494results about How to "Adjustable frequency" patented technology

A tunable earphone includes a body, a front cavity, a rear cavity and a decorating plat. The body includes a small air hole and a large air hole. The front cavity and the rear cavity are respectively disposed on the body. The decorating plate covers the rear cavity and includes a receiving groove, a shielding member and a channel. The shielding member and the channel are disposed in the receiving groove. When the decorating plate is rotated to a first position, the shielding member shields the large air hole, the channel corresponds to the small air hole, so that the front cavity communicates with the rear cavity through the channel. When the decorating plate is rotated to a second position, the shielding member shields the small air hole, the channel corresponds to the large air hole, so that the front cavity communicates with the rear cavity through the channel.

An earth station receives a return signal via more than one satellite link from a mobile terminal using TDMA. The earth station selects one or more of the satellite links for transmitting a forward signal on the basis of the quality of signal received via each link. The earth section allocates frequency channels to the mobile terminals according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals which share the same frequency channel is approximately the same. The satellite includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.

The invention relates to a sensing method with an optical-fiber Bragg grating laser device. An optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double wavelength/multiple wavelength optical-fiber Bragg grating laser device is formed under the action of a pump light source and used as a sensor. When the outside strain, temperature and other physical quantities act on the sensing system, the beat signal frequency among the double wavelength or multiple wavelength laser can shift, and counter stress, temperature and other physical parameters can be measured precisely by detecting the beat signal frequency information. The invention has the advantages of simple manufacture, stable and reliable operation, stable measurement result and high precision, and is free from the interference of light intensity, polarization and other optical information quantities. The multipoint distribution sensing measurement can be realized in a frequency-division multiplexing mode. An electrooptical modulator is added before the spectrum analyzer starts detection so as to randomly adjust the beat signal frequency, thereby greatly reducing the spectral range of the spectrum analyzer and reducing the detection cost.

An antenna device for a portable radio communication device adapted for receiving radio signals comprises an internal radiating element (10) comprising at least one feeding portion (21, 22) connected to a receiver circuit (40). The radiating element (10) comprises an electrical impedance (30) that is controllable in dependence on the desired frequency range of the received signals, wherein the feeding portion (21, 22) is connected to a feeding input (40a, 40b) on the receiver circuit and the control input of the controllable electrical impedance (30) is connected to an output (40c) on the receiver circuit (40) intended for the control of the VCO resonance frequency of the receiver circuit. In that way an antenna device can be provided inside the casing of a small sized portable radio communication device, which has good performance throughout a narrow sub-band of a frequency band having a relatively low frequency, wherein the narrow sub-band can be adjusted in frequency so as to cover the entire frequency band, such as the FM radio band.

A voltage-controlled oscillator including an active oscillator circuit, an inductor, and capacitive circuits is disclosed. The capacitive circuits are selectively turned on and off to control the frequency of the voltage-controlled oscillator. Particularly, the inductor and the capacitors in the capacitive circuits form LC circuits that provide feedback to the active oscillator circuit. To avoid damage to the switches in the capacitive circuits, the capacitive circuits further comprise resistors. The resistors can be configured in several different ways so that the voltage-controlled oscillator can have a high degree of reliability, and a wide tuning range with constant phase noise performance.

There is provided an improved TIG welder comprising a power source for performing an AC TIG welding process across an electrode and a workpiece with a controller for creating an AC waveform. The controller having a synergic input device with an input for receiving a signal level representing a desired set current for the welding process and an output signal determining an aspect of the waveform and representing a non-linear relationship between peak positive current and peak negative current for certain desired set welding currents.

In a digital hearing aid device (1) frequency modification is employed above a lower spectral bound and in accordance with a compression factor. The frequency modification is dynamically adjusted in dependence on a sound environment analysis (10) or an end-user input (30), by modifying the frequency modification parameters such as a lower spectral bound and a compression factor. The adjustment can be based on an interpolation between predefined parameters. In certain sound environments, such as loud noise, own-voice and telephone conversations, frequency modification is reduced or switched off. The proposed solutions have the advantage that the occurrence of disturbing noise and of distortions of harmonic relationships at the end-user's ear is reduced and signal processing resources as well as battery resources are saved.

