on the thermosensitive resistor, and then the pre-estimated temperature of a laser cavity is obtained; and a known tuning transfer function of the laser diode is utilized to obtain the real-time output wavelength of the laser according to the format lambda (t) is equal to F lambda (i(t), T(t)). The on-line identification with open-loop drive and advanced algorithm is adopted for simplifying the hardware structure of a system and reducing the cost of the system. The method and the device can greatly improve the temperature tuning rate, and give out the dynamic wavelength during the temperature fast tuning process in an on-line manner, and the test inspection proves that the identification precision of the wavelength can achieve the pm order and be not affected by the fluctuations of the environmental temperature.

The invention relates to a superposed sequential setting method of inhibition band parallel reactor compensation line three-phase reclosing overvoltage, belonging to the power system relay protection technology field. The method comprises the following steps: by utilizing a WARD equivalent method, calculating equivalent impedances of a head end bus and a tail end bus of a fault line, and determining a large power supply side and a small power supply side; according to a terminal voltage size of a fault phase after trip-out, discriminating a fault property; when the fault is a transient fault, if line actual compensativity is less than critical compensativity, superposing the large power supply side, conversely, superposing the small power supply side; if the fault is a permanent fault, calculating an arithmetic product of a power frequency voltage step-up ratio when superposing the large power supply sides first and a healthy phase voltage step-up ratio caused by a single-phase ground fault, calculating an arithmetic product of a power frequency voltage step-up ratio when superposing the small power supply sides first and a healthy phase voltage step-up ratio caused by a single-phase ground fault, comparing the two arithmetic products, and superposing a side with a smeller arithmetic product. According to the method, line critical compensativity is only related to line length and a phase shift coefficient, raising superposed sequential setting speed in the transient fault is facilitated, amount of calculation is small, the method is simple and feasible, and a line single-phase fault can be reduced effectively to carry out overvoltage level of three-phase reclosing.

The invention relates to a Smith pre-estimation control method based on an improved neural network. The method comprises the following steps of acquiring input and output data of a large-lag controlled object as a preliminary sample and performing time lag elimination; determining number of input layer nodes and output layer nodes of a BP neural network, and furthermore determining the number of hidden layers and the number of hidden layer nodes; determining the length of a genetic algorithm individual; obtaining an optimal individual by means of the genetic algorithm, decoding the optimal individual for obtaining an optimal initial weight and threshold of the BP neural network; training the BP network, and identifying a controlled object and a non-lag part of the controlled object by means of the BP network; and transmitting input and output information after BP neural network identification to a PIC controller which is set by the RBF neural network, and realizing pre-estimation control by means of the PID controller after setting. The Smith pre-estimation control method can realize better controlling on the large-lag controlled object.

In a method for calibrating or aligning a multistage selective amplifier including an oscillator circuit and at least one tuning circuit, the tuning voltages respectively necessary for aligning the respective tuning circuits to the required receiving frequency are calculated directly from a mathematical relationship between the respective tuning voltage and the oscillator voltage. In order to achieve this, a characteristic multiplicative coefficient and a characteristic additive factor for each tuning circuit are stored in a memory upon manufacturing or switching on the device. In order to select a desired receiving frequency, the respective stored values as well as an oscillator voltage are provided to an amplification circuit, which correspondingly amplifies the oscillator voltage by the multiplicative coefficient and the additive factor and then provides the resulting output value as a tuning voltage to the respective tuning circuit. Thus, all necessary tuning voltages can be determined from the two respective stored values per tuning circuit, as necessary for selecting any desired receiving frequency.

The invention discloses a tunable laser based on a graphene FP cavity, which belongs to the technical field of optoelectronic devices and aims at solving the problems that the laser in the prior art is narrow in output wavelength range, the tuning speed is slow, the device structure is not compact and is hard to integrate. The tunable laser based on the graphene FP cavity comprises a substrate (1), a buffer layer (2), a lower optical packet layer (3), a lower barrier layer (4), an active layer (5), an upper barrier layer (8), an upper optical packet layer (9) and an ohmic contact layer (10) sequentially arranged from bottom to top, wherein a first grating (6) and a second grating (7) located at two sides of the active layer (5) are also arranged on the lower barrier layer (4); and the first grating (6) and the second grating (7) are tunable waveguide gratings adopting silicon waveguide-graphene.