The invention discloses a detecting method of a weak periodic signal based on a chaotic system and wavelet threshold denoising, which comprises the following steps of: firstly carrying out wavelet decomposition on collected information, and determining a decomposition scale according to an actual signal-to-noise condition; denoising a wavelet high-frequency coefficient after the wavelet decomposition, wherein in the process of wavelet threshold denoising, the selection of a threshold is an important problem and directly influences a denoising result, so that the invention firstly provides a method for determining the threshold according to the scale for carrying out coefficient threshold processing to improve the denoising effect; reconstructing a signal after denoising, merging the signal to be detected after wavelet denoising reconstruction as one part of the driving force of the chaotic system into a chaotic detecting system, further inhabiting noise interference by utilizing the characteristics of the chaotic system for strong noise immunity, periodic weak signal sensitivity and the like, and effectively extracting the weak signal. The invention improves the detection threshold and the signal-to-noise ratio purely based on the chaotic detecting system.

The invention belongs to the field of microwave photonics, and discloses a system and method for frequency tunable microwave phase shifting. The method comprises the following steps that after a continuous light carrier is splitted, one beam of the continuous light carrier is processed by a MZ Mach-zehnder, and double-sideband optical signals restrained by the carrier are produced; the other beam of the continuous light carrier is processed by a phase modulator, and phase-shifted light carrier signals are produced; two beams of light signals are combined in a wave mode, one one-step sideband is removed through a tunable micro-ring filter in a filtering mode, a frequency-moved carrier signal and a phase-shifted carrier signal are obtained, photovoltaic conversion is carried out through a photoelectric detector, and a phase shift microwave electrical signal is produced; the resonant frequency of the tunable micro-ring filter is equal to any one-step sideband of the two one-step sidebands output by the MZ Mach-zehnder by changing the frequency of an input voltage drive signal and the resonant wavelength of the tunable micro-ring filter, and the frequency of the phase shift microwave signal is changed. The system and method for the frequency tunable microwave phase shifting is stable in output performance, fast in phase shift adjusting response, small in output microwave range fluctuation and continuously adjustable in wide frequency range.

A system and method for regulating real-time the heartbeat frequency of the host according to the user-requested frequency, wherein the heartbeat frequency of the host is regulated through the service request signal sent from the user's end to the host by making use of a cluster system comprising a host and a backup host. Firstly, a frequency correspondence table is established. The host and the backup host transmit signals to each other at a predetermined frequency, which is set to the most recent heartbeat frequency of the host. Then the transmitting times of a plurality of service request signals are recorded to calculate the frequency of the most recent service request signal. Finally, the most recent heartbeat frequency of the host and the frequency of the most recent service request signal are compared to determine if the heartbeat frequency of the host needs to be regulated.

The invention relates to a damping device, especially active vibration absorber and the control method. Said vibration absorber in vibration absorbing system comprises main drive part, vibration absorbing block, changeably stiffness part, magnetic insulation block and U-shaped bracket. The main drive part comprises permanent magnet and column electromagnet. The column iron core is fixed on the bottom of bracket and permanent magnet is fixed with vibration absorbing block by magnetic insulation block. The changeably stiffness part comprises U-shaped electromagnet and MR elastomer. U-shaped iron core is opened downward, of which MR elastomer are set on two inner sides respectively. Vibration absorbing block is set among two chips and the lower end of U-shaped iron core is fixed with the upper end of U-shaped bracket to form inner space where the main drive part, vibration absorbing block, MR elastomer and magnetic insulation block are accommodated. The control method is that the changeably stiffness part and main drive part are controlled respectively according to frequency, amplitude value and phase information of vibration-damping objects. The invention belongs to half-active and active combined control and is provided with low consuming and wide vibration-damping frequency so on.

The invention discloses a plant tissue culture environmental information monitoring and simulating system. The plant tissue culture environmental information monitoring and simulating system comprises a tissue culture box, a monitoring unit and a simulating unit, wherein the monitoring unit is formed by a collection module, a wireless transmission module and a display processing module. The collection module collects tissue culture environmental information of plants in the tissue culture box, and sends the environmental information to the transmission module. The wireless transmission module uploads the received environmental information to the display processing module. The display processing module stores, processes, displays and indexes the environmental information. The simulating unit carries out manual simulation on the tissue culture environmental information of the plants in the tissue culture box. The plant tissue culture environmental information monitoring and simulating system is convenient to operate, complete in functions, strong in pertinence, capable of achieving intelligent control for the information such as illumination, temperature, carbon dioxide (CO2) and the like in a greenhouse environment, and is suitable for greenhouse plant tissue culture and for various places such as plant tissue culture boxes, illumination culture boxes, phytotrons, facility agriculture, and has expansibility.

A headphone structure for adjusting audio frequencies is provided, which comprises a front housing, a rear housing, a sound-producing unit in the front housing and an elastic ear-contacting body sleeving the front housing. The front housing has at least one slot or recess, and the elastic ear-contacting body sleeves the front housing to form at least one gap. The headphone structure for adjusting audio frequencies of the present invention has better results for the adjustment of bass frequencies. In addition, the headphone structure of the present invention is not complicated and is easy to manufacture. The headphone structure of the present invention can be applied to various types of headphone, such as in-ear headphones and circumaural headphones.

A dual-band antenna includes a planar conductive layer comprising a conductive region and a central non-conductive region. The conductive region and the non-conductive region together define a pair of interconnected F-slot structures, and a loop strip structure coupled to and disposed around the F-slot patch slot antenna structures.

The invention discloses a preset cavity type SOI (silicon on insulator) substrate film bulk acoustic wave filter and a manufacturing method thereof, relating to the field of electronic devices. The filter is formed by electrically cascading a plurality of film bulk acoustic wave resonators which are manufactured on a preset cavity type SOI substrate, wherein each resonator comprises a piezoelectric film, a base electrode and a top electrode; a groove is arranged on the upper surface of substrate silicon of the SOI substrate; a sealed cavity is formed by the substrate silicon having the groove and top silicon; the top silicon is transferred from a groove-free SOI substrate by using a bonding technique and has even and controllable thickness; the cascaded mode of the filter includes a balancing bridge type, a stair type and a grid type; the frequency of the filter is adjustable and can be adjusted by controlling the thickness by controlling the etching time of the top silicon above the cavity; the electrodes of the resonators are approximate to oval, which is beneficial to the enhancement of the energy trap action; and a duplexer and a multiplexer can be formed by using the filter. In the invention, the advantages of SOI material are taken, the relative technique of a sacrifice layer is unnecessary, the process is simple, and the filter and the manufacturing method thereof are suitable for batch production.

The invention discloses a microwave photonic band stop filter based on a Microring-Mach Zehnder interference (MR-MZI) structure, which comprises a semiconductor laser, a polarization controller, a phase modulator, an optical band pass filter, an MR-MZI integrated optical filter unit and a photoelectric detector. Narrow bandwidth filter is realized through adjusting the coupling interval between microring resonators in the MR-MZI integrated optical filter unit; through adjusting the bias voltage of each heating electrode in the MR-MZI integrated optical filter unit, the amplitude and the phase of signals are regulated; the amplitude response and the phase response of the microring are used for being combined with the MZI structure in the MR-MZI integrated optical filter unit to generate fully destructive interference, and an ultra high inhibition ratio is realized. According to the microwave photonic band stop filter provided by the invention, on the basis of the narrow bandwidth, the ultra high inhibition ratio is realized, and the microwave photonic band stop filter performance is improved.

The present invention provides a communication semiconductor integrated circuit wherein a first control voltage for a voltage-controlled oscillator circuit is controlled based on a feedback signal sent from a PLL loop to generate a carrier frequency signal used as a carrier, and under the generation of the carrier frequency signal, a second control voltage for the voltage-controlled oscillator circuit is controlled based on the output of a DA converter circuit for DA-converting a code generated based on transmit data to thereby frequency-modulate an oscillation signal. The communication semiconductor integrated circuit is provided with a frequency adjustment/control circuit which measures the frequency of an oscillation output of the voltage-controlled oscillator circuit and adjusts a reference current value of the DA converter circuit according to the difference between the measured value and a target value to thereby correct the frequency.