The invention relates to a precision optical frequency tunable laser. The laser includes: a laser gain medium, an intracavity collimating lens, an active optical phase modulator, a tunable acousto-optic filter and an intracavity total reflection mirror all arranged sequentially in a laser cavity, and the tunable laser further includes an active polarization rotator, a polarization beam splitter, two etalons, a temperature control system attached to the etalons, two total reflection mirrors, a radio frequency signal source, a laser pumping source, an active optical phase modulator drive source, an active polarization rotator drive source and a laser drive control circuit. Through the temperature control system attached to the etalons, stable laser output and the precision optical frequency tuning less than 1 GHz within a wide spectrum range can be realized, thereby greatly reducing the bandwidth requirements in achieving narrowband filtering for the tunable acousto-optic filter. The invention is compact with high performance, low cost for volume production and installation, and achieves stable tunable laser output within a wide spectrum range.

The invention discloses an electrooptical adjustable filter based on a sub-wavelength high-contrast grating and relates to the technical field of photoelectrons. The electrooptical adjustable filter comprises a substrate, an interdigital sub-wavelength grating, a transparent conduction layer and electrodes that are stacked sequentially from the bottom up, wherein an electrooptic material layer flush with the transparent conduction layer is arranged at an exposed part on the surface of the substrate; the two electrodes are connected with an external circuit to form an electric field between grating ridges; and a refractive index of a material of the interdigital sub-wavelength grating is much greater than those of materials of the substrate, the photoelectric material layer and the transparent conduction layer. The filter is reasonable in structural design, and can obtain high quality factor resonance and an adjustable filtration spectral range via reasonable selection of grating parameters, and tune filtration wavelength via voltage modulation; further, the refractive index of an electrooptic material is regulated based on an electric field effect; and compared with a mechanical adjustable filter, the tuning precision and tuning speed are greatly improved and increased. The filter is simple in structure, the materials are easy to obtain, and large-scale production and application are facilitated.

The invention discloses a coherent laser radar system based on optical phase locking. The system carries out the large-bandwidth modulation of narrow-linewidth laser through a phase modulator, the photoelectric conversion of modulated signal light and local oscillation light is completed through an IQ mixer and a balance detector, and then the phase discrimination is realized through a multiplier and a low-pass filter. An obtained error signal is fed back to the optical modulator to correct the frequency and phase of the signal light, optical phase locking of the signal light to the local oscillation light is completed, and the signal light after phase locking is subjected to power amplification through the optical amplifier for target detection. The system solves the random phase caused by the modulation process and optical transmission of the coherent laser radar, and can be used for coherent accumulation and imaging of the coherent laser radar.

The invention provides a looped network-based data transmission method with a main mode for a localized protection device. According to the invention, the transmission of management data is realized through the gigabit ring network; the setting speed of a pressing plate and a fixed value is improved; meanwhile, the ring network is used for monitoring the operation state of the protection sub-machine, the mode of the management host and the protection sub-machine is adopted, internal management data intercommunication of the protection device is achieved, the dependence of the protection deviceon a management unit is reduced, the protection reliability is improved, and meanwhile the reliability of management data transmission is further enhanced through the data transmission fault-toleranttechnology.

The invention discloses a liquid medium-based adjustable spiral cavity filter, which comprises a metal cover plate, a metal cavity, an SMA joint, a Teflon tube, a spiral structure harmonic oscillator and a coupling window, and is characterized in that a high dielectric constant medium liquid column is loaded in the spiral cavity filter, and the equivalent electrical length of the spiral structure is changed by changing the height of the liquid medium column, so that the spiral structure can be adjusted; the working frequency of the cavity filter is adjustable. The frequency of the cavity filter is adjustable by using the liquid medium, the cavity filter has the characteristics of high tuning speed, high precision, simplicity in control and low cost, and the size of the cavity filter is greatly reduced under the same frequency by adopting the resonant cavity with the spiral structure.