The invention discloses a reliability test device and a reliability test method for a numerical control machine hydraulic system, and aims to solve the problem that the numerical control machine hydraulic system is free of reliability test device and reliability test method. The reliability test device for the numerical control machine hydraulic system comprises a mounting part of a tested hydraulic system, an analog loading part and an automatic control part, wherein a first hydraulic cylinder branch circuit of a confluence plate of the mounting part of the tested hydraulic system is connected with a hydraulic cylinder rodless cavity oil pipe of the analog loading part, and a second hydraulic cylinder branch circuit of the confluence plate is connected with a hydraulic cylinder rod cavity oil pipe; a lower programmable logic controller (PLC) of the automatic control part is connected with a first three-position four-way electromagnetic reversing valve, a second three-position four-way electromagnetic reversing valve, a third three-position four-way electromagnetic reversing valve and a fourth three-position four-way electromagnetic reversing valve of the mounting part of the tested hydraulic system through electric wires; an A/D acquisition card of the automatic control part is connected with a pressure sensor and a pull pressure sensor through electric wires. The invention further provides a reliability test method for the tested hydraulic system.

The invention relates to a controllable high performance wireless power supply device applied to biological implantation materials, which comprises an SCM control module, a voltage conversion and amplifier module, a coil coupling transmission module and a vivo commutating and voltage-stabilizing module. The SCM control module generates PWM wave to control the output frequency and efficiency of the voltage conversion and amplifier module; the voltage conversion and amplifier module is constructed by a Class-E power amplification circuit which receives, converses and amplifies 3 to 5V direct current signals into alternating current to be output to the coil coupling transmission module; the coil coupling transmission module realizes transmission from the vitro to the vivo; the vivo commutating and voltage-stabilizing module commutates and filters alternating current and stabilizes into stable 3.3V direct current to supply power to medical instruments in the implantation materials. The device provided by the invention has small volume, adjustable frequency and high transfer efficiency of wireless alternating current, is easy to operate and realizes wireless transmission with respect to the power supply to medical implanted devices.

The invention discloses a habitable room flower multifunctional nursing system which comprises a flower cultivation box which provides a growing environment for flowers, a collecting processing unit, an LED light complement unit, a humidification unit, a sterilization unit and a power supply unit. The collecting processing unit collects humidness and illumination information of the flower growing environment in the flower cultivation box and sends control instructions to the LED light complement unit and the humidification unit respectively according to the information, the LED light complement unit is used for achieving three-dimensional lighting of the flowers, the humidification unit is used for achieving intelligent humidification of the flowers, the sterilization unit is used for disease control of the flowers, and the power supply unit provides direct-current voltages for the other units. The habitable room flower multifunctional nursing system integrates habitable room flower light complementation, humidification and sterilization, pertinency is strong, the system can be used in a combined mode or used in a single-function mode, good expansibility is achieved, and application market on pot culture fruit trees, facility horticulture and the like is wide.

The invention relates to a laser detection and control system for barriers between a shield door of a metro platform and a train door, comprising a monitoring unit, a control unit and an alarm unit, wherein, the controller comprises a CPU module, a liquid crystal terminal, a signal isolator, buttons and a safety relay; generating lasers are respectively installed on a front bracket, and a laser receiver or a laser reflection plate is installed on a rear bracket corresponding to the front bracket; the control ends of the generating lasers are connected with the output end of the controller, and the output end of the laser receiver is connected with the input end of the controller; the corresponding output end of the controller is correspondingly connected with the control input end of the shield door; and the corresponding output end of the controller is connected with a buzzer and a caution light of the platform. The laser detection and control system realizes the intelligent operation of judging the existence of barriers between the shield door of the metro platform and the train door, has the advantages of compact integral structure, reasonable cost, easy and convenient installation, simple and intelligent operation, stable and reliable performance, higher practicability and favorable development prospect, and is applicable to metro platform.

A magnetostrictive transducer that generates a large shear horizontal (SH) wave useful for non-destructive testing of a plate member, and method and apparatus for structural health monitoring by using the magnetostrictive transducer. The magnetostrictive transducer includes: a magnetostrictive patch array comprising a plurality of magnetostrictive patches that have different radii of curvature, and have the same center of curvature when arranged on a plate member and form an overall fan-shape; a static magnetic field forming unit comprising two magnets that are respectively installed on both sides of the magnetostrictive patch so that a magnetic field is formed in parallel to an arc direction of the magnetostrictive patch; and a dynamic magnetic field forming unit comprising a wound coil comprising a plurality of curved portions.